Dissertations / Theses on the topic 'Gas wells'
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Al, Mutairi Fahad M. "Evaluation of skin factor from single-rate gas well test." Morgantown, W. Va. : [West Virginia University Libraries], 2008. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=6047.
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Thesis (M.S.)--West Virginia University, 2008.Title from document title page. Document formatted into pages; contains viii, 75 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 38-43).
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Shi, Chunmei. "Flow behavior of gas-condensate wells /." May be available electronically:, 2009. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Liao, Tianlu. "Mechanistic modeling of intermittent gas lift /." Access abstract and link to full text, 1991. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/9210710.
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Adeyeye, Adedeji Ayoola. "Gas condensate damage in hydraulically fractured wells." Texas A&M University, 2003. http://hdl.handle.net/1969.1/213.
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This project is a research into the effect of gas condensate damage in hydraulically fractured wells. It is the result of a problem encountered in producing a low permeability formation from a well in South Texas owned by the El Paso Production Company. The well was producing a gas condensate reservoir and questions were raised about how much drop in flowing bottomhole pressure below dewpoint would be appropriate. Condensate damage in the hydraulic fracture was expected to be of significant effect.
Previous attempts to answer these questions have been from the perspective of a radial model. Condensate builds up in the reservoir as the reservoir pressure drops below the dewpoint pressure. As a result, the gas moving to the wellbore becomes leaner. With respect to the study by El-Banbi and McCain, the gas production rate may stabilize, or possibly increase, after the period of initial decline. This is controlled primarily by the condensate saturation near the wellbore. This current work has a totally different approach. The effects of reservoir depletion are minimized by introduction of an injector well with fluid composition the same as the original reservoir fluid. It also assumes an infinite conductivity hydraulic fracture and uses a linear model.
During the research, gas condensate simulations were performed using a commercial simulator (CMG). The results of this research are a step forward in helping to improve the management of gas condensate reservoirs by understanding the mechanics of liquid build-up. It also provides methodology for quantifying the condensate damage that impairs linear flow of gas into the hydraulic fracture.
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Reza, Rostami Ravari. "Gas condensate damage in hydraulically fractured wells." Texas A&M University, 2004. http://hdl.handle.net/1969.1/1100.
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This project is a research into the effect of gas condensate damage in hydraulically fractured wells. It is the result of a problem encountered in producing a low permeability formation from a well in South Texas owned by the El Paso Production Company. The well was producing from a gas condensate reservoir. Questions were raised about whether flowing bottomhole pressure below dewpoint would be appropriate. Condensate damage in the hydraulic fracture was expected to be of significant effect.
In the most recent work done by Adedeji Ayoola Adeyeye, this subject was studied when the effects of reservoir depletion were minimized by introduction of an injector well with fluid composition the same as the original reservoir fluid. He also used an infinite conductivity hydraulic fracture along with a linear model as an adequate analogy. He concluded that the skin due to liquid build-up is not enough to prevent lower flowing bottomhole pressures from producing more gas.
This current study investigated the condensate damage at the face of the hydraulic fracture in transient and boundary dominated periods when the effects of reservoir depletion are taken into account. As a first step, simulation of liquid flow into the fracture was performed using a 2D 1-phase simulator in order to help us to better understand the results of gas condensate simulation. Then during the research, gas condensate models with various gas compositions were simulated using a commercial simulator (CMG). The results of this research are a step forward in helping to improve the management of gas condensate reservoirs by understanding the mechanics of liquid build-up. It also provides methodology for quantifying the condensate damage that impairs linear flow of gas into the hydraulic fracture.
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Juell, Aleksander. "Production Optimization of Remotely Operated Gas Wells." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for petroleumsteknologi og anvendt geofysikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-15934.
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Foss, Matthew. "Operating costs at the well level for natural gas wells in Alberta." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ64912.pdf.
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Tesfaslasie, Samson. "Automatic type curve matching for predicting gas wells production." Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=916.
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Thesis (M.S.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains xv, 113 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 67-68).
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Kalantari-Dahaghi, Amirmasoud. "Reservoir modeling of New Albany Shale." Morgantown, W. Va. : [West Virginia University Libraries], 2010. http://hdl.handle.net/10450/11022.
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Thesis (M.S.)--West Virginia University, 2010.Title from document title page. Document formatted into pages; contains xii, 81 p. : ill. (some col.), col. maps. Includes abstract. Includes bibliographical references (p. 68-69).
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Yussefabad, Arman G. "A simple and reliable method for gas well deliverability determination." Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5280.
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Thesis (M.S.)--West Virginia University, 2007.Title from document title page. Document formatted into pages; contains xi, 79 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 42-47).
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Eljack, Hassan Daffalla. "Combine gas deliverability equation for reservoir and well." Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5285.
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Thesis (M.S.)--West Virginia University, 2007.Title from document title page. Document formatted into pages; contains viii, 56 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 45-46).
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Ding, Wenzhong. "Analysis of data from a restricted-entry well /." Access abstract and link to full text, 1989. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/9015983.
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Diazgranados, Jonathan. "Gas production forecasting using automatic type curve matching." Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1331.
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Thesis (M.S.)--West Virginia University, 2000.Title from document title page. Document formatted into pages; contains xii, 131 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 81-82).
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Joseph, Amieibibama. "Investigation of liquid loading phenomena in gas wells." Thesis, University of Aberdeen, 2016. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=230529.
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Mahdiyar, Hojjat. "Gas condensate flow around hydraulically fractured/perforated wells." Thesis, Heriot-Watt University, 2009. http://hdl.handle.net/10399/2215.
