Dissertations / Theses on the topic 'Oil well drilling'
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Wang, Hong. "Near wellbore stress analysis for wellbore strengthening." Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1338926861&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
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Ozkan, Erdal. "Performance of horizontal wells /." Access abstract and link to full text, 1988. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/8825498.
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CHIEZA, CAROLINA PONTES. "DIAGNOSTICS OF OPERATIONAL PROBLEMS DURING OIL WELL DRILLING." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2011. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=19161@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORA perfuração de poços de petróleo é uma operação complexa e de elevado risco e custo financeiro. Com o passar dos anos o número de poços horizontais e de longo alcance perfurados aumentou consideravelmente devido à existência de reservatórios mais profundos e de difícil acesso, além da necessidade de se obter uma melhor eficiência na extração do petróleo. Juntamente com este aumento na complexidade da perfuração surgiram problemas operacionais que, por muitas vezes, não são identificados e acabam sendo responsáveis pela maior parte do tempo não produtivo da operação elevando, assim, seus custos diários. Logo, o estudo destes problemas é de extrema importância para se garantir condições seguras de operação, além de contribuir para a otimização da mesma, mitigação dos efeitos causados e uma maior rapidez e eficácia nas tomadas de decisões. O presente trabalho apresenta uma metodologia de identificação de problemas operacionais a fim de otimizar a perfuração de poços, através da utilização de recursos computacionais, para gerar análises de previsão de torque, arraste e hidráulica e, posterior, comparação com os dados de perfuração obtidos, em tempo real, dos sensores de mudlogging e da ferramenta de PWD. A caracterização dos problemas foi realizada com base nos dados reais de poços horizontais, perfurados na Bacia de Campos, mediante a identificação de possíveis desvios importantes, que não estavam previstos, nos parâmetros de perfuração. Através da retro-análise dos dados de perfuração dos poços foi possível diagnosticar alguns problemas operacionais ocorridos durante esta operação, tais como: perda de circulação, prisão da coluna de perfuração, washout no tubo de perfuração e dificuldade de avanço causada por uma limpeza deficiente, pelo enceramento da broca e pela vibração na coluna de perfuração. Além disso, foram destacados também alguns exemplos que mostraram variações na tendência do torque em função de mudança na litologia do poço.
Drilling is a complex and a high risk process which involves high financial cost. Over the years the number of horizontal wells and extended reach wells increased, due to the existence of deeper reservoirs, which are more difficult to access, in addition to the need of having an improvement in the oil production efficiency. Along with this increased complexity of drilling, unidentified operational problems end up being responsible for most of the non-productive time and daily cost increase. Thus, analyzing such problems it is very important to ensure safe operating conditions, optimize drilling operation, control causes/effects and have a faster and efficient decision-making capability. This paper presents a methodology to identify operational problems in order to optimize drilling operation using computer resources to predict torque, drag and hydraulic effects and later on to compare with the drilling data obtained in real time from mudlogging sensors and PWD (Pressure While Drilling). Cases were based on real time data from horizontal wells drilled in Campos Basis, Rio de Janeiro, and the problems were identified with unforeseen changes in drilling parameters trend. After studying the available well data, it was possible to diagnose several operational problems occurred during drilling, such as: lost circulation, stuck pipe, drill pipe washout and difficulty in drilling due to a poor hole cleaning, bit balling and drill string stick-slip vibration. In addition, it was also highlighted some examples that showed variations in the torque trend due to lithology changes.
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PICARD, NICOLAS. "DEVELOPMENT OF NOVEL HYDRAULICS FOR OIL WELL DRILLING." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1025637714.
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Becker, Thomas Edward. "Correlations for drill-cuttings transport in directional-well drilling /." Access abstract and link to full text, 1987. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/8712608.
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Mishra, Nekkhil. "Investigation of hole cleaning parameters using computational fluid dynamics in horizontal and deviated wells." Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5111.
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Thesis (M.S.)--West Virginia University, 2007.Title from document title page. Document formatted into pages; contains x, 65 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 58-60).
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Kartoatmodjo, Rudjuk Sinung Trijana. "A model for finite conductivity horizontal wellbores /." Access abstract and link to full text, 1994. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/9522755.
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Hernæs, Marthe Pernille Voltersvik. "Human related root causes behind oil well drilling accidents." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for petroleumsteknologi og anvendt geofysikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-20384.
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Many accident investigation techniques and other methods used by the petroleum industry today list a set of underlying human related causes and subsequent improvement suggestions. Do these techniques address the root cause behind the problem so that the appropriate initiatives can be implemented? The focus of the present thesis was to determine the human related root cause of two major accidents in the North Sea. This in order to give recommendations to improve the safety levels in the organisation. In order to achieve the above-mentioned goals, the IPT Knowledge Model was adapted to the given accidents. The data input into the model was based on interpreted observations from former investigation reports. The analysis of the blowout on Snorre A and the well control incident on Gullfaks C resulted in 49 and 63 observations respectively. For both accidents, the Human Factor that was indicated to have the largest affect on the accidents was Training and Competency (29% for Snorre A and 19% for Gullfaks C). Lack of competence was indicated as the majority subclass. Collectively, management and supervision, or lack thereof, was also indicated as being a contributing factor to the accidents. These final results coincide with the findings in other investigation reports. However, these are more acute, indicating a specific area of improvement within the company. By increasing the competency levels within the company and ensuring that the leaders and management have the proper tools to follow-up their employees and their operations, the safety levels and culture will improve.
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Campos, Wellington. "Mechanistic modeling of cuttings transport in directional wells /." Access abstract and link to full text, 1995. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/9527819.
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Huang, Xiaoguang. "Limit state design of oil and gas well casings." Thesis, University of Wolverhampton, 2002. http://hdl.handle.net/2436/99757.
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Essiwi, Mohamed Milad Ahmed. "Validation of CFD modeling for oil well drilling fluid flows." Thesis, University of Newcastle Upon Tyne, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430771.
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Chidamoio, João Fernando. "Experimental and numerical modelling of gaslift cavitation and instabilities in oil producing wells." Thesis, University of Aberdeen, 2018. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=239215.
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AL-Rashidi, Abdulrahman F. "Designing neural networks for the prediction of the drilling parameters for Kuwait oil and gas fields." Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=1209.
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Thesis (M.S.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains x, 76 p. : ill. (some col.), map (some col.). Includes abstract. Includes bibliographical references (p. 54-55).
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Ali, Md Wazed. "A parametric study of cutting transport in vertical and horizontal well using computational fluid dynamics (CFD)." Morgantown, W. Va. : [West Virginia University Libraries], 2002. http://etd.wvu.edu/templates/showETD.cfm?recnum=2281.
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Thesis (M.S.)--West Virginia University, 2002.Title from document title page. Document formatted into pages; contains x, 108 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 42-46).
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Acheampong, Theophilus. "Essays on North Sea oil and gas economics : offshore safety economics and third party access to infrastructure in the upstream oil and gas industry." Thesis, University of Aberdeen, 2017. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=232397.
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This thesis explores two themes on upstream oil and gas economics centred on offshore safety economics and third party access to infrastructure in the United Kingdom Continental Shelf (UKCS). The first part involves work that explores the nexus between the offshore safety regime and safety outcomes. It contributes to the literature by explaining the post-Piper Alpha safety regime changes with regard to our understanding, framing of safety decision making and benchmarking of safety outcomes. The second part investigates third party access to infrastructure issues in the UKCS. It contributes to our understanding of how different third party access to infrastructure arrangements can be utilised to maximise economic recovery. Each chapter addresses fundamental issues of North Sea oil and gas operations through the application of microeconomic, operations research and econometric methods within a formal analytical framework. The results provide insights into decision-making complexities in the upstream oil and gas industry by guiding policy makers. Specifically, part one of this thesis looks at safety performance in the post-Piper Alpha era in the UKCS. It investigates ways through which a more comprehensive and theoretically informed framework can be used to understand the linkages that arise when dealing with safety regulations and their impacts on the offshore oil and gas industry. Our objective is to empirically ascertain the determinants of offshore hydrocarbon releases within the context of the post-Piper Alpha offshore safety regime regulations. This is done using an observed number of hydrocarbon releases linked to a population denominator data of the number of the installations present in the UKCS. Three research problems are examined: (1) the transmission mechanisms through which safety regulation influence firm and industry productivity; (2) the assessment methods utilised in measuring and benchmarking regulatory outcomes in terms of safety compliance; and (3) the extent to which safety policies contribute to enhancing safety levels in the oil and gas industry. We initially review the background and literature on offshore safety with a particular emphasis on the UKCS in Chapter 2. We also frame our research questions and underlying hypothesis here. In Chapter 3, we present our underlying empirical framework and model specifications followed by some descriptive analysis of the hydrocarbon releases data. The results of the various econometric model specifications are analysed in Chapter 4. The second part of the thesis explores how possible different ownership patterns (including access arrangements) might affect the economic viability of exploiting remaining resources in the UKCS. This section attempts to answer two critical questions namely how the impact of the separation of infrastructure and field ownership affect economic recovery and the impact of taxation on field and hub economics in a mature oil basin. We explore how possible different ownership structures and access arrangements might affect the economic viability of remaining UKCS reserves. We apply a mixed integer programming (MIP) model to field data from the Northern North Sea. Specifically, we examine how the unbundling of infrastructure and field ownership, as well as different cost sharing and tariff arrangements, affect the long-term economics of hubs and their user fields. Regarding the layout, Chapter 5 talks about access to infrastructure issues in the UKCS namely the regulatory framework for access and related legislation. It leads to the development of a conceptual framework and model based upon which extractions are made to capture the various potential market outcomes. In Chapter 6, the empirical model, which utilises the mixed integer programming approach, is discussed. The data sources and characterization, as well as the presentation of the results from the Baseline Model, are presented in Chapter 7. The analysis of the Tax Model and the Cost Sharing plus Tax Model including structure and simulated results with underlying assumptions are presented in Chapter 8. Finally, Chapter 9 leads to a thorough discussion of the results followed by conclusions and policy recommendations.
