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1
SILVEIRA, BRUNA TEIXEIRA. "3D PORE PRESSURE ESTIMATION". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2009. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=31857@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
PROGRAMA DE EXCELENCIA ACADEMICA
Nos projetos de engenharia de poço, o conhecimento das pressões é fundamental para o planejamento do poço e otimização do processo construtivo. Em geral, as estimativas de pressão de poros são feitas baseadas em análises unidimensionais de poços de correlação e dependem da experiência do analista responsável. Tais estimativas não contemplam todos os dados de uma região e muitas vezes dados não são bem aproveitados. Neste trabalho, é apresentada uma metodologia para estimativa de pressão de poros tridimensional, onde as propriedades dos poços da mesma região foram extrapoladas para toda área através da ferramenta geoestatística. A partir desta extrapolação, foi possível obter-se perfis sintéticos em qualquer locação dentro da região delimitada com maior confiabilidade, enriquecer a compreensão global da região modelada e finalmente construir um cubo tridimensional de pressão de poros utilizando os modelos de Eaton e Bowers, baseando-se no critério que a região apresenta a mesma tendência de compactação.
The knowledge of pore pressures of rocks is critical to several aspects of petroleum the well design and planning. Usually, in the petroleum industry, estimations are based on 1D analyses of the analogues wells and depend on the professional experience. Moreover, estimations do not consider the whole base data of the field. In this dissertation, is presented a methodology for 3D pore pressure estimation, where well data is calculated for the whole area applying a geostatistical tool to build the 3D properties model. From that, it was possible to make more credible synthetics well logs at any location, enrich the whole area comprehension, and also, to build the pore pressure cube based on Eaton and Bowers pore pressure estimations models.
2
Accary, Abdallah. "Experimental characterization of the interstitial pore pressure of wet concrete under high confining pressure". Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI040/document.
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L'objectif principal de cette thèse est d'identifier expérimentalement la pression interstitielle d'un béton très humide sous haute pression de confinement. Ce travail fait partie d'un projet plus général visant à comprendre le comportement des structures en béton soumises à un impact au cours duquel, un état de contraintes triaxiales élevées se produit au sein du matériau. Ces structures en béton, souvent massives, gardent un taux de saturation assez élevé durant leur durée de vie. La quantité d'eau libre dans les pores du béton a un rôle prépondérant sur son comportement sous confinement élevé par rapport à d'autres paramètres du matériau (par exemple: rapport eau / ciment ou porosité du béton). Sous une telle charge, la fermeture de la porosité se produit et provoque une augmentation de la pression interstitielle qui n'a été jamais mesurée.Une nouvelle technique de mesure de pression interstitielle en utilisant la presse triaxiale Giga est proposée dans la première partie de cette étude. Elle consiste à remplacer l'échantillon de béton (14 cm en longueur) par un autre plus petit (8 cm de longueur) et une enclume de collecte d'eau (6 cm de longueur) placé en dessous. Cette enclume est composée de deux parties: un bouchon mobile équipé d'un joint d'étanchéité torique permettant l'accès à l'espace libre de la cellule et d’une cellule équipée des micro-trous en contact avec l'échantillon de béton. Deux types de capteurs de pression ont été développés durant cette thèse, un capteur type Hydrostatique et un de type Membrane. Chacun des deux capteurs de pression est placé dans l'espace libre de l’enclume avant chaque essai. Lorsque l'échantillon est sous compression triaxial à fort confinement, l’eau libre de l’échantillon est drainée dans la cavité par le biais des micro- trous. La conception de chaque capteur, la protection de l’ensemble et les essais d'étalonnage des capteurs de pression sont discutés. La deuxième partie de cette thèse est dédiée aux analyses des résultats de mesure de la pression interstitielle effectuées sur des échantillons de béton de référence (R30A7). Les résultats révèlent que la pression interstitielle peut atteindre une valeur comprise entre 200 et 400 MPa sous une pression de confinement égale à 500 MPa. Une modélisation analytique, dans le cadre poro-mécanique, est développée afin d'estimer la pression interstitielle et le comportement volumétrique du béton sous confinement élevé. La comparaison des résultats de mesure et de modélisation est satisfaisanteThe main objective of this PhD thesis is to identify experimentally the interstitial pore pressure of a very wet concrete under high confining pressure. This work is a part of a more general project aiming to understand the concrete behavior under impact during which, a high triaxial stress states occurs. Besides, massive concrete structures keep a saturation ratio strongly depth dependent almost their