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Gas condensate flow, which is very different from the conventional two-phase (oil and gas) flow, shows more complicated behaviour around the wellbore owing to condensate buildup and the different velocity effects on relative permeability (kr) of these low IFT fluid systems. This is especially true for complex wellbore completions, such as hydraulically fractured or perforated wells. This research programme has two separate parts. The first part is about gas condensate flow around hydraulically fractured wells (HFWs). In this part of the study, different inhouse simulators have been developed by the author. These simulators account for the changes in fluid properties with pressure, phase change, coupling (increase in kr as IFT decreases or velocity increases) and inertia (decrease in kr when velocity increases) when it is required to do so. The simulators have been used to investigate the effect of different important geometrical and flow parameters on the performance of a HFW. The new developed formulae for accurate estimation of effective fracture conductivity, fracture skin factors (mechanical and flow) and effective wellbore radius are the main practical outcomes of this part of the study. The author has also provided a new convenient method for the optimization of fracture dimensions for a given fracture volume, in gas condensate reservoirs. The second part of this research is about the study of gas condensate flow around perforated wells. Here the previously developed simulators by the Gas Condensate Research group have been used to develop a new method for estimation of mechanical perforation skin. The introduction of a method for calculation of effective wellbore radius of a perforated well by which the flow skin is negligible is another important result of this part. The new formulae introduced in this work can be used as a useful tool for estimation of well productivity/injectivity. They are also very useful in reservoir simulation, because having the effective wellbore radius for a complex wellbore geometry- such as a perforated well or hydraulically fractured well - provides an opportunity to define a simple open-hole system instead of the real wellbore. This eliminates the need for a costly and cumbersome fine grid exercise, which otherwise would be required to capture accurately the variation of flow parameters around these types of wellbores.
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Shmeleva, Mariia. "Geothermal Energy Production from Oil and Gas Wells." Thesis, KTH, Energiteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-245059.
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This Thesis presents an investigation of geothermal energy production and utilization for electricity generation on the petroleum fields. According to the global energy market in Russia, the leading position takes oil and gas industry. Experts say that most of large petroleum deposits are depleted and the water cut reaches up to 80-90%. To develop such fields and deposits is not economic attractive, that is why wells with high water cut, more than 95%, are turned into abandoned wells. The technology of obtaining geothermal energy from abandoned wells allows reusing already drilled deep wells to generate electricity in an environmentally friendly way. It is especially relevant in oilfields isolated from the grids. In this work the scheme of geothermal energy extraction and utilization is presented. Based on the knowledge of heat exchange in a well and foreign experience a mathematical model describing heat exchange between injected fluid and surrounding rocks in a double pipe was developed. Apart from that the main factors affecting the efficiency of geothermal heat extraction and electricity generation were thoroughly examined. Furthermore, the economic and ecological effect from electricity production by ORC was defined.Denna avhandling presenterar en undersökning av produktion av geotermisk energi och utnyttjande av elproduktion på petroleumsområdena. Enligt den globala energimarknaden i Ryssland tar ledande position olje- och gasindustrin. Experter säger att de flesta stora oljefyndigheter är utarmade och vattnets snitt når upp till 80-90%. Att utveckla sådana fält och insättningar är inte ekonomiskt attraktiva, det är därför brunnar med högvattenskärning, mer än 95%, förvandlas till övergivna brunnar. Tekniken för att erhålla geotermisk energi från övergivna brunnar möjliggör återanvändning av redan borrade djupa brunnar för att generera el på ett miljövänligt sätt. Det är särskilt relevant i oljefält isolerade från nätet. I detta arbete presenteras systemet för geotermisk energiutvinning och -utnyttjande. Baserat på kunskapen om värmeväxling i en brunn och utländsk erfarenhet utvecklades en matematisk modell som beskriver värmeväxling mellan injicerad vätska och omgivande stenar i ett dubbelrör. Bortsett från detta undersöktes de viktigaste faktorerna som påverkar effektiviteten av geotermisk utvinning och elproduktion. Vidare definierades den ekonomiska och ekologiska effekten av elproduktion av ORC.
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AZEVEDO, FABRICIO GONCALVES. "STUDY OF RELIEF WELLS TO KILL A BLOWOUT IN A SUBSEA GAS WELL." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2017. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=31827@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROAcidentes com influxo descontrolado de hidrocarbonetos em um poço de petróleo (blowouts) são eventos com baixa probabilidade de ocorrência na indústria, porém têm impactos catastróficos. O evento de Macondo, com uma sonda afretada pela British Petroleum (BP) no Golfo do México (GoM), mostrou que um acidente dessa proporção tem um impacto significativo nas pessoas, no meio ambiente, nos ativos e na imagem da empresa. Portanto, uma resposta rápida e definitiva para o problema se mostra necessária. Dentre as possibilidades de se conter um derramamento de óleo ocasionado por um blowout, a mais efetiva para cessar o vazamento com segurança e abandonar definitivamente o poço em descontrole é o poço de alívio. Trata-se de um poço direcional perfurado a uma determinada distância do poço em blowout, respeitando-se critérios mínimos de segurança, com o objetivo de interceptar este no ponto estabelecido em projeto. Após a interceptação, injeta-se fluido de alta densidade que, quando preenche o poço que estava em blowout, gera uma contra-pressão capaz de cessar o influxo de hidrocarbonetos do reservatório. Quando é feita essa contra-pressão e o poço que estava em blowout estiver estável e sem influxo, injeta-se cimento pelo poço de alívio para que seja tamponado o reservatório e o poço possa ser abandonado de forma definitiva. No presente trabalho o enfoque é no amortecimento do poço em blowout através do poço de alívio e, portanto, parte-se do pressuposto que a detecção e interceptação do poço em influxo foi feita com sucesso no ponto desejado. A detecção, a interceptação e o abandono no poço em blowout não são estudados com detalhes. O trabalho é desenvolvido tomando como base um poço exploratório de gás a ser simulado, trabalhando os requisitos de pressão e vazão que melhor se adequam ao proposto. O objetivo do amortecimento do poço em blowout pelo poço de alívio é cessar o influxo descontrolado de forma eficaz, otimizando os parâmetros de pressão, vazão e volume de fluido às capacidades de sondas e embarcações disponíveis no mercado. Caso não seja possível o amortecimento variando a densidade do fluido injetado e a pressão nas bombas de injeção, parte-se para mudanças na estratégia de amortecimento como, por exemplo, variação no número de poços de alívio a serem perfurados para amortecer o poço em blowout ao mesmo tempo. Não será objetivo do presente trabalho a modificação no projeto do poço com o objetivo de facilitar o amortecimento.