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Farrelly, M. "Performance evaluation and selection of rotary drilling bits." Thesis, University of Newcastle Upon Tyne, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234404.
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Shewring, Nigel Ivor Edward. "Interactions at the clay/polymer/water interface." Thesis, Sheffield Hallam University, 1998. http://shura.shu.ac.uk/20358/.
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The thesis investigates the behaviour of aqueous montmorillonite suspensions and also the interactions between montmorillonite as a free standing film and in highly dispersed aqueous suspension with water soluble polymers used as additives in water based drilling fluids. FTIR microscopy and FTIR ATR spectroscopy have been employed to study in-situ dehydration of fully dispersed aqueous montmorillonite suspensions. The IR spectrum of the dispersed bentonite shows significant differences from that of a dry bentonite powder, which have been attributed to the hydration of the exchangeable cation. Drying, or concentrated salt solution causes the differences to disappear and this is attributed to the exchangeable cation settling back to its ditrigonal cavity in the silicate sheet of the mineral under these conditions. The adsorption of various molecular weights of neutral polyacrylamide (PAM) onto montmorillonite has been studied using FTIR transmission, ATR spectroscopy and XRD. Shifts seen in the NH[2] stretching and bending bands have been interpreted as being due to H-bonding with the outer co-ordination sphere of exchangeable cations. KCl has shown to have some influence on this system. Another neutral polymer used extensively in water based drilling fluids is polyalkylglycol (PAG). The adsorption of two molecular weights of this polymer from aqueous solutions of various concentrations have been monitored both in the presence and absence of KCl. The physical form of the montmorillonite (either as a free standing film or as a dispersed suspension), the concentration of the polymer solution, the polymer molecular weight and the presence of KCl all have significant effects on the adsorption of polymer. The stabilisation of montmorillonite films by PAG and PAG/KCl solutions has been monitored by ATR spectroscopy, and the dehydration of these films by polymer has been monitored using FTIR spectroscopy and XRD. The interaction of PAG is thought to be via hydrogen bonding with the innermost co-ordination sphere of the exchangeable cations which thus presents a hydrophobic surface to solvent molecules, preventing the film from collapse. Since all water based drilling fluids are multi-component systems, techniques previously used have been employed to study the competitive adsorption of the polyalkylglycol and polyacrylamide components. Preferential adsorption of the PAG is seen in these systems either due to the mass transport effects (PAG is considerably smaller than PAM) or due to PAG removing all but the inner cation hydration sphere, and presenting a hydrophobic surface for the PAM, and therefore preventing its adsorption.
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Alkaragoolee, Mohammed Y. A. "Hybrid Modelling and Optimisation of Oil Well Drillstrings." Thesis, University of Bradford, 2018. http://hdl.handle.net/10454/16859.
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The failure of oil well drillstrings due to torsional and longitudinal stresses
caused by stick-slip phenomena during the drilling operation causes great
expense to industry. Due to the complicated and harsh drilling environment,
modelling of the drillstring becomes an essential requirement in studies.
Currently, this is achieved by modelling the drillstring as a torsional lumped
model (which ignores the length of the drillstring) for real-time measurement
and control. In this thesis, a distributed-lumped model including the effects of
drillstring length was developed to represent the drillstring, and was used to
simulate stick-slip vibration. The model was developed with increasing levels of
detail and the resultant models were validated against typical measured signals
from the published literature.
The stick-slip model describes the friction model that exists between the cutting
tool and the rock. Based on theoretical analysis and mathematical formulation
an efficient and adaptable model was created which was then used in the
application of a method of species conserving genetic algorithm (SCGA) to
optimise the drilling parameters.
In conclusion, it was shown that the distributed-lumped model showed improved
detail in predicting the transient response and demonstrated the importance of
including the drillstring length. Predicting the response of different parameters
along the drillstring is now possible and this showed the significant effect of
modelling the drillcollar. The model was shown to better represent real system
and was therefore far more suited to use with real time measurements.Iraqi Government, Ministry of Higher Education and Scientific Research.
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Alborzi, Mahmood. "Application of neural networks to real-time log interpretation in oil well drilling." Thesis, Brunel University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309502.
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Dangou, Mohamad Ali Abdulla. "Investigations of the filtration parameters of drilling fluids for optimising oil well productivity." Thesis, University of Aberdeen, 2007. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU239344.
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The main objective of this research was to gain further understanding of the behaviour of oil wellbore fluid filtrates, the various factors affecting filter cake quality, and how these can be controlled to reduce the invasion of the filtrate around the wellbore region. The investigations were intended to define filtration behaviour and filter cake parameters at different fluids with various particle size distributions and various wellbore conditions that are: different filtration pressures, different filtration times, and different shear rates acting on the cake surface during dynamic filtration conditions. The results indicated that all the above mentioned filtration parameters have a various degree of influence on the filter cake and filtration parameters. The forces acting on a particle suspended in the wellbore fluids during dynamic cake particle deposition were also analyzed and a dynamic filtration model was developed. This model can be used to determine the average critical shear rate of these particles and the frictional coefficient factors of the particles with the cake surface. The model has then been modified to predict equilibrium filtration flow rate at any shear stress (above the critical value) applied on the cake surface. Investigations on the transient stage of the dynamic filtration agreed with literature and showed that the size of particles deposited onto the cake decreased with increasing cake thickness, causing the particle size distribution of the dynamic filter cake to alter with cake thickness.
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Dudo, Anthony David. "An environmental controversy how newspapers framed coverage of the Bush administration's proposal to drill for oil and gas in the Arctic National Wildlife Refuge (Alaska) /." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 0.65Mb., 129 p, 2005. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:1428181.
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Leamon, Gregory Robert Petroleum Engineering Faculty of Engineering UNSW. "Petroleum well costs." Awarded by:University of New South Wales. School of Petroleum Engineering, 2006. http://handle.unsw.edu.au/1959.4/30599.
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This is the first academic study of well costs and drilling times for Australia???s petroleum producing basins, both onshore and offshore. I analyse a substantial database of well times and costs sourced from government databases, industry and over 400 recent well completion reports. Three well phases are studied - Pre-Spud, Drilling and Completion. Relationships between well cost factors are considered, including phase time, phase cost, daily cost, rig day rate, well depth, basin, rig type, water depth, well direction, well objective (e.g. exploration), and type of completion (P&A or producer). Times and costs are analysed using scatter plots, frequency distributions, correlation and regression analyses. Drilling times are analysed for the period 1980 to 2004. Well time and variability in well time tend to increase exponentially with well depth. Technical Limits are defined for both onshore and offshore drilling times to indicate best performance. Well costs are analysed for the period 1996 to 2004. Well costs were relatively stable for this period. Long term increases in daily costs were offset to some extent by reductions in drilling times. Onshore regions studied include the Cooper/Eromanga, Surat/Bowen, Otway and Perth Basins. Offshore regions studied include the Carnarvon Basin shallow and deepwater, the Timor Sea and Victorian Basins. Correlations between regional well cost and well depth are usually high. Well costs are estimated based on well location, well depth, daily costs and type of completion. In 2003, the cost of exploration wells in Australia ranged from A$100,000 for shallow coal seam gas wells in the Surat/Bowen Basins to over A$50 million for the deepwater well Gnarlyknots-1 in the Great Australian Bight. Future well costs are expected to be substantially higher for some regions. This study proposes methods to index historical daily costs to future rig day rates as a means for estimating future well costs. Regional well cost models are particularly useful for the economic evaluation of CO2 storage sites which will require substantial numbers of petroleum-type wells.
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Won, Suyoun. "Investigation of mud filtrate invasion using computational fluid dynamics." Morgantown, W. Va. : [West Virginia University Libraries], 2008. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=6038.
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Thesis (M.S.)--West Virginia University, 2008.Title from document title page. Document formatted into pages; contains xi, 59 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 52-54).
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Valås, Inge Åsmund. "A Data-intensive Approach to Prediction of Unwanted Events during Oil and Gas Well Drilling." Thesis, Norwegian University of Science and Technology, Department of Computer and Information Science, 2005. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9282.
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Prado, Mauricio Gargaglione. "A block implicit numerical solution technique for two-phase multidimensiaonal steady state flow /." Access abstract and link to full text, 1995. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/9523266.
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Al-Muraikhi, Ahmed J. "Evaluation of vertical multiphase flow correlations for Saudi Arabian field conditions." Dhahran, Saudi Arabia : King Fahd University of Petroleum and Minerals, 1989. http://library.kfupm.edu.sa/lib-downloads/1381127.pdf.
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McMahon, James S. "DYNAMO systems model of the roll-response of semisubmersibles." Master's thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-01262010-020130/.
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Khalili, Ali Petroleum engineering UNSW. "A review of critical coning rate correlations and identifying the most reliable equation." Awarded by:University of New South Wales. Petroleum engineering, 2005. http://handle.unsw.edu.au/1959.4/22388.
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The study of coning in oil production is important because of huge water production associated with oil production around the world each year. Estimation of critical coning rate has been the subject of numerous studies and a number of correlations have been reported. This study presents a review of the current available methods for estimating critical coning rate for both vertical and horizontal wells. The various methods and correlations are compared and the assumptions on which they are based evaluated. Following comparison made between the correlations, the most reliable theories are identified for both vertical and horizontal wells separately. Among the correlations for vertical wells, this study recommends two implicit methods presented by Wheatley and Azar Nejad et al. They determined the oil potential distribution influenced by water cone with a remarkable accuracy. For horizontal wells, two methods, Joshi???s equation and Rechem et al formula, are considered to be the most reliable. Joshi???s equation provides lower estimates than Chaperon???s correlation in which the water cone effect on oil potential was neglected. The Recham et al formula also gives a similar result. On the whole, the Rechem et al method is preferred.