life time. The quantity of free water contained in concrete pores has a preponderant role on its behavior under high confinement compare to other material parameters (e.g: water/cement ratio or the concrete porosity). Under such loading, porosity closure occurs and causes an increase of interstitial pore pressure which is never measured.In order to perform interstitial pore pressure measurement, two configurations issued from a new testing technic have been developed using the Giga press of 3SR Lab. The technic, detailed in the first two chapters, consists in replacing the 14 cm R30A7 reference concrete sample by a smaller one with a water collect cap below it. The latter is composed of two parts: a movable plug equipped by a sealing joint permitting the access into the cap free space, and a micro-holed cap which is accosted on the concrete sample. A deformable sensor is placed into the free space of the water collect cap. Thus, when the sample is pressurized at high confinement, the interstitial water inside the concrete is transmitted to the sensor through cap micro-holes. The design, protection and calibration of each sensor are discussed.The second part of this thesis is dedicated for pore pressure analysis results. This latter seems to reach high values ranging from 250 till 400 MPa for 500 MPa of confinement. The concrete volumetric behavior under drained condition is lower than the saturated concrete under undrained condition. The collected data reveals that pore pressure increases linearly with the confining pressure within a slope of 0.7.An analytical modeling, within the poro-mechanical framework, is developed in order to estimate the pore pressure and concrete volumetric behavior under high confinement. The model shows promising results while comparing it to the experimental values
3
Brehaut, Richard Jeremy. "Groundwater, Pore Pressure and Wall Slope Stability – a model for quantifying pore pressures in current and future mines". Thesis, University of Canterbury. Geological Sciences, 2009. http://hdl.handle.net/10092/4465.
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The Hamersley Province, located approximately 1200 km north of Perth, Western Australia forms part of the southern Pilbara craton, an extensive area of Band Iron Formations (BIF). The area has a high economic significance due to several enrichment stages of the country rock (BIF) resulting in several large high-grade iron ore deposits. Mount Whaleback near Newman and Mount Tom Price are the largest deposits, where reserves have been estimated at 1400 Mt and 900 Mt respectively. These ore bodies have been quantified as being high grade resources at approximately 64 % iron, with a high lump to fines ratio, and low impurities. The Mount Tom Price ore body is a hematite-rich ore, associated with a variety of shale and some dolomitic units (MacLeod et al., 1963, MacLeod, 1966, Taylor et al., 2001, Morris, 1980).
The local hydrogeology of the Mount Tom Price area involves two main aquifer systems. The Dales Gorge member of the Brockman Iron Formation with contributions from the upper mineralised section of Footwall zone make up the main semi confined aquifer within the area. The underlying low permeability Mount McRae Shale and Mount Sylvia Shale lithologies separate a secondary aquifer which is located within the Wittenoom Formation. A dewatering program within Mount Tom Price has been ongoing since installation in 1994.
Within the open pit mining industry, pits depths are increasingly being deepened as the easily accessible surface ore has been removed. This involves excavating pit walls below the existing groundwater table, which can lead to instabilities within pit walls. Added to this is the timing and economic considerations which need to be accounted for in a working mine. As dewatering and depressurisation are pivotal to the extraction of ore resources below the groundwater table, there can often be considerable time pressures to maintain planned mine developments (Hall, 2003).
The South East Prongs pit, located within the Mount Tom Price mine, holds some of the most valued low impurity, high grade hematite ore. Structurally the South East Prongs is unique as the deposit lies in the base of a steeply dipping double plunging syncline, intersected by the Southern Batter Fault which runs parallel in strike to the Turner Syncline.
The current pit floor of South East Prongs is located at 600 mRL. The long term development plan for the western end of this pit includes a further 30 m of excavation to a final depth of 570 mRL. This currently poses a number of stability issues that require resolution before any development can be undertaken.
A conceptual understanding of flow dynamics within structurally complex wall rock environment has been generated through the utilisation of finite element numerical modelling. The complex structural setting within the northern wall of the South East Prongs has shown to interact with high conductivity lithologies to promote preferential flow of groundwater from the underling Wittenoom Formation aquifer. Recharge to the semi confined DG aquifer occurs as groundwater travels up shear zones within the South East Prongs Fault Zone before migrating along Brunos Band.