Accidents with uncontrolled influx of hydrocarbons into an oil well (blowouts) are events with a low probability of occurrence in the industry. Although, if they occur, the impact may be catastrophic. The Macondo event, with British Petroleum s rig (BP) in the Gulf of Mexico (GoM), showed that an accident of this proportion has a significant impact on people, environment and an image of the company. Therefore, a quick and definitive response for the problem is necessary. There are several possibilities to contain an oil spill caused by a blowout. However, the most effective way to safely plug and abandon (P and A) the blowout well is the relief well. This technique consists of the construction of a directional well at a certain distance from the blowout well, respecting minimum safety criteria, in order to intercept this at the point established in the project. After the interception, kill mud is pumped at high rates what makes a backpressure capable of killing the blowout well. When this backpressure is enough to kill the blowout well, cement is pumped through the relief well to plug and abandon permanently the well. In the present work, the objective is to kill the blowout well and we consider that detection and interception of the blowout well was successfully been made at the target point. Detection, interception and P and A of the blowout well are not covered in detail. This work is developed based on an exploratory gas well to be simulated, working the pump rate and pump pressure requirements that best fit in the proposed one. The purpose of well killing is to kill the well optimizing the parameters of pressure, flow and volume of fluid considering the rig and vessels available in the market. If well killing is not possible by varying the density of the kill mud and pump pressure it will be tried new strategies like changing the number of relief wells at the same time to be drilled killing the blowout well. It s not a purpose of this study to change the well design.
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Salisbury, Peter Evan. "Compositional multiphase vertical lift performance modelling of oil, gas and retrograde gas-condensate wells." Thesis, Heriot-Watt University, 1987. http://hdl.handle.net/10399/1587.
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Cook, Joshua R. "Development of a program to gather and process data from oil and gas fields." Morgantown, W. Va. : [West Virginia University Libraries], 2004. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3727.
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Thesis (M.S.)--West Virginia University, 2004.Title from document title page. Document formatted into pages; contains ix, 80 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 33-34).
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King, Jeremy Scott. "Acoustical signal during hydraulic fracturing." Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=565.
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Thesis (M.S.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains x, 82 p. : ill. (some col.) Vita. Includes abstract. Includes bibliographical references (p. 42).
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Franquet, Barbara Mariela. "Effect of pressure-dependent permeability on tight gas wells." Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/2253.
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Tight gas reservoirs are those reservoirs where the matrix has a low permeability range (k < 0.1 md). The literature documents laboratory experiments under restressed conditions that show stress dependent rock properties are more significant in tighter rocks. For gas reservoirs, real gas properties are also sensitive to variations of pressure, and the correct description of gas flow must include pressure-dependent gas properties. Under these circumstances the resulting equation for real gas flow is a second order, non-linear, partial differential equation. Non-linearities include pressure-dependence of gas viscosity, gas compressibility, reservoir permeability and reservoir porosity. This paper investigates dynamic permeability change as a function of net overburden stress in tight gas reservoirs. The gas reservoir simulator used for this work included pressure-dependent reservoir permeability. Radial flow cases are analyzed using this simulator. During this study we found that from analysis of production data alone, it is impossible to determine the correct permeability value for tight gas reservoirs with pressure-dependent permeability. For the cases studied, the transient performance was similar for both constant permeability and pressure-dependent permeability. This similarity causes constant permeability and pressure-dependent permeability to be indistinguishable, based on analysis of transient performance data. It was found that the productivity index decreases when pressure-dependent permeability is more significant. Finally, this study verified that the method of Ibrahim et al.28 under estimates original gas in place (OGIP) for tight gas reservoirs with pressure-dependent permeability.
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Binder, Benjamin Julian Tømte. "Production Optimization in a Cluster of Gas-Lift Wells." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for teknisk kybernetikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-19043.
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Subsea petroleum extraction systems may be large and complex, and many decisions affect the production. Maintaining high production levels is not a trivial task. As decisions are made based on available information and experience, better decisions come with better information. Decision support tools may provide essential information to achieve better production levels.In this master thesis, different methods are proposed as decision support tools. The aim is to increase the production from a part of a subsea production system, consisting of a manifold with seven producing wells and two flowlines, given certain system constraints. The methods are based on well models and numerical optimization, and both static and dynamic optimization is considered. The well models are non-linear, and binary decisions are also present. The problems that arise are complex MINLP problems, and are solved by combining ’brute force’, ’Branch & Bound’, and a nonlinear solver. The solution of the problems is implemented in MATLAB, and tested on predefined test scenarios, with no, little or extensive dynamics present. The performance is assessed by simulations, and by calculating the resulting average production.It was found that static optimization to decide the well settings, such as valve openings and flowline routing, has a great potential to increase the oil production from the system. The results when applying a dynamic approach to the system were not conclusive, but the methods proposed showed no indications of any major performance increase, relative to applying only static optimization.
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Serra, Kelsen Valente. "Well testing for solution gas drive reservoirs /." Access abstract and link to full text, 1988. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/8811978.
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Yusuf, Nurudeen. "Modeling well performance in compartmentalized gas reservoirs." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2107.
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Enoh, Michael E. "A tool to predict the production performance of vertical wells in a coalbed methane reservoir." Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5362.
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Thesis (M.S.)--West Virginia University, 2007.Title from document title page. Document formatted into pages; contains vii, 46 p. : ill. (some col.), col. map. Includes abstract. Includes bibliographical references (p. 42-43).
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Amin, Aram. "Well test analysis of infrequent flow behaviour of fractured wells in oil and gas reservoirs." Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/24556.
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The purpose of hydraulic fracturing is to increase the contact area of the wellbore in the reservoir to maximise production rates. For modelling purposes, the induced fracture is assumed to be of infinite or finite conductivity. The modelled fracture tends to show either features of infinite conductivity with half slope or finite conductivity with quarter slope at early time. These flow behaviours are clear indications of a stimulated well. However, observations in some post-frac well tests report a single unit slope in early time, which indicates non-fractured well response. The objective of this study is to investigate the unusual flow behaviour associated with the testing of fractured wells following a proppant frac job and address reasons for this behaviour assuming the frac job has targeted the reservoir interval of interest. This infrequent behaviour is referred to briefly in a limited number of publications but with no clear explanation. Study suggests that the controlling factors are fracture length, fracture conductivity, non-Darcy flow in the case of gas wells and the damage caused by the fracture operation including choked fracture effect and less importantly fracture face skin. This study utilizes 3-D numerical black oil and compositional simulation in single and multi-layered reservoirs containing different fluid types. A range of factors are examined that may impact the introduced fracture flow behaviour based on actual fractured well flow features found in the literature. The main fracture and reservoir parameters investigated include: fracture half-length (xf), fracture conductivity (kfwf), fracture damage including fracture choke (Sfc) and fracture face skin (Sff), non-Darcy effect, formation permeability and many others. The study also examines fractured well behaviour in naturally fractured reservoirs and gas-condensate (lean and rich) reservoirs to investigate liquid drop out effect on the induced fracture flow behaviour. It is concluded that the investigated fracture behaviour is likely to be associated with damaged fractures of short lengths and low fracture conductivity values, which often result from poorly executed frac job on the well. Knowledge obtained from the study is applied to the analysis of well tests from actual fractured wells. Understanding the flow behaviour of fractured wells is crucial to operators and service companies in evaluating the effectiveness of stimulation work performed on the well.