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Martinovich, Tony. "Factors influencing the incidence rates of injuries and accidents among seafarers and rig workers providing support to the WA offshore oil and gas industry." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2013. https://ro.ecu.edu.au/theses/1084.
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The aim of this study was to identify, discuss and make recommendations regarding causal factors associated with injuries and accidents among seafarers and rig workers providing support to the WA offshore oil and gas industry. These incidents cause significant personal and economic burdens for employees, employers and the community in general.
A sample of 484 participants were recruited from a workforce of 9800 employees (approximately 5%). Participants were stratified into 2 cohorts; those who had suffered injury (286 – study group) and those who had not (198 - controls).
Data from the study group were stratified into oilrig workers and vessel seafarers. A one-way analysis of variance revealed that the injury incidence rate for the seafarers in the study group was significantly higher (mean 14.4 injuries) in the first quarter of each multi week work period ( "swing") (P=0.001), compared to means of 4.125 and 2.44 and 4 for the subsequent quarters. For the oil rig workers, the mean injury incidence rates across the four quarters remained similar.
It was recommended that a safety officer be assigned to each vessel to support workers for the 1st quarter of each swing. Implementation of this practice has been trialled in another study leading to a reduction in the number of incidents over a 12 month period (Brown, 2009). Other factors that influenced injury incidence rates were age and level of experience, with younger and less experienced workers being more injury prone. Encouraging older, experienced workers to mentor younger employees and to manage their workload according to their physical capabilities will be a useful intervention. The implementation of these recommendations will reduce the injury incidence rate of this unique cohort of employees thus reducing the economic burden of injuries and accidents to the employee, the employer and the community in general.
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Pelley, Dean. "Performance of twin falls davit & lifeboat evacuation system in extreme seas /." Internet access available to MUN users only, 2003. http://collections.mun.ca/u?/theses,169027.
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Lima, Neto Epaminondas Gonzaga 1989. "Comportamento PVT de misturas de dióxido de carbono em emulsões base n-parafina." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265928.
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Orientador: Paulo Roberto RibeiroDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: O cenário das perfurações de poços de petróleo vem mudando ao longo do tempo. Tanto pela necessidade do suprimento da demanda crescente por petróleo e gás quanto pela queda na produção de campos maduros, a perfuração de poços tem se deparado com ambientes mais agressivos a cada dia: maiores temperaturas, maiores pressões, maior afastamento em relação à costa e ambientes quimicamente mais hostis. A presença considerável de dióxido de carbono - CO2 - nos reservatórios aponta para uma maior preocupação na perfuração de poços em tais formações uma vez que, se esse componente adentra ao poço numa situação de kick, sua interação com a lama de perfuração pode alterar características importantes desse fluido, tais como: densidade, viscosidade e acidez. Este trabalho tem por objetivo investigar o comportamento PVT de sistemas contendo CO2 e líquidos com composição similar aos fluidos de perfuração à base de óleo: n-parafina pura e emulsão inversa. Foram realizados um estudo experimental de tais sistemas, uma simulação computacional, uma análise estatística dos dados obtidos para esse sistema com o intuito de avaliar as melhores correlações matemáticas para representação dos dados experimentais e aplicações de tais correlações em exemplos de controle de poço. Os resultados experimentais mostram que a simulação consegue reproduzir bem os dados experimentais (desvios de até 16%), apenas subestimando-os em frações molares de CO2 mais elevadas. Comparando os dados para o CO2, obtidos neste trabalho, com dados para o metano, obtidos da literatura, observa-se que o sistema contendo CO2 apresenta, dentre outras características, maior fator de formação de volume e solubilidade até 15 vezes maior que o sistema contendo metano. Por fim, ao examinar os exemplos de controle de poço, percebe-se que quanto maior é o teor de CO2 no sistema, maior é o valor do pit gain, tornando a presença de CO2 no sistema favorável à detecção do kick
Abstract: The scenario of oil and gas well drilling has been changing over the years. Not only because the need of supplying the increasing demand for petroleum and gas but also due to the decrease on the production of mature fields, well drilling has been constantly facing aggressive environments: higher temperatures, higher pressures, higher offshore distances and hazardous chemical environments. The presence of carbon dioxide - CO2 - on reservoirs leads to a concern on well drilling in these formations because the entrance of this gas into the well, in a kick situation, and its interaction with the drilling fluid can change important characteristics of this fluid such as: density, viscosity and acidity. This work aims to evaluate the PVT behavior of the systems containing CO2 and liquids similar to the ones used as base for oil-based drilling fluids: n-paraffin and inverse emulsion. An experimental study of these systems, a computational simulation, a statistical analysis of the data acquired aiming to evaluate the best mathematical correlations to represent these data and applications of these correlations were carried out. The experimental results show that the simulation can reproduce satisfactorily the experimental data (deviations up to 16%), only underestimating them at higher CO2 molar fractions. When comparing the data for CO2, obtained in this work, and the ones for methane, obtained from literature, it is possible to notice that the system containing CO2 has, among other characteristics, higher oil volume formation factor and solubility 15 times greater than the system containing methane. Finally, by examining well control examples, one can notice that the pit gain assumes higher values as the CO2 content increases making the presence of CO2 in the system favorable to kick detection
Mestrado
Explotação
Mestre em Ciências e Engenharia de Petróleo
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Chipindu, Njalo Socrates Chipongue. "Pos-analise em problemas de perfuração de poços maritimos de desenvolvimento." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263688.
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Orientadores: Celso Kazuyuki Morooka, Jose Ricardo Pelaquim Mendes, Kazuo MiuraDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica, Instituto de Geociências
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Resumo: Os problemas na perfuração de poços de petróleo são responsáveis pela maior parte dos tempos não produtivos, elevando assim os custos diários das operações. Portanto, o estudo e o entendimento destes problemas contribuirá para a otimização da perfuração, melhorando assim as práticas ou mitigando os efeitos severos das anormalidades. O presente trabalho apresenta três procedimentos para identificação das causas dos problemas que poderão auxiliar o jovem profissional a caracterizar os mais variados problemas que ocorrem durante a perfuração de um poço. Neste escopo são abordadas apenas as ocorrências pré-classificadas como dificuldade de manobra, dificuldade de avanço, e prisão. O estudo usa dados dos boletins diários de perfuração dos poços, dados de mudlogging, dados obtidos por ferramentas de monitoramento contínuo da perfuração e outros dados como o fluido utilizado, a configuração da composição de fundo, o desgaste de broca, o gráfico do caliper, litologia e trajetória do poço. A caracterização dos problemas é feita mediante a identificação e associação de eventos que levam a formular hipóteses das prováveis causas dos problemas. Dois grupos de pesquisa (Unicamp e Genesis do Brasil) em engenharia de poço implementaram separadamente os procedimentos propostos. Os resultados foram coincidentes para a maioria trechos de poços marítimos de desenvolvimento analisados, o que atesta a eficácia dos procedimentos diagnósticos. Este estudo é importante para indústria, pois pode maximizar a eficiência na perfuração, através da minimização e/ou eliminação dos tempos não produtivos, responsáveis por avultadas perdas econômicas, além de permitir tornar mais robustas as ferramentas de acompanhamento, em tempo real, das operações de perfuração, na tomada de decisões e na melhoria do processo de planejamento de poço
Abstract: Drilling problems are accountable for the majority of the non productive times in the industry raising the daily operations costs. Therefore, the study and understanding of the problems will contribute to the drilling optimization, improving the practices or by mitigating their severe effects. The present work presents three procedures for identification of causes of drilling problems which can help the young professionals to characterize a wide range of problems that occur while drilling an oil well. In this scope they are studied only the problems pre-classified by occurrence as: problems in tripping, problem in drilling ahead and stuck pipe. The study uses data from the daily drilling reports, mudlogging data, on time monitoring tools data and mud data, Bottom Hole Assembly composition, bit wear report, caliper data, litology and well trajectory. The characterization of the problems is made by identification and association of the events that lead to formulate the hypotheses of the probable causes of the problems. Two research groups (Unicamp and Genesis do Brasil) in well engineering implemented separately the three proposed procedures. The results were coincident for the majority of the analyzed intervals of offshore development wells, demonstrating the efficacy of the proposed procedures. This work is important to the industry since it leads to the drilling efficiency maximization by minimization and/or elimination non productive times that are the main responsible for economic losses, beside the fact that these findings can be used to boost the capacity of the monitoring and logging tools as well as to support the on time decision making and to improve well planning process
Mestrado
Explotação
Mestre em Ciências e Engenharia de Petróleo
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Atolini, Tarcila Mantovan. "Estudo de comportamento PVT de misturas de metano em emulsões base N-parafina a altas temperaturas, pressões e concentrações de metano." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265566.