An investigation into alternative methods of depressurisation has been recommended to ensure the ongoing management of pore water pressures within the northern pit wall during planned pit cut backs. Limiting recharge from the WF to the pit through stated preferential flow paths has been identified as a potential issue when the remaining DG aquifer is removed. Maintaining the proposed dewatering buffer will be difficult to achieve using the current system.
The ability to design optimal pit shells for access and ore recovery as well as an effective dewatering and depressurisation system relies heavily on the a sound geological model. Further to this, time allocations to ensure forward planning deadlines are met can be significantly interrupted if adjustments to initial plans are required.
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CRUZ, NOELIA VICTORIA VALDERRAMA. "3D PORE PRESSURE MODELING FROM WELL DATA". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2009. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=15134@1.
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AGÊNCIA NACIONAL DE PETRÓLEOA modelagem tridimensional (3D) de gradiente de pressões de poros geralmente é feita utilizando dados sísmicos e calibrada com dados de poços, não sendo comum na indústria de petróleo a geração de modelos 3D baseados exclusivamente em dados de poços. A utilização de dados de poços para modelos unidimensionais do gradiente de pressão de poros, contudo, é trivial. Neste trabalho são apresentadas modelagens 3D de pressão de poros pelo método de Eaton e pelo método de Bowers, exclusivamente a partir de dados de poços (14) de um campo brasileiro. A metodologia utilizada foi baseada no programa Drillowrks 3D, da Knowledge Systems, sendo considerado apenas o fenômeno da subcompactação como possível mecanismo gerador das sobrepressões. Embora os dados sísmicos sejam os mais usados na indústria de petróleo e gás para a modelagem 3D de pressão de poros, um estudo de caso apresentado neste trabalho mostra que o uso de dados de poços para a modelagem 3D de pressão de poros é satisfatório, atingindo-se erros inferiores a 1ppg para ambas as metodologias, em relação a medidas diretas de pressão de poros.
Tridimensional (3D) modeling of pore pressure gradient is usually based on seismic data and calibrated with well data. Tridimensional models based exclusively in well data are not common in the oil industry. However, well data are regulary used to derive unidimensional models of the pore pressure gradient. The current work presents 3D models of pore pressure gradient using the Eaton method and Bowers method, derived from 14 wells data in a Brazilian field. The methodology used was based in the software Drillowrks 3D, from Knowledge Systems. The undercompaction mechanism was considered as the overpressure generator. Although the seismic data are the most commonly used in oil and gas industry for 3D pore pressure modeling, a case study presented herein shows that using wells data for 3D pore pressure modeling is satisfactory, with errors less than 1ppg in both methods in respect to direct measurements of pore pressure.
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Gaber, Ahmed Yaseen 1962. "Pore-water pressure debonding of asphaltic concrete". Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277077.
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The report presents an evaluation of a modification to an asphalt-debonding test procedure when used with a water debonding apparatus developed at the University of Arizona, the Pore-Water Pressure Debonding Device. The method being modified is that outlined by Jimenez in his report "Testing for Debonding of Asphalt from Aggregates". A regular test specimen, 4 inches in diameter by 2½ inches high, is water-saturated at 122°F and subjected to repeated pore-water pressure varying from 5 to 30 psi. The above factors are kept constant and the following ones are varied: air void content, stress frequency, stress repetition, stress duration and testing temperature. Test results of the modified testing procedure demonstrated the following trend: the higher the value of any of the aforementioned test variables, i.e., the void content, stress frequency, stress repetition, or stress duration, or any combination of these variables, the greater the loss of the mix resistance to stripping.
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Larson-Robl, Kylie M. "PORE PRESSURE MEASUREMENT INSTRUMENTATION RESPONSE TO BLASTING". UKnowledge, 2016. http://uknowledge.uky.edu/mng_etds/30.