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Camacho-Velázquez, Rodolfo Gabriel. "Well performance under solution gas drive /." Access abstract and link to full text, 1987. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/8720613.
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Nordsveen, Espen T. "Mixed Integer Model Predictive Control of Multiple Shale Gas Wells." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for teknisk kybernetikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18400.
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Horizontal wells with multistage hydraulic fracturing are today the most important drilling technology for shale gas extraction. Considered unprofitable before, the production has now become economically profitable due to advances in technology. Shales main characteristics is its low permeability, making the gas challenging and expensive to extract. Hydraulic fracturing stimulates the wells by creating additional conductivity, making the gas flows from storage pores to the well. This flow only possible in a short time scale, and states the need for multistage fracturing. Shale gas flow therefore exhibits a high initial peak, followed by a rapid decline in production rates. The use of shut-ins of shale gas wells allows for pressure build-up and may prevent liquid loading, as a means of boosting production. Shut-ins are used as on/off control variables in short-term model-based optimization of multiple shale gas wells with the objective of tracking a reference rate, while at the same time avoiding liquid loading. Previous work have focused on open-loop optimization. Here, an open-loop formulation is compared to a closed-loop formulation, in the form of mixed integer model predictive control. Both formulations are implemented in IBM ILOG CPLEX, with and without disturbances. Optimal production settings are solved in the presence of global constraints on production rates and minimal shut-in time. This allows for shut-ins with variable periods. The implementation is sensitive to initial conditions, horizons and weighting factors. The closed-loop formulation shows the best ability to reduce the effects of disturbances.
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Hersandi, Sandi Rizman. "Modeling of Water Behavior in Hydraulically-Fractured Shale Gas Wells." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for petroleumsteknologi og anvendt geofysikk, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-23614.
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This study presents the modeling of water behavior in hydraulically-fractured of shale gas wells. A five layers model represents a hydraulically-fractured shale gas well was built in Sensor reservoir simulator through Pipe-It, integrated asset management software. Stress dependent permeability multiplier is applied in the model to represent the permeability enhancement in the zone close to the fracture face during the fracturing stimulation. An implicit black-oil logarithmic model with a total of grid number of 5,800 and thickness of 200 ft is used as the base case model. The horizontal well extends through the reservoir in x-direction. The fracture is located in the center of x-axis, while the tip of the fracture is in the middle of y-axis.Water behavior in the fracture for this study is represented by water saturation within the fracture grids. A better understanding of water behavior in the fracture and its effects on the production profile was obtained through several sensitivity cases, which include number of layers, perforation location, matrix permeability, gas production rate, and shut-in time.Based on the sensitivity tests, it was observed that high water saturation in the fracture is found when the perforation is located in the uppermost layer of the model. For matrix permeability sensitivity, the total kh for the model is maintained at a constant. Reservoir with high matrix permeability in the uppermost layer gives higher water saturation in the fracture. The varying gas production rates influence the water saturation in the fracture. Higher gas rates result in higher water saturation in the fracture. The water saturation profile analysis based on the rate sensitivity shows that a critical gas rate to feed the water from the matrix to the fracture is expected to exist. Water saturation profiles in the matrix have relatively the same profile according to shut-in sensitivity. These differing water saturation profiles on the shut-in sensitivity indicate delayed of water feed from the matrix to the fracture.Also, different perforation locations affect the water production profile, but not on the gas production profiles. Both gas and water production profiles are not significantly affected by different matrix permeability values. Rate sensitivity shows that higher gas rate results in higher total water production. Shut-In period also affects the production profiles. Gas and water productions are observed to decrease with an increased shut-in time due to the delay of production. It is noteworthy that the differences in total water productions are substantial. This is due to shut-in period after water injection reduces water recovery, as compared to immediate production after water injection.From the sensitivities applied to the model, water saturation in the fracture is generally affected by all sensitivity parameters, thus also affects production profiles. This study contributes to having a better understanding in the water behavior in the fracture and the production profiles of shale well gas.
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Purnomo, Hadi. "Inflow performance relationship for gas condensate and volatile oil wells." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300786.
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Hammond, Christopher D. (Christopher Daniel). "Economic analysis of shale gas wells in the United States." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/83718.
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Thesis (S.B.)--Massachusetts Institute of Technology, Department of Mechanical Engineering, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 65-66).
Natural gas produced from shale formations has increased dramatically in the past decade and has altered the oil and gas industry greatly. The use of horizontal drilling and hydraulic fracturing has enabled the production of a natural gas resource that was previously unrecoverable. Estimates of the size of the resource indicate that shale gas has the potential to supply decades of domestically produced natural gas. Yet there are challenges surrounding the production of shale gas that have not yet been solved. The economic viability of the shale gas resources has recently come into question. This study uses a discounted cash flow economic model to evaluate the breakeven price of natural gas wells drilled in 7 major U.S. shale formations from 2005 to 2012. The breakeven price is the wellhead gas price that produces a 10% internal rate of return. The results of the economic analysis break down the breakeven gas price by year and shale play, along with P20 and P80 gas prices to illustrate the variability present. Derived vintage supply curves illustrate the volume of natural gas that was produced economically for a range of breakeven prices. Historic Natural Gas Futures Prices are used as a metric to determine the volumes and percentage of total yearly production that was produced at or below the Futures Price of each vintage year. From 2005 to 2008, the total production of shale gas resulted in a net profit for operators. A drop in price in 2009 resulted in a net loss for producers from 2009 to 2012. In 2012, only 26.5% of the total gas volume produced was produced at or below the 2012 Natural Gas Futures Price.
by Christopher D. Hammond.
S.B.
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Ghahri, Panteha. "Modelling of Gas-condensate flow around horizontal and deviated wells and cleanup efficiency of hydraulically fractured wells." Thesis, Heriot-Watt University, 2010. http://hdl.handle.net/10399/2354.