Full textAbstract:
Orientador: Paulo Roberto RibeiroDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica, Instituto de Geociencias
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Resumo: Um dos avanços referentes ao desenvolvimento de tecnologias para perfuração de poços em condições severas de pressão e temperatura está ligado aos fluidos de perfuração. O entendimento do comportamento da mistura de fluido de perfuração e gás da formação, numa situação de influxo de gás da formação para o poço (kick), é essencial para as operações de controle de poço. Especialmente quando se utilizam fluidos orgânicos, os quais dificultam a detecção do influxo. O principal objetivo do presente trabalho é o estudo do comportamento termodinâmico desses fluidos a condições compatíveis com as de fundo de poços de alta temperatura e alta pressão (ATAP). Para atingir esta meta utilizou-se uma célula PVT com limite operacional de 200°C e 100MPa. Primeiramente estudou-se o sistema metano/nparafina nas composições de 0 a 95% em fração molar de metano e nas temperaturas de 70°C a 130°C. Numa segunda fase do trabalho foi estudado o sistema metano/emulsão com duas composições de emulsões, uma 60% n-parafina e outra 70%, variando-se também fração de gás e temperatura. Através dos dados experimentais do sistema metano/n-parafina realizou-se modelagem computacional para o cálculo da solubilidade, densidade e fator volume de formação, obtendo-se correlações que permitiram avaliar projeções baseadas na hipótese da aditividade. Para o cálculo direto dessas propriedades obtiveram-se correlações para o sistema metano/emulsões, as quais foram empregadas em cálculos de volume ganho no tanque como exemplo de sua aplicabilidade
Abstract: One of the advances in the development of drilling technologies under severe conditions of pressure and temperature is related to the drilling fluids. The understanding of the behavior of drilling fluid and the formation gas mixture, in a kick situation, is essential for the well control operations. Especially when organic fluids are used, which makes it more difficult to detect the influx of gas from the formation into the well. The main objective of this work was the study of the PVT behavior of these fluids at pressures and temperatures consistent with the HTHP well conditions. In order to accomplish that, a PVT cell with an operational limit of 200°C and 100MPa was used. First the system methane/n-paraffin was studied, with compositions from 0 to 95% in molar fraction of methane and at temperatures from 70 to 130°C. In a second phase of this work the system methane/emulsion was studied, for two different emulsions, one with 60% n-paraffin and another with 70%, also varying gas fraction and temperature. Through the experimental data of the methane/n-paraffin system a computational modeling was conducted to calculate solubility, density and formation volume factor, resulting in correlations that enabled the evaluation of the validity of the additivity hypothesis. For the entire experimental parameters spam, mathematical adjustments of the methane/emulsion system were done. This correlations were used in pit gain calculations as an example of its applicability
Mestrado
Explotação
Mestre em Ciências e Engenharia de Petróleo
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Bayagbon, Anthony Mamurhomu. "Impact assessment of the environmental protection policies in the upstream oil industry in Nigeria / A.M. Bayagbon." Thesis, North-West University, 2011. http://hdl.handle.net/10394/6276.
Full textAbstract:
The need for energy and the associated economic benefits from the oil and gas deposits found mainly in
the Niger Delta region of Nigeria necessitated the exploration and exploitation activities being carried
out by the oil and gas Companies. However, these exploration and exploitation activities due to their
unpredictable nature have a huge potential for environmental pollution as been experienced in the form
of oil spills, gas flaring, irresponsible disposal of waste and several other activities that have resulted in
the environmental degradation of the Niger Delta region.
In the light of these, the Federal Government of Nigeria having experienced the consequences of
pollution of the environment during the Koko Toxic Waste Dump incident in the then Bendel State in
1987 established a regulatory body tasked with the responsibility of harmonizing the economic interest
from the oil and gas exploration and exploitation activities with the sustainability of the natural
environment by developing well structured and articulated policies aimed at guiding the operations of
the oil and gas operators, track their compliance and administer appropriate punitive measures for non
compliance.
However, this research work which is aimed at evaluating the impact of the environmental protection
policies in upstream oil and gas activities in the Niger Delta region, involved the use of questionnaires
and interviews. These questionnaires were completed by the management and staff of three major oil
and gas companies operating within the area, the Department of Petroleum Resources and members of
the Host communities. The interview was carried out to provide relevant feedback on their assessment
of the impact made by the environmental protection policies on the upstream oil and gas activities in
their operational areas/host communities.
The study however concluded that “Although there is a regulatory body tasked with the responsibility to
develop, implement and track compliance of the environmental protection policies in the upstream oil
industry, the body is ineffective and as such the impact of the environmental protection policies is
inadequate.
Appropriate informed recommendations on the improvement strategies to the identified gaps that
resulted in the unfavorable conditions were also provided.Thesis (M.Ing. (Development and Management Engineering))--North-West University, Potchefstroom Campus, 2011
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Vaqueiro, Ricardo Luiz de Campos. "\"Avaliação do potencial de contaminação de aqüíferos porosos a partir da perfuração de poços de petróleo utilizando fluído n-Parafina\"." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/44/44138/tde-16032007-163331/.
Full textAbstract:
Na perfuração de poços para extração de petróleo são utilizados fluidos de perfuração compostos por diversos produtos químicos com finalidades específicas em função das características de cada poço. Durante vários anos utilizou-se fluido a base de óleo diesel, devido à excelente performance proporcionada à perfuração. O aumento da preocupação ambiental levou a indústria do petróleo a elaborar composições de fluidos que fossem menos agressivas ao ambiente e, ao mesmo tempo, apresentassem performances semelhantes à do fluido base óleo diesel, destacando-se na atividade de perfuração na bacia do Recôncavo, Bahia, o fluido n-Parafina. Entre os compostos de interesse ambiental presente neste tipo de fluido, destacam-se a n-Parafina e cloretos, algumas vezes com traços de BTEX (benzeno, tolueno, etilbenzeno e xilenos). Como durante a perfuração podem ser atravessados aqüíferos portadores de água doce, resta a preocupação de que o contato desses fluidos com estes aqüíferos possa gerar problemas de contaminação ambiental. Este trabalho apresenta uma avaliação de situações de poços, onde o aqüífero São Sebastião, principal da bacia do Recôncavo, foi atravessado utilizando-se fluido n-Parafina. A avaliação foi baseada em simulações matemáticas do transporte dos compostos encontrados no fluido n-Parafina e em amostras coletadas a partir de testes de formação a cabo durante a perfuração dos poços. A partir da simulação destes valores reais, pôde-se concluir que, a menos de 0,5 m da parede dos poços, as concentrações encontram-se perfeitamente dentro dos padrões de potabilidade para todos os compostos analisados. De acordo com a metodologia utilizada, as utilizações do fluido n-Parafina são ambientalmente inofensivas como fluido de perfuração a ser utilizado neste tipo de cenário hidrogeológico.The use of drilling fluids or muds is standard practice in oil industry. The composition of these fluids is designed according to the formation and the well properties. For many years oil- based muds (OBM) had a worldwide use because they offered advantages over water-based muds (WBM). Increasing environmental concern led the oil industry into the formulation of a variety of syntetic organic based mud (SBM) or low-tox mineral oil- based mud, like the n-parafin based mud, with a large use at the Reconcavo Basin, Bahia, Brazil. Some of the compounds that are common to most fluid formulas are considered potential environmental contaminants, among them n-parafin and chloride, sometimes with trace BTEX (benzene, toluene, ethylbenzene and xylenes). The drilling of the well might cross aquifers that are used for drinking purposes before reaching the oil reservoir and the contact of the water with the drilling fluid might pose some concern about the aquifer contamination. This paper presents case studies where a well penetrated São Sebastião Aquifer, in Reconcavo Basin, using n-Parafin based mud and a mathematical model was applied to simulate the fate and transport of the compounds found in fluid and samples collected during the drilling. The results indicated that all concentration values of the detected compounds were well below water drinking standards within 0,5 m from the well. According to this conclusion, the use of the n-parafin fluid is considered harmless to the environment and is recommended for similar geological scenarios.
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Salmazo, Eduardo 1980. "Modelagem matemática da evolução de domos salinos sua influência na perfuração de poços de petróleo." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263224.
Full textAbstract:
Orientador: José Ricardo Pelaquim MendesDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de Geociências
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Resumo: Neste trabalho discute-se os desafios associados à atividade de perfuração de poços de petróleo através de formações afetadas pela presença de domos salinos. Domos salinos podem induzir grandes tensões nas formações subjacentes e adjacentes, impondo a necessidade de um planejamento específico para a perfuração e manutenção de poços de petróleo. Durante a perfuração, em frente à zonda de sal, há relatos de problemas de aprisionamento de coluna, dissolução de sal no fluido de perfuração, ocasionando a formação de batentes mecânicos e cavernas. Há ainda, nas formações que rodeiam um domo salino, devido à alterações no campo de tensões, problemas de instabilidade nas paredes do poço aberto e formação de zonas anormalmente prossurizadas. Após o revestimento do poço, há casos de colapso do revestimento. Para prever e mitigar os riscos associados à essa atividade é de fundamental importância o entendimento dos fenômenos físicos que o ocasionam. Com essa finalidade, foi feito um estudo à respeito de tais mecanismo físicos como fluência e instabilidade hidrodinâmica, mais especificamente a instabilidade de Rayleigh-Taylor. Desenvolveu-se, a partir de tal estudo, um modelo analítico para prever o desenvolvimento de um domo salino e discutiu-se a forma como este pode interferir em parâmetros importantes para a atividade de perfuração como, por exemplo, o campo de tensões nas formações adjacentes às camadas de sal
Abstract: In this present work are discussed the challenges associated with the drilling activities in oil wells through formations affected by the presence of salt domes. This geological structures can induce large stresses in the underlaying and adjacent formations, imposing the necessity of specific planning for drilling and maintenance of such oil wells. During drilling, facing the salt, there are reports of problems of stuck pipe, salt dissolution, forming mechanical stops and caves. There are still, in formations around a salt dome, due changes in the stress field, problems of well instability and abnormally pressure zones. After casing, there are cases of case collapse. To prevent and mitigate risks associated to this activity, is crucial understand the physical phenomena behind it. With such finality, was made an study related with such physical mechanisms, such hydrodynamic instability, specifically the Rayleigh-Taylor instability. Was developed, from this study, an analytical model to predict the salt dome development and was discussed the way such it can interfer in important paramenters related to the drilling activity as, for exemple, the tension field in the formation around the salt dome
Mestrado
Explotação
Mestre em Ciências e Engenharia de Petróleo
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Токарев, М. А., and Н. М. Токарева. "Моделирование геолого-технических условий разработки нефтяных месторождений с целью выбора положения боковых стволов скважин." Thesis, Сумский государственный университет, 2014. http://essuir.sumdu.edu.ua/handle/123456789/39358.