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Gas condensate reservoirs, when the pressure falls below dew point, are characterised by the appearance of condensate bank and exhibiting a complex phase and flow behaviour around the wellbore. The unique dependency of the gas and condensate relative permeability (kr) on the velocity and interfacial tension (IFT) complicates the well productivity calculations both in field simulation models and in simple engineering calculations, especially for complex well geometries such as horizontal or deviated or hydraulically fractured wells. The current research work has two parts. The first part is devoted to study the flow behaviour around horizontal wells (HWs) and deviated wells (DWs) in gas condensate reservoirs. Here, several in-house simulators have been developed for single-phase and two-phase gas condensate flows. The two phase in-house simulators accounts for the phase change and the dependency of relative permeability to interfacial tension and velocity, due to coupling (increase in kr by an increase in velocity or decrease in IFT) and inertia (a decrease in kr by an increase in velocity). The integrity of the in-house simulators has been verified by comparing some of its results with those obtained using the fine grid option of the ECLIPSE300 commercial reservoir simulator under the same flow conditions. Using the 3-D in-house simulator a large data bank has been generated covering a wide range of variations of pertinent geometrical and flow parameters. Then a general approach is proposed for estimation of an effective wellbore radius of an equivalent open-hole (EOH) radial 1-D system replicating flow around the 3-D HW system. The results of the proposed formulation, which benefits from suitable dimensionless numbers, has been tested against the simulator results not used in its development confirming the integrity of the approach. The proposed formulation, which is simple and easy to use, correctly converts to that suitable for single-phase non-Darcy (inertial) flow systems when total gas fractional flow (GTR) is unity. An extensive sensitivity study has also been conduct to highlight the limitations of current geometric skin formulations widely used in the petroleum industry for HW productivity calculations. The in-house improved geometric skin formulation is more efficient especially for anisotropy, partial penetration and location of HW in the vertical direction. The same exercises have been performed to study the flow behaviour around deviated wells. That is, the corresponding proposed mechanical and flow skin factors ii i are converted into an effective wellbore radius, before being applied in the pseudo-pressure calculation of the equivalent open hole system. Here due to the similarity of flow around HWs and DWs a simple relationship is proposed between the corresponding skin factors of these two well geometries. Therefore, in the proposed general method for modelling of the two-phase flow of gas and condensate around a DW, effective wellbore radius estimated for the HW with the same well length is converted to skin and then included in the proposed formulation before being converted to the effective wellbore radius of the equivalent open hole model replicating flow around 3-D flow geometry. Hydraulic fracturing is one of the most important stimulation techniques especially for tight gas reservoirs. The second part of this research work is devoted to conduct a parametric study to evaluate the impact of the pertinent parameters on the cleanup efficiency, as one of main reasons for poor performance of hydraulic fracturing operation, of gas and gas condensate reservoirs. This study has two parts. In the first part, a comprehensive sensitivity study conducted to evaluate the impact of pertinent parameters on the cleanup efficiency of a hydraulically (gas or gas-condensate) fractured well. Here the key parameters which have significant impact on the gas production loss (GPL) are identified. A new method is proposed to simulate a more realistic fracture fluid (FF) invasion into matrix and fracture, which proves to be one of the main reasons of the contradictory results found in the literature. However since none of such studies have embarked on a much needed extensive investigation of variation of all pertinent parameters, the second part of study is concentrated on a much more expanded study following statistical approaches. Here based on the results of the first part, key parameters have been identified. A 2-level full factorial statistical experimental design method has been used to sample a reasonably wide range of variation of pertinent parameters covering many practical cases for a total of 16 parameters. Since over 130000 simulation runs have been required, to cover the range of variation of all parameters the simulation process has been simplified and a computer code, which automatically links different stages of these simulations, has been developed. The analysis of the simulation runs using two response surface models (with and without interaction parameters) demonstrates the relative importance of the pertinent parameters after different periods.
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Botner, Elizabeth. "Elevated methane levels from biogenic coalbed gas in Ohio drinking water wells near shale gas extraction." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1439295392.
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Binli, Ozmen. "Overview Of Solutions To Prevent Liquid Loading Problems In Gas Wells." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12611560/index.pdf.
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Every gas well ceases producing as reservoir pressure depletes. The usual liquid presence in
the reservoir can cause further problems by accumulating in the wellbore and reducing
production even more. There are a number of options in well completion to prevent liquid
loading even before it becomes a problem. Tubing size and perforation interval
optimization are the two most common methods. Although completion optimization will
prevent liquid accumulation in the wellbore for a certain time, eventually as the reservoir
pressure decreases more, the well will start loading. As liquid loading occurs it is crucial to
recognize the problem at early stages and select a suitable prevention method. There are
various methods to prevent liquid loading such asgas lift, plunger lift, pumping and velocity string installation. This study set out to construct a decision tree for a possible expert system used to determine the best result for a particular gas well. The findings are tested to confirm by field applications as attempts of the expert system.
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Ross, Robert Ian Laird. "Drilling sour gas wells : risk management alternatives for northeast Calgary, Alberta." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26602.
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There is a growing public awareness of and opposition to the risks associated with the operation of hazardous industrial facilities near populated areas. Public concern escalates when the industrial activity possesses the potential for catastrophic consequences should a major accident occur. This study examines the risk of drilling a toxic, natural sour gas well near northeast Calgary, Alberta. The sour gas problem is indicative of the difficulties of finding socially acceptable solutions to such risky activities.
The sour gas industry in Alberta has been successfully drilling for sour gas reserves for over sixty years. Although there has never been a public death in the province as a direct result of exposure to the lethal hydrogen sulphide component of sour gas, recent uncontrolled accidental releases, or 'blowouts,' at sour gas wells have caused the public in Alberta to view the risks of drilling for the toxic reserves near residential communities too big to take. Because of the complexity and enormous array of uncertainties in predicting the likelihood and severity of a sour gas well blowout, the Energy Resources Conservation Board as the regulator and manager of Alberta's oil and gas industry is confronted with widely divergent opinions of the danger of drilling sour gas wells. A risk management interpretation of the sour gas problem assumes a holistic approach, and utilizes knowledge—in depth, case specific information to help understand the uncertainties, the difficulties and implications of successfully drilling sour gas wells near urban centres. Personal work experience by this author on sour gas well drilling rigs enhances the validity and creditability of the risk management approach to sour gas. The main objective of this study, therefore, is to suggest alternatives to the manner sour gas wells are currently examined, regulated, drilled and managed in Alberta.