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Silva, Luciano da. "Análise modal e controle de plataformas offshore sujeitas a perturbações persistentes." Pós-Graduação em Engenharia Elétrica, 2014. https://ri.ufs.br/handle/riufs/5020.
Full textAbstract:
A exploração offshore tem crescido muito nos últimos anos e grandes estruturas e equipamentos têm sido projetados e construídos para remover o óleo que se encontra abaixo da superfície do mar. Para plataformas offshore fixas tipo jaqueta é necessário analisar os problemas decorrentes da exposição dessas instalações ao ambiente hostil do oceano. Estas perturbações induzem vibrações excessivas nas estruturas, afetando o conforto e a estabilidade da instalação, e para combater essas vibrações uma ferramenta matemática foi utilizada para monitorar o estado da integridade da estrutura, a
Transformada de Hilbert-Huang (HHT). O HHT foi utilizada com sucesso para a identificação de parâmetros modais, como frequência fundamental e fator de amortecimento da plataforma. Finalmente, uma técnica de controle de vibração ativa baseada no Controle Linear Quadrático (LQ) é implementada com o objetivo de reduzir os efeitos de perturbações oscilatórias indesejáveis causados por ondas e correntes marinhas.The offshore exploration has grown tremendously in recent years, and large structures and equipment has been designed and built to remove the oil that lies beneath the sea surface. For fixed jacket type offshore platforms is necessary to consider the problems arising from exposure of these facilities to the hostile ocean environment. These perturbations induce excessive vibrations in the structures affecting the comfort and stability of the facility, and for to combat these vibrations a mathematical tool was used to monitor the integrity health of the structure, namely the Hilbert-Huang Transform (HHT). The HHT was used for the successfully identification of modal parameters, as fundamental frequency and damping factor of the platform. Finally, an active vibration control technique based on the Control Linear Quadratic (LQ) is implemented aiming to reduce the effects of undesirable oscillatory perturbations caused by waves and marine current.
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Alegria, Luis Miguel Casanova. "Soluções analíticas e numéricas para o escoamento laminar desenvolvido de fluído viscoplástico em dutos e anulares elípticos." Universidade Tecnológica Federal do Paraná, 2011. http://repositorio.utfpr.edu.br/jspui/handle/1/350.
Full textAbstract:
Durante o processo de perfuração de poços de óleo e gás, em geral a passagem e oscilações da broca de perfuração provoca a ovalização das paredes do poço. O presente trabalho apresenta um estudo analítico e numérico do escoamento de fluido viscoplástico tipo Herschel-Bulkley através de três configurações de tubos de seções transversais elípticas: tubo elíptico, elíptico anular concêntrico e excêntrico. O objetivo desse estudo é analisar o efeito dos parâmetros geométricos do tubo, cinemáticos do escoamento e reológicos do fluido na perda de carga. A modelagem matemática foi realizada com base nas equações de balanço de massa e de quantidade de movimento e uma equação constitutiva para o tensor tensão do fluido. Para a solução analítica são utilizados os métodos de transformação de coordenadas e da folga variável modelando o escoamento como entre placas paralelas. Para a solução numérica é empregado o método de volumes finitos. As simulações numéricas são realizadas com o programa comercial PHOENICS-CFD. Para validar os resultados, são realizadas comparações com a literatura. Para cada geometria investigada foram obtidos os parâmetros de interesse na engenharia como: perfil de velocidade, vazão volumétrica, perfil das tensões e expressão para o fator de atrito. Os resultados para o duto anular circular concêntrico e excêntrico são corretamente reproduzidos quando a seção anular elíptica tende para a razão de aspecto unitária.During the oil well drilling operations, the oscillations and the advancement of the drill makes the well takes an oval shape. This work presents an analytical and numerical study of the viscoplastic fluid flow of a Herschel-Bulkley fluid, through three types of elliptical cross sections ducts: elliptical, concentric and eccentric elliptical annulus. The objective is to analyze the effects of the pipe geometrical parameters, the kinematics of the flow and the fluid rheology over the pressure drop. The mathematical model was based on the mass and momentum balance equations and a constitutive equation expressing the stress tensor of the fluid. The analytical solutions employed were an analytical transformation of coordinates and other one based on in the slot flow model and the fluid flow was modeled as parallel plates in narrow annuli. For the numerical solution of the balance equations the finite volume method was used. The numerical simulations were carried out with PHOENICS-CFD. For validation of the results, comparisons with numerical and analytical results available in literature were done. Relevant engineering parameters were obtained, like velocity profiles, volumetric flow rate, shear stress profiles and an expression for the friction factor. The results for the concentric and eccentric circular annulus are adequately reproduced when the elliptical cross section tends towards unitary aspect ratio.
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Paula, Junior Rubens Ribeiro de. "Modelagem de controle de poço com fluidos de perfuração não aquosos e estudos de casos." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263123.
Full textAbstract:
Orientador: Paulo Roberto RibeiroDissertação (mestrado) - Universidade Estadual de Campinas. Faculdade de Engenharia Mecanica e Instituto de Geociencias
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Resumo: O trabalho apresenta uma revisão da literatura sobre poços HPHT, abordando o desafio na construção dos mesmos, com ênfase no aspecto de segurança de poço. Do ponto de vista de desenvolvimento, o trabalho envolveu a implementação de um modelo de controle de poços com fluidos de perfuração não aquosos em software existente (Unikick), que incorpora correlações empíricas derivadas de resultados experimentais com n-parafina e diesel. A importância dessa implementação deve-se ao fato de que a previsão do comportamento das pressões, vazões e volumes desenvolvidos em um poço durante a detecção e circulação de um kick de gás, é muito útil para o engenheiro de perfuração que poderá tomar decisões sobre a maneira mais segura de lidar com estas situações. Alguns estudos de casos foram realizados através de comparação dos resultados obtidos pelo Unikick e outros simuladores disponíveis e análise de sensibilidade de parâmetros. Nessa análise, foram simuladas circulações de kicks em terra e marítimos em várias lâminas d'água, com trajetórias verticais e horizontais e observados os comportamentos de parâmetros importantes durante o controle do poço, como a pressão no choke, pit gain e vazão de gás na superfície.
Abstract: The first part of the work provides a review of the literature on HPHT wells, addressing the challenge in the construction of these wells, emphasizing the safety aspects. From the point of view of development, the work involved an implementation of a well control model for nonaqueous drilling fluids using existing software (Unikick), that incorporates empirical correlations derived from experimental results with n-paraffin and diesel. The importance of this implementation is due to the fact that the estimation of the behavior of pressures, flow rates and volumes developed inside a well during gas kick detection and circulation out of the well is very useful for the drilling engineer to take decisions about the safest way to handle these situations. Some case studies were performed through the comparison of simulated results from Unikick and other simulators available and a sensitivity analysis. In this analysis, some kick circulations were simulated in onshore and offshore wells with various water depths, vertical and horizontal trajectories, when important parameters of well control were observed, such as choke pressure pit gain and gas flow rate at surface.
Mestrado
Explotação
Mestre em Engenharia Mecânica
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Romanó, James Luigi. "Modelo numérico para determinação de zonas de perda de circulação de fluido de perfuração em poços de petróleo." Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/2631.
Full textAbstract:
Durante a perfuração de poços de petróleo, a determinação do perfil de temperaturas no poço é importante para tomada de decisões relativas ao processo de cimentação, para a seleção de revestimento do poço e equipamentos e, sobretudo, na identificação de zonas de influxo e perda de circulação. Neste trabalho é proposto um modelo matemático da transferência de calor em regime transitório do escoamento de fluido de perfuração em poços fraturados com perda de circulação. O poço é representado de maneira simplificada através de um cilindro anular concêntrico, cuja parede externa (interface poço-formação) apresenta uma ou mais fraturas discretas. Para a obtenção do modelo térmico é realizado um balanço de energia com foco nas trocas de calor entre a coluna de perfuração, região anular e formação rochosa. A característica principal do modelo proposto é a possibilidade de detecção da posição e número de fraturas a partir do perfil do gradiente térmico da região anular ao longo poço. Para tanto, com o código numérico, obtido via método dos volumes finitos, investiga-se a influência de parâmetros: da fratura (profundidade relativa, perda de circulação, número e distância entre fraturas), físicos (tempo de circulação) e do regime de escoamento (número de Reynolds e viscosidade dos fluidos de perfuração). As variáveis-resposta principais analisadas são a temperatura da região anular e o gradiente térmico. Como variáveis-resposta secundárias são utilizadas as evoluções térmicas da temperatura no fundo do poço e na saída da região anular. É constatado que o aumento da profundidade relativa ou número de fraturas diminui a temperatura do fundo do poço, sem causar variação significativa na temperatura de saída do anular. Para a variação da perda de circulação, o efeito na temperatura do fundo do poço é similar ao da variação do aumento da profundidade relativa da fratura, no entanto são observadas diferenças na temperatura de saída. Além disso, é verificado que, conforme se aumenta o número de fraturas distribuídas ao longo da profundidade do poço, a temperatura do poço tende ao caso de poço não fraturado. De maneira similar é evidenciada a tendência de que a diminuição na distância entre fraturas se aproxima dos resultados para um poço com uma única fratura. Finalmente, o aumento da perda de circulação facilita a detecção de fraturas devido a respectiva mudança na descontinuidade do perfil do gradiente térmico da região anular.During oil drilling operations, the wellbore temperature profile is used when selecting well casing materials, making cementation related decisions, and, most importantly, to identify loss zones. In this work, a transient heat transfer mathematical model for a fractured wellbore is proposed. The well has its geometry simplified to a concentric annular cylinder which has one or more discrete fracture in its external wall (wellformation interface). In order to obtain the thermal model an energy balance is used, focusing the heat transfer between the pipe, the annular region and the formation. The key characteristic of the model is the fracture detection through thermal gradient graphical analysis. The thermal gradient is an output of the solution of the discretized energy equation in the domains, obtained through the finite volume method. The following parameters are investigated: fracture depth, fracture number, fracture interference, loss circulation, circulation time, Reynolds number and drilling fluid viscosity. The analysis is done through the analysis of the annular region temperature profile and its gradient, along with the thermal evolution of both the bottomhole and outlet temperatures. It is verified that increasing the fracture relative depth or number decreases the bottomhole temperature, while having no significant impact in the outlet temperature. The same bottomhole temperature effect is noted when increasing loss rate, however outlet temperature changes are observed. In a similar way, when decreasing the distance between fractures, the temperature profile in the annular region trends to a wellbore with a single fracture. Finally, increasing loss rate favors fracture detection, since the discontinuity in the annular region thermal gradient profile is intensified.