The thesis recognizes however, that in certain sour gas applications because potential consequences of an accident are extreme, that the risk cannot be effectively managed. In such instances, the proposal may have to be denied.
The risk management study begins by examining how the land use conflict between urban development and sour gas development materialized.
By understanding the uncertainties of safely drilling sour gas wells, especially with regard to the vital role that human error can play in contributing to a well control problem, the inadequacy of a technical solution to risky problems is emphasized.
Upon an extensive review of the literature relevant to risk research, the limitations of a quantitative, probabilistic approach to understand risky activities like drilling sour gas wells is outlined.
Crucial to the risk management process is the need to recognize the legitimacy of the public's perceptions, concerns and fears of risks and to more readily include the public in discussions of the risks. Unless the public's point of view is understood, the principal difficulty of managing risky disputes, reconciling different opinions of the risks, will remain very prominent.
The sour gas industry in Alberta is at a critical point of development. The current sour gas proposal possesses the potential to represent the precedent for the manner the risks of sour gas will be managed.
The examination of this problem presents an opportunity to learn about the technical, moral, economic, social and psychological implications of operating hazardous industrial activities near residential communities. Unfortunately, this thesis has concluded that those involved in the sour gas problem have a great deal of catching up to do to assume a place in the classroom of understanding a holistic interpretation of the risks of sour gas.Applied Science, Faculty of
Community and Regional Planning (SCARP), School of
Graduate
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El, Kamkhi M. "Investigation into descaling of production tubing in oil and gas wells." Thesis, University of Salford, 2011. http://usir.salford.ac.uk/26650/.
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One of the most common production problems in oil and gas fields is scale deposition within oil and gas wellbores. Scale formation in surface and subsurface oil and gas production equipment has been recognised to be a major operational problem. The effect of scale formation is a reduction in the well productivity and the damage to safety valves and gas-lift mandrels. This investigation proposes a new and novel technique to address the problem and lay the foundations for a methodology for descaling in-situ production tubing. This problem currently requires either aggressive chemicals or extraction and replacement tubing both of which are very expensive. The overall aim of this investigation is to study the fundamentals of the decaling process using flat fan sprays at high water pressure ( < 6 MPa ) and high impact force (< 0.657MPa). The spray was characterised quantitatively and qualitatively under ambient conditions utilising single flat fan atomiser or a combination of two or three atomisers with an overlapping configurations. The volume (or mass) flux (VLf) was measured using a patternator which was designed during this investigation. Liquid volume (or mass) flux was found to be symmetrical at different downstream distances (25, 50 and 75 mm). Impact force (IF) was also experimentally measured at different downstream distances (25, 50 and 75 mm) and at various water supply pressure of 3.7, 4.8 and 6 MPa for the corresponding sprays. The result showed that impact force can lie between 0.146 to 0.657MPa Sprays were also characterised using Phase-Doppler Anemometry (PDA). The range of velocity (U) was found to be between 62.48 to 81.85 m/s at 25 mm downstream distance whilst at 50 mm downstream, it was in the range of 55.96 to 73.13 m/s and at 75 mm was between 48.89 to 66.98 m/s. However, the Sauter mean drop size diameter (D^ at 25 downstream distances was found to be in the range of 62.45 um to 75.80 urn and at 50 mm downstream the drop size was between 67.30 jam to 81.43 urn whereas at 75 mm it was 73.56um to 86.42 um. Also, from the results, the liquid volume flux (ULf) obtained using PDA was measured to be between 0.063 and 1.2 (cm3/s)/cm2 at 25 mm downstream and 0.016 to 0.250 (cm3/s)/cm2 at 50 mm and 0.010 to 0.120 (cm3/s)/cm2 at 75 mm downstream distance. Comparing these results with those found via patternator mesurements showed in some instanous, that there is significant (i.e up to 90%) difference between each values which were obtained by the PDA, measured at the centre of the sprays. This was mainley to lack of caputuring the certain drop sizes by PDA and also the design geometry of the patternator together with the nature of flat shape of the spray being not truly flat. Simulated laboratory scale removal rig was subsequently designed and built to demonstrate the effects of using overlapping flat sprays atomisers to remove scales that normally found in oil and gas. Four scale samples (candle wax, soft oil wax, soft gas and oil hard) were tested. The quantity of scale removed using soft candle wax was (53 cm3) at 30 degree atomiser angle to the vertical axis. The scales samples which were obtained from both oil and gas fields were also tested as follows: - a total of 11.688 cm3 of soft scale was removed using three high pressure and high impact atomisers whilst the volume of the scale removed from the oil wax was within 13.750 cm3 for the hard oil scale was found to be approximately 0.989 cm3 . The structures of the flat sprays were also mathematically analysed using the Computational Fluid Dynamics (CFD) package which allowed validating the PDA data. The velocity of the drops compared well with those obtained from PDA. The liquid volume flux, however, was found, generally, between 26% < ULf < 90% compared with those of PDA data.
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Khajotia, Burzin. "Cased based reasoning Taylor series model to predict corrosion rate in oil and gas wells and pipelines /." Ohio : Ohio University, 2007. http://www.ohiolink.edu/etd/view.cgi?ohiou1173828758.
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Bahrami, Hassan. "Evaluating factors controlling damage and productivity in tight gas reservoirs." Thesis, Curtin University, 2012. http://hdl.handle.net/20.500.11937/1559.
Full textAbstract:
Production at economical rates from tight gas reservoirs in general is very challenging not only due to the very low intrinsic permeability but also as a consequence of several different forms of formation damage that can occur during drilling, completion, stimulation, and production operations. The common strategies used in tight gas reservoirs development are hydraulic fracturing and horizontal well drilling. However in many cases of tight gas reservoirs, the key factors that control well productivity and formation damage mechanisms are not well understood, since it is challenging to characterise them in tight formations.In this thesis I demonstrate how different well and reservoir parameters control well productivity and damage mechanisms in tight gas reservoirs. Reservoir simulation model for Whicher Range tight gas field is built and run. Analytical and numerical simulation approaches are integrated with core flooding experiments and tight gas field data analysis in order to characterize the key reservoir parameters and understand the effects of different parameters on well productivity.Using core flooding experiments data analysis, the relative permeability curves are generated for Whicher Range tight gas reservoir, and quantitatively is shown how the phase trapping damage can be reduced by use of oil based drilling fluid instead of water based fluid. A new technique of welltest analysis was introduced for tight gas reservoirs that can reduce uncertainties in estimation of average reservoir permeability, and also a new correlation that can determine permeability of the natural fractures in tight formations is proposed in this study. I study and analyse different well completion, production and reservoir data from Whicher Range tight gas field in order to identify why production rates are significantly lower than expectations, and investigate possible remedial strategies to achieve viable gas production rates.Based on this research, drilling long horizontal deviated wells using non-aqueous fluids in underbalanced conditions may be more efficient than hydraulic fracturing. As the optimum strategy to further improve the well productivity, drilling the well with a high deviation to intersect multiple sand lenses; orienting the wellbore direction perpendicular to the maximum horizontal stress to intersect higher permeability conduits and control wellbore instability issues; completing the well as open-hole to have the advantage of enlarged wellbore caused by large wellbore breakouts; running slotted liner to control wellbore collapse; open-hole perforation in the direction of maximum horizontal stress to reach a deeper formation penetration; and unloading the wellbore from drilling and fracturing fluids can help achieve commercial gas production rates from tight gas reservoirs.
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Vo, Dyung Tien. "Well test analysis for gas condensate reservoirs /." Access abstract and link to full text, 1989. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/9014121.
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Sandrowicz, Daniel Richard. "Gas wells and their impact on archaeological sites in Bradford County, Pennsylvania." Thesis, Indiana University of Pennsylvania, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1569877.
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This study involves creating archaeological predictive models (APMs) for Bradford County, Pennsylvania: a known site model, a regression analysis model, and a multi-criteria analysis model. The APMs show the areas of highest sensitivity for archaeological sites but utilize different methods so that the models can be compared. The thesis also compares locations of known archaeological sites and the areas of high archaeological probability to natural gas well sites to determine the impact of natural gas drilling on the archaeological record. Finally, the thesis addresses whether new archaeological sites can be located using different types of remote sensing. The goal of this study is to provide a planning strategy for the protection of cultural resources. The Commonwealth of Pennsylvania statewide historic plan for 2012-2017 calls for the creation of a statewide archaeological probability map. This study provides a baseline for the future creation of predictive models for the state of Pennsylvania.
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Zhang, Xutuan. "Quantitative risk assessment in drill casing design for oil and gas wells." Thesis, University of Wolverhampton, 2004. http://hdl.handle.net/2436/89102.
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Mu, Langfeng. "A Comparison of Thermal Models for Temperature Profile in Gas-lift Wells." Thesis, University of Louisiana at Lafayette, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10163351.
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A new mechanistic model is developed for computing flowing fluid temperature profiles in both conduits simultaneously for a continuous-flow gas-lift operation. The model assumes steady heat flow in the formation, as well as steady heat flow in the conduits. This work also presents a simplified algebraic solution to the analytic model, affording easy implementation in any existing program. An accurate fluid temperature computation should allow improved gas-lift design.
Comparisons of the Hasan model, Alves model, and the new model with data from the Thompson Well, O’Connor Well, and Luo Wei Well show that the temperature profile given by the new model has a better accuracy than that of other models.
A sensitivity analysis was conducted with the new model. The results indicate that mass flow rate of oil and the tubing overall heat transfer coefficient are the main factors that influence the temperature distribution inside the tubing and that the mass flow rate of oil is the main factor affecting temperature distribution in the annulus. The annulus overall heat transfer coefficient and tubing overall heat transfer coefficient are the next significant factors.
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Cox, Stephen Easton. "The use of horizontal wells for leachate and gas control in landfills." Thesis, University of Southampton, 2002. https://eprints.soton.ac.uk/393610/.
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Barbosa, Luis Felipe Ferreira Motta. "Drilling optimization of petroleum and natural gas wells : application of artificial intelligence /." Guaratinguetá, 2019. http://hdl.handle.net/11449/180784.
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Orientador: João Andrade de Carvalho JuniorCoorientador: Andreas Nascimento
Banca: Mauro Hugo Mathias
Banca: José Luiz Gonçalves
Abstract: To meet the increasing primary energy demand, more challenging petroleum reserves started being explored, such as the reservoirs from pre-salt formation close to the Brazilian and Angolan coasts. Historically, low penetration rates in drilling the pre-salt carbonates were reported in the literature, resulting in large capital expenditure on well's construction. Since the major part of exploration cost is associated with drilling, optimizing this activity is of major importance. In this context, the main objective of the present thesis is to investigate methods for real-time drilling optimization of oil and natural gas wells. A common way to optimize drilling activities is to determine the optimum operational variables (e.g. weight-on-bit and rotational speed) that maximizes the ROP. However, this may yield a decrease in drilling efficiency. An alternative to reduce problems related to drilling inefficiency, such as excessive bit wear and vibrations, is through the selection of operational variables able to minimize the specific energy (SE) spent to excavate a volumetric unit of rock. For that, it is necessary to employ accurate predictive models able to capture how the operational variables (weight-on-bit, rotational speed, mud flow and so on) influence not only on ROP but also on SE. Therefore, the present thesis employed a well-known machine learning method, called random forest, instead of analytical equations found in drilling engineering books. Thus, it was possible to o... (Complete abstract click electronic access below)
Resumo: Para atender à crescente demanda de energia primária, começaram a ser exploradas reservas de petróleo em áreas mais desafiadoras, tais como os reservatórios da formação do pré-sal próximos às costas brasileira e angolana. Historicamente, observa-se baixa taxa de penetração na perfuração dos carbonatos do pré-sal, resultando em altos custos na construção de poços. Como a maior parte dos custos de exploração está associado com perfuração, a otimização desta atividade é de grande importância. Neste contexto, o principal objetivo desta dissertação é investigar métodos de otimização em tempo-real de poços de petróleo e gás natural. Uma forma comum de se otimizar a perfuração é através da determinação dos parâmetros operacionais (peso na broca e rotação) que maximizem a taxa de penetração (rate of penetration, ROP). Contudo, isto pode acarretar na diminuição da eficiência do processo de perfuração. Assim, uma forma de diminuir problemas relacionadas a ineficiências da perfuração, tais como gasto excessivo da broca ou vibrações, é através da seleção dos parâmetros operacionais, minimizando a energia específica (specific energy, SE) gasta para escavar uma unidade volumétrica de rocha. Para tanto, é necessário o emprego de modelos precisos que relacionem como as variáveis operacionais (peso da broca, rotação, vazão do fluido de perfuração entre outros) influenciam, não somente o ROP, mas também a SE. Desde modo, a presente dissertação empregou um método conhecido de aprendizagem de má... (Resumo completo, clicar acesso eletrônico abaixo)
Mestre
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Kanu, Elizabeth. "Expansion driven Unstable Two Phase Flows in Long Risers and Wells." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-14420.