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Galdino, Jonathan Felipe. "Modelagem da propagação de pressão em fluidos de perfuração durante kick de gás." Universidade Tecnológica Federal do Paraná, 2016. http://repositorio.utfpr.edu.br/jspui/handle/1/2663.
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PetrobrasNo processo de perfuração de poços de petróleo e gás o controle da pressão é uma importante tarefa. Se a pressão no interior do poço estiver abaixo da pressão de poros, um influxo da formação pode ocorrer, fenômeno denominado de kick. Se o influxo não for controlado pode ocorrer um fluxo descontrolado da formação para a superfície (blowout). As pressões de fechamento são utilizadas para calcular a pressão do reservatório, entretanto, o caráter viscoplástico do fluido de perfuração atenua as pressões medidas. No presente trabalho, é apresentada uma modelagem matemática e numérica para prever a propagação de pressão ao longo do poço durante um influxo de gás (kick). Considerou-se a compressibilidade e o comportamento viscoplástico do fluido de perfuração, modelando-o como Plástico de Bingham. O escoamento é considerado unidimensional, laminar, transiente, isotérmico e homogêneo. A solubilidade do gás no fluido de perfuração é desconsiderada e o gás é modelado como um gás real. O fluxo da formação para o interior do poço é tratado através da lei de Darcy. Os balanços de massa e de quantidade de movimento para a mistura formam um sistema de equações diferenciais parciais hiperbólicas, tendo como incógnitas a pressão e a velocidade, as quais são resolvidas pelo método das características. Consideram-se dois casos de estudo: o kick dinâmico e o kick estático. A obtenção dos campos de velocidade e pressão ao longo do poço é realizada através de um programa computacional desenvolvido em linguagem FORTRAN. Posteriormente, aferiu-se os resultados obtidos pelo modelo desenvolvido comparando-os com solução analítica e dados experimentais. Os resultados apresentam que quanto maior a tensão limite de escoamento, menor é a transmissão de pressão e que se a pressão do reservatório não for grande o suficiente, não há ganho de volume de fluido nos tanques de lama.
In the process of drilling oil and gas wells the pressure control is an important task. If the pressure inside the well is smaller than the formation pressure, an influx of the formation may occur, phenomenon denominated as kick. If the influx is not controlled there may be an uncontrolled flux from the formation to the surface (blowout). The closing pressures are used to calculate the formation pressure, however, the viscoplastic character of the drilling fluid reduces the pressures measured on the surface. This current work presents a mathematical and numerical modeling to predict the pressure propagation along the well during a gas influx (kick). The compressibility and the viscoplastic behavior of the drilling fluid were considered, modeling it as a Bingham Plastic. The flow is considered as one-dimensional, laminar, transient, isothermal and homogeneous. The solubility of the gas in the drilling fluid is disregarded and the gas is modeled as a real gas. The flux of the formation into the wellbore is treated by Darcy’s law. The balance equations of mass and momentum for the mixture result in a system of hyperbolic partial differential equations, having as unknowns the pressure and the velocity, which are solved by the method of characteristics. Two study cases were considered: the dynamic kick and the static kick. The pressure and velocity fields along the well are obtained by a computer program developed in FORTRAN language. Afterwards, the results obtained from the model developed were assessed by comparing to analytic solution and experimental data. The results present that the bigger the yield stress is, the smaller is the pressure transmission and that if the formation pressure is not high enough, there is no pit-gain in the mud tanks.
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Ribeiro, Vaniele Souza. "Caracterização de águas produzidas provenientes de campos petrolíferos onshore do Estado de Sergipe." Pós-Graduação em Química, 2013. https://ri.ufs.br/handle/riufs/6117.
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In this work, five water produced samples from oil fields onshore (land) of the Sergipe State were characterized. The physico-chemical parameters such as pH, conductivity, turbidity, suspended solids, biochemical oxygen demand (BOD) and content of oil and grease (TOG) were determined. The concentrations of anions (Br-, Cl-, F-, NO3- and SO42-) and cations (Ca2 +, K +, Mg2+, Na +, and NH4+) were determined by ion chromatography (IC). The total arsenic was determined by hydride generation atomic fluorescence spectrometry (HG AFS). For trace metals determination (Ba, Cd, Cr, Cu, Fe, Li, Mn, Ni, Pb, V and Zn) was used inductively coupled plasma mass spectrometry (ICP-MS). The limit of quantification (LOQ) ranged between 0.07 ìg L-1 (Cd e V) and 22 ìg L-1 (Fe). The precision was expressed as relative standard deviation (RSD) ranged between 0.03% (Na+) and 7.39% (F-). The values of recoveries obtained were between 85 ± 3% (Zn) and 112 ± 1% (Li). The results were compared to the values established by Resolution 430/2011 of the National Council for the Environment (CONAMA). To evaluate the data, the principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used. The concentrations of BOD, TOG, Ba, Mn and Fe were higher than those allowed by law, for some samples. The pH and concentration of As, Pb, Cr, Cu and Ni, for all samples, were consistent with established values. The conductivity, turbidity, suspended solids, concentration of anions, cations, Li and V are not required by law. The concentrations of Cd and Zn were below the LOQ of the method. In general, all the samples have very similar profiles with relatively close found values for all parameters. It was found that the samples have characteristics and inorganic constituents, which may cause damage to environment or generate drawbacks when used for reinjection. Therefore, the monitoring and characterization the produced water from onshore oil fields are very important for proper treatment of this effluent.Neste trabalho, foram caracterizadas cinco amostras de agua produzida, provenientes de campos petroliferos onshore (terrestres) do Estado de Sergipe. Foram determinados os parametros fisico-quimicos, como pH, condutividade, turbidez, solidos suspensos, demanda bioquimica de oxigenio (DBO) e teor de oleos e graxas (TOG). Os anions (Br- , Cl-, F-, NO3- e SO42-) e cations (Ca2+, K+, Mg2+, Na+ e NH4+) foram determinados por cromatografia de ions (IC). O arsenio total foi determinado por espectrometria de fluorescencia atomica com geracao de hidreto (HG AFS). Para determinacao dos metais traco (Ba, Cd, Cr, Cu, Fe, Li, Mn, Ni, Pb, V e Zn) foi utilizada a espectrometria de massa com plasma indutivamente acoplado (ICP-MS). Os valores de limite de quantificacao (LQ) variaram entre 0,07 Êg.L-1 (Cd e V) e 22 Êg.L-1 (Fe). A precisao foi expressa como desvio padrao relativo (RSD), variando entre 0,03% (Na+) e 7,39% (F-). Os valores de recuperacoes ficaram entre 85 } 3 % (Zn) e 112 } 1% (Li). Os resultados obtidos foram comparados aos valores estabelecidos pela Resolucao 430/2011 do Conselho Nacional de Meio Ambiente (CONAMA). Para avaliar os dados, utilizou-se a analise de componente principal (PCA) e analise de agrupamento hierarquico (HCA). Os valores das concentracoes de DBO, TOG, Ba, Mn e Fe foram maiores do que os permitidos pela legislacao, para algumas amostras. Os valores de pH e constituintes inorganicos (As, Pb, Cr, Cu e Ni) para todas as amostras foram concordantes com os valores estabelecidos. A condutividade, turbidez, solidos suspensos, concentracao de anions, cations, Li e V ainda nao sao previstos por lei. Os valores de concentracao de Cd e Zn ficaram abaixo do LQ do metodo. No geral, todas as amostras possuem perfis bem semelhantes, com valores encontrados relativamente proximos para todos os parametros. Foi constatado que as amostras possuem caracteristicas e constituintes inorganicos, que podem causar danos ao meio ambiente ou gerar empecilhos quando utilizadas para fins de reinjecao. Portanto, o monitoramento e caracterizacao das aguas produzidas provenientes de campos petroliferos onshore sao de grande importancia para o tratamento adequado deste efluente.
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Ferreira, Cl?vis Dantas. "Novo m?todo para estimativa do gradiente de fratura para po?os de petr?leo." Universidade Federal do Rio Grande do Norte, 2010. http://repositorio.ufrn.br:8080/jspui/handle/123456789/13006.
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Previous issue date: 2010-08-13The development of oil wells drilling requires additional cares mainly if the drilling is in offshore ultra deep water with low overburden pressure gradients which cause low fracture gradients and, consequently, difficult the well drilling by the reduction of the operational window. To minimize, in the well planning phases, the difficulties faced by the drilling in those sceneries, indirect models are used to estimate fracture gradient that foresees approximate values for leakoff tests. These models generate curves of geopressures that allow detailed analysis of the pressure behavior for the whole well. Most of these models are based on the Terzaghi equation, just differentiating in the determination of the values of rock tension coefficient. This work proposes an alternative method for prediction of fracture pressure gradient based on a geometric correlation that relates the pressure gradients proportionally for a given depth and extrapolates it for the whole well depth, meaning that theses parameters vary in a fixed proportion. The model is based on the application of analytical proportion segments corresponding to the differential pressure related to the rock tension. The study shows that the proposed analytical proportion segments reaches values of fracture gradient with good agreement with those available for leakoff tests in the field area. The obtained results were compared with twelve different indirect models for fracture pressure gradient prediction based on the compacting effect. For this, a software was developed using Matlab language. The comparison was also made varying the water depth from zero (onshore wellbores) to 1500 meters. The leakoff tests are also used to compare the different methods including the one proposed in this work. The presented work gives good results for error analysis compared to other methods and, due to its simplicity, justify its possible application
O desenvolvimento da perfura??o de po?os de petr?leo requer cuidados adicionais principalmente se a perfura??o for mar?tima em l?mina d ?gua ultraprofunda, o que levam a baixos gradientes de sobrecarga, ocasionando baixos gradientes de fratura e, conseq?entemente, dificultando as opera??es de perfura??o pela redu??o da janela operacional. Para minimizar as dificuldades enfrentadas pela perfura??o nesses cen?rios, na fase de planejamento, s?o utilizados modelos indiretos para estimativa do gradiente de fratura, que podem prev? valores aproximados dos testes de absor??o. Esses modelos geram perfis de geopress?o que permitem a an?lise detalhada do comportamento das press?es em todo o intervalo do po?o. A maioria dos modelos tem como base a equa??o de Terzaghi, diferenciando apenas na determina??o dos valores do coeficiente de tens?o da matriz da rocha. Este trabalho prop?e uma forma alternativa diferente, para se estimar o gradiente de fratura, por meio de uma correla??o geom?trica que relaciona proporcionalmente os gradientes de press?o para cada profundidade em todo o intervalo do po?o. As grandezas envolvidas variam em uma mesma propor??o em todo intervalo do po?o. O modelo baseia-se na aplica??o da propor??o ?urea do segmento sobre o diferencial de press?o correspondente ? tens?o da matriz. O estudo mostra que a propor??o ?urea encontra valores de gradiente de fratura com grande aproxima??o dos valores de testes de absor??o dispon?veis da ?rea. Os resultados obtidos foram comparados com doze modelos indiretos distintos que estimam gradiente de fratura baseados no efeito da compacta??o. Para isto, um programa em linguagem Matlab foi desenvolvido. A compara??o tamb?m foi feita com a varia??o de l?minas d ?gua variando de zero (para po?os terrestres, por exemplo) a 1500 m. A medida da precis?o para avalia??o de cada m?todo toma como referencial os valores de testes de absor??o e ? feita atrav?s do erro relativo percentual. A precis?o mostrada nos valores apresentados na an?lise de erro e a forma bastante simples do modelo proposto mostram que ? justific?vel a sua aplica??o
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BELCHIOR, INGRID MILENA REYES MARTINEZ. "NUMERICAL MODELING OF ROCK CUTTING PROCESS FOR DRILLING OIL WELLS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2012. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=20363@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
O mecanismo de corte em rocha é determinante na eficiência do processo de perfuração de poços de petróleo. Este mecanismo tem sido estudado através de ensaios de corte com um único cortador. Neste trabalho foram desenvolvidos modelos com o método dos elementos finitos para simular o processo de corte em rocha realizado por um cortador único. Este trabalho está vinculado ao Projeto de Modelagem de Perfuração de Evaporitos sob Altas Pressões desenvolvido pela Baker-Hughes e o Grupo de Tecnologia em Engenharia de Petróleo (GTEP) da PUC-Rio. As simulações numéricas foram feitas utilizando-se o programa ABAQUS. O modelo constitutivo de Drucker-Prager foi descrito e usado para modelar o comportamento da rocha. O modelo de dano isotrópico foi usado para modelar a erosão do material produzida na interação rocha-cortador. Os resultados das simulações com modelos bidimensionais e tridimensionais permitiram analisar a influência da variação da profundidade de corte e da pressão de confinamento na energia específica necessária para realizar o corte em rocha. Observou-se que, até certo limite, quanto mais profundo estiver o cortador menor energia específica será necessária para o corte. A análise da influência da pressão de confinamento mostrou que o corte de rocha em condições atmosféricas fornece valores de energia específica muito próximos à resistência à compressão não confinada da rocha, enquanto que a aplicação de pressão confinante causa incrementos da energia específica.
The understanding of rock cutting mechanism is critical to the efficiency of borehole drilling process. This mechanism is studied through single cutter tests. In this work were developed models with the Finite Element Method to simulate the rock cutting process by a single cutter. This work is connected to the project Modeling of Evaporite Drilling Under High Pressure, sponsored by Baker Hughes in partnership with the Group of Technology and Petroleum Engineering (GTEP) of the Pontifical Catholic University of Rio de Janeiro. The numerical simulations were performed using the program ABAQUS. The Drucker- Prager constitutive relationship was used to model the rock behavior. Also, an isotropic model of damage was described and employed for modeling the erosion mechanism that represents the rock-cutter interaction. Two and three-dimensional simulations allowed the analysis of the influence of the variation of cutting depth and confining pressure on the mechanical specific energy required to cut the rock. To certain depth limit, it was observed that for larger depths of cut, less specific energy is required to cut the rock. The analysis of experiments under confining pressure showed that cutting process under atmospheric conditions produced specific energy close to the unconfined compressive strength of rock, while the application of confining pressure showed a remarkable increase in specific energy required for cutting.
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FERNANDES, ANDRE ALONSO. "MODELING AND NONLINEAR CONTROL EVALUATION FOR MANAGED PRESSURE DRILLING OF OIL WELLS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2015. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=25706@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROPara acesso aos reservatórios portadores de hidrocarbonetos é necessária a perfuração de poços de petróleo. Entre as várias funções do fluido de perfuração podem se destacar o transporte do cascalho gerado pela broca, a função de primeira barreira para inibição de influxo das formações expostas no poço e a manutenção da pressão do poço dentre os limites de resistência das formações atravessadas (janela operacional). Alguns novos campos petrolíferos, bem como campos depletados sofrem restrições operacionais devido a pequenas janelas operacionais. A variação da pressão no poço aberto devido a perdas por atrito no anular, em alguns casos é maior do que a janela operacional, impedindo a perfuração do poço. Managed Pressure Drilling (MPD) é uma tecnologia alternativa à perfuração convencional. O anular do poço é vedado, possibilitando a retenção de pressão no anular. O ajuste da pressão no anular do poço possibilita compensar a variação da perda de atrito e perfurar poços com janelas operacionais estreitas. Para manutenção da pressão da zona objetivo dentro da janela operacional é necessário o controle adequado da pressão na superfície. A definição do valor de pressão necessário é obtida através do conhecimento do comportamento da dinâmica do fluido de perfuração no poço. Este trabalho desenvolveu um modelo de um sistema de poço de petróleo com MPD, levando em conta os efeitos estáticos e dinâmicos envolvidos na perfuração MPD. Sobre o modelo desenvolvido foram propostas e aplicadas diferentes técnicas de controle linear e não-linear para avaliação do desempenho dos controladores e identificação de pontos-chave na aplicação da técnica MPD. Os controles nãolineares propostos foram bem sucedidos em compensar os efeitos altamente nãolineares do sistema, melhorando sua resposta em tarefas típicas.
For access of hydrocarbon reservoirs, drilling oil wells is required.. Among the various functions the drilling fluid may provide are cutting transportation generated by the bit, a barrier function for inhibiting influx of exposed formations in the well and maintaining well pressure within the resistance limits of the formations exposed (operational window). Some new oil fields as well as some depleted fields are experiencing severe operational restrictions due to small operational windows. The open hole pressure variation due to friction losses on the annular in some cases is greater than the operational window, inhibiting the perforation of the well. Managed Pressure Drilling (MPD) is an alternative technology to conventional drilling. The annular of the well is sealed while pressure is contained within it. By adjusting annular pressure it is possible to compensate for friction loss variation on the annular and drill well sections with close operational windows. For the proper pressure maintenance on the target zone within the operating window, it is required adequate pressure control on the surface. The definition of the necessary pressure value is obtained through knowledge of the dynamic behavior of the drilling fluid in the well. This work has developed a model of an oil well system with MPD, taking into account the static and dynamic effects involved in MPD. To the developed model different linear and non-linear control techniques were proposed and applied for evaluating the performance of controllers and identifying key points in implementing the MPD technique. The proposed non-linear control techniques were able to compensate for the highly non-linear nature of the system, improving its response during typical tasks.
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Manzatto, Leopoldo Marques. "Análise dinâmica de colunas de perfuração de poços de petróleo usando controle linear de velocidade não-colocalizado." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/18/18149/tde-27072011-184508/.
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Este trabalho apresenta uma análise paramétrica da reposta dinâmica de colunas de perfuração de poços de petróleo com controle proporcional-integral de velocidade não colocalizado. A operação de perfuração de poços de petróleo e gás em águas profundas consiste na abertura de poços em solo rochoso através de uma broca cuja rotação é controlada por uma mesa rotativa na superfície. O torque imposto pela mesa é transmitido à broca por meio de uma coluna de perfuração. Particularmente no caso de perfuração em águas profundas, as colunas de perfuração podem ser muito extensas e, portanto, bastante flexíveis. As vibrações ocasionadas pela grande flexibilidade das colunas de perfuração são as principais responsáveis por falhas no processo de perfuração. Em particular, o fenômeno não-linear conhecido como stick-slip e relacionado às vibrações torcionais da coluna de perfuração, faz com que um sistema de controle projetado para manter a velocidade da mesa constante dê origem a grandes oscilações na velocidade da broca. Na prática, este fenômeno é amplificado pela inerente não-linearidade do contato entre broca e formação rochosa e pela forte não colocalização entre mesa rotativa e broca. Este trabalho tem por principal objetivo realizar uma análise paramétrica da dinâmica do processo de perfuração, usando um modelo de dois graus de liberdade para representar o conjunto mesa rotativa, coluna de perfuração e broca, para identificar condições nas quais uma lei de controle simples do tipo linear proporcional-integral pode fornecer um desempenho de perfuração estável e satisfatório.This paper presents a parametric analysis of the dynamics of oilwell drillstrings with non-collocated proportional-integral velocity control. The drilling operation for oil and gas in deep waters consists of opening wells in rocky ground formation by a drill, whose angular speed is controlled by a rotary table at the surface. The torque applied by the table is transmitted to the drill-bit through the drillstring. Particularly in the deepwater drilling case, the drillstring can be very long and therefore very flexible. The vibrations caused by the great flexibility of drilling columns are mainly responsible for the failures in the drilling process. In particular, the nonlinear phenomenon known as stick-slip and related to the torsional vibration of the drillstring, makes that a control system designed to maintain a constant angular velocity at the table yield large variations at the drill-bit angular velocity. In practice, this phenomenon is amplified by the inherent nonlinearity of the contact between drill bit and rock formation and by the strong non-colocalization between rotary table and drill-bit. The main objective of this work is to perform a parametric analysis of the dynamics of the drilling process, using a two degrees of freedom model in order to represent the rotary table assembly, the drilling column and drill-bit, to identify conditions in which a simple control law, such as a linear proportional-integral velocity control, can provide a stable and satisfactory drilling performance.