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Flow instabilities in long wells and risers under certain flow conditions, is well known. Expansion driven flow instability (EDI) which is relatively little known, refers to occurrence of flow instabilities in long wells and risers as a result of entrapment of gas upstream of the well or riser base. EDI can also occur in gas-lift systems at low pressure and low gas injection rate.This work was initiated to tackle flow instability problem related to deep water production operations where long wells and risers are extensively in use. The aim of this thesis is to investigate a type of flow instability known as “Expansion Driven Flow Instability (EDI) in Long Wells and Risers”. This involves experimental investigation as well numerical modelling of expansion driven flow instability in long wells and risers. Finally results of the experimental investigations are compared with numerical model data.An experimental flow loop was setup to verify EDI at varying pipe geometry, inlet flow pressure and gas flow rate to examine the effect of EDI in long wells and risers. The laboratory experiment was conducted using air and water at atmospheric conditions, in a flowline-riser system consisting of a 32mm diameter and 9.12m long riser. The expansion driven flow cycle was captured in video recording.Variation of inlet flow pressures was achieved by varying the height of the overflow tank. Three cases were considered, each at a different inlet pressure. Each inlet pressure of the fluid was examined against varying inclination angles of the horizontal pipe to the riser inlet. Different gas flow rates were tested at different inclination angles. It was observed that inclination angle has the greatest impact on EDI.Experimental result of one of the cases was modelled using OLGA and the results of the experimental compared against simulation results output. Discrepancies in the two sets of results were observed in some cases. These may be attributed to simplifications and assumptions made during the simulation model build.Both results of the experimental investigation and numerical simulation demonstrated that expansion driven flow instability can occur in laboratory setup and can probably occur in deep water natural-lift wells and risers as well as gas-lifted wells and risers under certain flow conditions and pipe inclinations. 
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Hatzignatiou, Dimitrios Georgios. "Advances in well testing for solution-gas-drive reservoirs /." Access abstract and link to full text, 1990. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/9033497.
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Fahimpour, Jalal. "Wettability alteration of carbonate rocks to alleviate condensate blockage around gas-condensate wells." Thesis, Heriot-Watt University, 2015. http://hdl.handle.net/10399/2926.
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Yang, Min. "Controlling methane emissions from heavy oil wells, gas clustering simulation and optimization modeling." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0020/MQ49694.pdf.
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Tveit, Hans Erik. "Evaluation of Bentonite as an Alternative Sealing Material in Oil and Gas Wells." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for petroleumsteknologi og anvendt geofysikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-21074.
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A growing number of wells will have to be plugged and abandoned in the future. On the Norwegian continental shelf, 2000 wells will have to be abandoned from 2011-2040. The costs of plugging a well are high and can contribute with up to 25% of the total cost of the well. In this thesis bentonite was evaluated as an alternative sealing material to cement for plug and abandonment of wells. Bentonite shows superior sealing ability due to the fact that it will swell and expand during hydration compared to cement which has the tendency to shrink. A hydrated bentonite plug also has a lower permeability than cement, and it has the ability to reshape itself and heal any cracks which may occur during subsurface movements. A literature study was performed to review previous work, and tests using bentonite as a sealing material was conducted in the lab. In the lab experiments, 9 fullbore plugs and 6 annulus plugs of different lengths made of bentonite pellets were tested. In addition, 7 fullbore plugs and 5 annulus plugs made of dry powdered bentonite were tested. Fullbore plugs were tested in an 8,97cm ID plastic pipe while annulus plugs were tested between the same plastic pipe and a 5,00cm OD plastic pipe. The total length of the test pipe was 1m. In all the experiments, bentonite created a hydraulically solid plug, both for fullbore plugs and annulus plugs. The pressure needed to dislodge the plugs varied from 20kPa to 101kPa with plug lengths from 23cm to 91cm. The pressure was found to increase linearly with the length of the plug for both fullbore plugs and annulus plugs, whether bentonite pellets or dry powdered bentonite were used to create the plugs. This leads to the shear strength τ being independent of plug length. The shear strength τ between the hydrated plugs made of bentonite pellets and the plastic pipes was found to be 1,33 kPa for fullbore plugs and 1,02 kPa for annulus plugs. For plugs prepared by powdered bentonite the shear strength was found to be 1,40 kPa for fullbore plugs and 0,89 kPa for annulus plugs. The density of the hydrated bentonite pellets plugs was found to be 1,533 g/cm3. The expansion from dry volume of pellets to hydrated plug volume was in the range of 92%-120%. The dry density of the pellets before hydration was measured to 2,025 g/cm3. The density of plugs made of powdered bentonite was found to be 1,102 g/cm3. The expansion from dry volume of powdered bentonite to hydrated plug volume was in the range of 283-332%. The dry density of the powdered bentonite was measured to 1,09 g/cm3. Theory and experiments from soil plugs in driven piles predict that a relatively short sand plug can resist very large forces. By placing a suitable sand plug on top of a bentonite plug, the result could be a short total plug length which is impermeable due to bentonite and can resist large forces due to the sand plug. Plug height needed to achieve a plug capacity of 200 bar in a 5 ½” casing is 352m for bentonite pellets using the shear strength found for plastic pipes. By taking the increased roughness of a steel pipe into account the height needed is estimated to 89m. The same pressure rating can be achieved using a combination of a 2m long sand plug placed on top of a 10m long bentonite plug. Further work is suggested to be carried out on combining a bentonite plug with a sand plug located on top. Improved methods for placement of bentonite and sand in the wellbore should also be investigated.
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Hashemi, Abdolnabi. "Evaluation of horizontal gas-condensate wells using pressure transient analysis and compositional simulation." Thesis, Imperial College London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428007.
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