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Monteiro, Hugo Leonardo Salomão. "Análise de desempenho de diferentes leis de controle de vibrações torcionais em colunas de perfuração de poços de petróleo." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/18/18149/tde-26112012-084201/.
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O fenômeno de stick-slip, no processo de perfuração de poços de petróleo, é propiciado pela interação entre broca e formação rochosa e pode dar origem a grandes oscilações na velocidade angular podendo provocar danos irreparáveis ao processo. Neste trabalho, analisa-se o desempenho de leis de controle aplicadas à mesa rotativa (responsável por movimentar a coluna de perfuração), visando à redução de stick-slip e de oscilações da velocidade angular da broca. As leis de controle implementadas são do tipo PI (Proporcional-Integral), com parcelas de torque aplicado à mesa rotativa, proporcional e integral à velocidade da mesa, podendo ser com peso na broca constante ou variável. Para a coluna de perfuração, foi proposto um modelo em elementos finitos com função de forma linear. O torque na broca foi modelado segundo atrito de Coulomb pela forma não regularizada, curva esta ajustada pelos dados empíricos conforme propostas da literatura. Diversos critérios de desempenho foram analisados e foi observado que a minimização do desvio médio da velocidade angular em relação à referência propicia melhores condições de operação. Análises paramétricas dos ganhos de controle proporcional e integral foram realizadas, dando origem a curvas de nível para o desvio médio de velocidade angular na broca. A partir destas curvas, foram definidas regiões de estabilidade nas quais o desvio é aceitável. Estas regiões foram observadas serem maiores para menores pesos na broca e maiores velocidades angulares de referência e vice-versa. A adição do controle do peso na broca permitiu uma redução global dos níveis de desvio médio de velocidade angular, dando origem a um aumento das regiões de estabilidade do processo de perfuração.The stick-slip phenomenon, in the process of drilling oil wells, due to the interaction between drill and rock formation can lead to large fluctuations in drill-bit angular velocity and, thus, cause irreparable damage to the process. In this work, the performance of control laws applied to the rotary table (responsible for moving the drill string) is analyzed, in order to reduce stick-slip and drill-bit angular velocity oscillations. The control laws implemented are based on a PI (Proportional-Integral) controller, for which the torque applied to the rotating table has components proportional and integral to table angular velocity with constant or variable WOB (Weight On Bit). For the drillstring, a finite element model with a linear interpolation was proposed. The torque on the drill-bit was modeled by a non-regularized Coulomb friction model, with parameters that were adjusted using empirical data proposed in literature. Several performance criteria were analyzed and it was observed that the minimization of the mean deviation of the drill-bit angular velocity relative to the target one would provide the best operating condition. Parametric analyses of proportional and integral control gains were performed, yielding level curves for the mean deviation of drill-bit angular velocity. From these curves, stability regions were defined in which the deviation is acceptable. These regions were observed to be wider for smaller values of WOB and higher values of target angular velocity and vice-versa. The inclusion of a controlled dynamic WOB reduced the levels of mean deviation of angular velocity, leading to improved stability regions for the drilling process.
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Patr?cio, Rafael Veloso. "Estudos de controle na perfura??o de po?os de petr?leo em presen?a de Kick de g?s." Universidade Federal Rural do Rio de Janeiro, 2016. https://tede.ufrrj.br/jspui/handle/jspui/1543.
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Funda??o de Apoio a Pesquisa Cient?fica e Tecnol?gica da UFRRJ-FAPUR
Controling of downhole pressure is essential for a safety process of oil well drilling. In a permeable formation, fluids from reservoir come into the annulus region (wellbore) when the downhole pressure is below pore pressure, featuring a disorder called kick. Literature reports some mathematical models developed to predict the behavior of the wellbore in presence of gas kick, however, there are few works reporting control and experiments. By this reason, it was built an experimental plant in order to study system?s behavior during fluid inlet (gas) from reservoir to annulus, and then, sought to develop a control strategy able to mitigate this disorder, without shut-in the well. A strategy with reconfiguration of the control law feedback?feedforward was designed to reject disturbance (gas inlet in the annular), to ensure the drilling within the operating window. Parallelly,simulation studies were developed which are: the construction of mathematical model, validated by the employment of the experimental unit, and the implementation of control based on reconfiguration of control law.
O controle da press?o anular de fundo ? fundamental para que a perfura??o de po?os de petr?leo seja feita de forma segura. Em uma forma??o perme?vel, fluidos do reservat?rio migram para a regi?o anular quando a press?o anular de fundo est? abaixo da press?o de poros, caracterizando o dist?rbio denominado kick. A literatura reporta alguns modelos matem?ticos desenvolvidos para prever o comportamento do po?o na presen?a de kick de g?s, por?m poucos s?o os trabalhos abordando controle e experimentos. A partir desta motiva??o, foi constru?do uma planta experimental para estudar o comportamento do sistema durante a entrada de fluido (g?s) do reservat?rio no anular, e assim, buscou-se desenvolver uma estrat?gia de controle que mitigue tal dist?rbio sem a necessidade do fechamento total do po?o. Uma estrat?gia com reconfigura??o da lei de controle feedback?feedforward foi desenvolvida para rejeitar a perturba??o (entrada de g?s no anular), visando assegurar a perfura??o dentro da janela operacional. Paralelamente, foram desenvolvidos estudos de simula??o quais sejam: a constru??o de um modelo matem?tico, validado empregando-se a unidade experimental, e a implanta??o de controle baseado em reconfigura??o da lei de controle
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De, Lai Fernando César. "Simulação numérica do escoamento particulado para o preenchimento de canal fraturado." Universidade Tecnológica Federal do Paraná, 2013. http://repositorio.utfpr.edu.br/jspui/handle/1/793.
Full textAbstract:
No processo de perfuração, a perda de fluido para o reservatório é um dos principais fenômenos que podem comprometer a produtividade do poço. A eventual presença de fraturas, combinadas aos elevados gradientes de pressão, no conjunto poçoreservatório, intensifica o fenômeno de invasão de fluido. Quando não previsto, este fenômeno deve ser controlado de forma a restabelecer a circulação no poço. Neste trabalho, o controle da invasão de fluido é realizado através do processo de injeção de partículas sólidas para vedação das fraturas. A simulação numérica do problema investigado é dividida em duas partes, diferenciadas pelo tipo de escoamento no canal fraturado: escoamento monofásico de fluido, para a análise do fenômeno de invasão; e escoamento bifásico líquido-sólido, para o processo de preenchimento da fratura com material particulado. A formulação matemática e a modelagem numérica para o escoamento particulado são representadas por uma abordagem Euler-Lagrange. A solução acoplada das fases discreta (partículas) e contínua (fluido) é realizada através da combinação dos modelos Dense Discrete Phase Model (DDPM) e Discrete Element Method (DEM), disponíveis no programa ANSYS FLUENT. O preenchimento das fraturas é caracterizado pela análise do tempo de injeção (no canal) e formato do leito fixo (na fratura) das partículas. Esta caracterização é obtida através da variação dos parâmetros principais de injeção das partículas, que influenciam a concentração de partículas no interior do canal. Resultados mostram o efeito da variação da concentração de sólidos da fase particulada para diferentes parâmetros de monitoramento, sendo os principais a vazão de fluido pela saída da fratura, a pressão da mistura na entrada do canal e a concentração de partículas injetadas no canal.During the drilling process, the fluid loss to formation is one of the most important players that affect the productivity of the well. When combined with high pressure gradients at the wellbore-reservoir interface, fractures may eventually magnify the invasion phenomenon. These phenomena, when not predicted, must be controlled to restore the wellbore circulation. In this work, the fluid invasion is managed by injecting solid particles with the drilling fluid to obturate the fracture. The numerical simulation of the problem here investigated is divided in two parts, concerning the type of flow in the channel: monophase fluid flow, to analyze the invasion phenomenon and twophase flow (fluid and particles), to filling process of the fracture with particulated material. The mathematical formulation and numerical modeling are represented via an Euler-Lagrange approach. Coupled solution of discrete (particles) and continuum (fluid) phases is performed by combining the models Dense Discrete Phase Model (DDPM) and Discrete Element Method (DEM) available in ANSYS FLUENT. The filling of the fractures is characterized by analyzing the injection time (in the channel) and the format of the fixed bed (in the fracture) of the particles. This characterization is obtained by the variation of the main parameters for the particles injection that influence the concentration of particles within the channel. The results show the effect of varying the concentration of the solid particle phase for different monitoring parameters. The main parameters are the fluid flow rate through the outlet of the fracture the pressure of the mixture in the inlet of the channel and the concentration of particles injected into the channel.