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Coal mine impoundment failures have been well documented to occur due to an increase in excess pore pressure from sustained monotonic loads. Very few failures have ever occurred from dynamic loading events, such as earthquakes, and research has been done regarding the stability of these impoundment structures under such natural seismic loading events. To date no failures or damage have been reported from dynamic loading events caused by near-by production blasting, however little research has been done considering these conditions. Taking into account that current environmental restrictions oblige to increase the capacity of coal impoundments, thus increasing the hazard of such structures, it is necessary to evaluate the effects of near-by blasting on the stability of the impoundment structures. To study the behavior of excess pore pressure under blasting conditions, scaled simulations of blasting events were set inside a controlled sand tank. Simulated blasts were duplicated in both saturated and unsaturated conditions. Explosive charges were detonated within the sand tank at various distances to simulate different scaled distances. Information was collected from geophones for dry and saturated scenarios and additionally from pressure sensors under saturated conditions to assess the behavior of the material under blasting conditions.
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O'Donnell, Christopher. "The effect of pore pressure on sediment transport". Thesis, University of Liverpool, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.399157.
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Li, Kim Mui S. T. "Pore pressure in concrete : theory and triaxial tests". Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233289.
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Bernabé, Yves. "Permeability and pore structure of rocks under pressure". Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/57818.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1986.Microfiche copy available in Archives and Science
Includes bibliographies.
by Yves Bernabe.
Ph.D.
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Vestman, Marcus. "Modeling of pore pressure in a railway embankment". Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-71373.
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LKAB and Trafikverket want to increase the maximum allowed axial load from 30 tons to 32,5 tons for the northern part of Malmbanan. There are ongoing investigations of the condition of the railway with the current axial load of 30 tons. The investigations do not include one of Trafikverket's concerns about the condition of the railway. That question is how the periodical load from trains affect the stability and maintenance cost of the railway embankment. The aim of this thesis is therefore to do a preliminary investigation of how the excess pore pressure is developed in the railway embankment during periodical loading and an attempt to model it the help of PLAXIS2D, a finite element software. PLAXIS2D has been used to model a simplified section of section km 1449+820 that is subjected by periodical loading with an axial load of 30 tons. There are 6 created models in the thesis where model 2-6 origin from model 1 but with some minor changes. The changes between the models are the train speed, groundwater level, width of the embankment and load. The periodical load applied in all models has been assumed to load the embankment with a periodical shape of a sinus curve. From the models, the distribution of the effective stress and excess pore pressure have been measured. The total displacement and the magnitude of excess pore pressure in different measuring points in the embankment have also been measured. These results have been used to analyze why there are certain points in the embankment which accumulate excess pore pressure. In the models, measuring points have also been created beneath the sleeper and in the embankment toe where total displacement and effective stress have been measured to relate and see if the response in stress and displacements are trustworthy. It was concluded that accumulation of excess pore pressure is relative high in the embankment toe due to the stress distribution and slope stability. The embankment is developing large shear stresses in the embankment toe to resist against slope failure. The excess pore pressure is recommended to be measured in the embankment toe, but it is also recommended to develop the model further since it does not consider any dynamics and neither soil stiffening or soil softening which limit the possibility to analyze liquefaction in detail.
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White, Adrian James. "Minimum stress and pore fluid pressure in sedimentary basins". Thesis, Durham University, 2001. http://etheses.dur.ac.uk/3879/.
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Leak-off pressures (LOPs) recorded during leak-off tests (LOTs) conducted down boreholes are often used to estimate the magnitude of the minimum stress (usually assumed to be horizontal – S(_h)) in the subsurface. However, the reliability of these tests has previously been questioned in the literature and the accuracy of the data obtained from them has been in doubt. Using original LOT data from Mid-Norway, this study has shown that through stringent quality control, good LOT data can be used to accurately constrain the magnitude of S(_h). Knowledge of the relationship between in-situ stress and pore pressures (Pp) in basins provides insights into their structure as well as having implications for well design and drilling safety. Using stress-depth plots to display S(_h) measurements from Mid-Norway and six further basins from around the world reveals a variability in the magnitude of Sh at all depths. Analyses show that rock mechanical properties or differences in the way LOTs are performed cannot explain this variability. Separate analysis of extended leak-off test (XLOT) data from Mid-Norway shows that variability in the magnitude of the LOP (most often used to calculate S(_h)) is inherent in the testing procedure. This inherence suggests either the variations in Sh are real (they represent basin heterogeneities) or that they result from a combination or rock mechanical and/or pumping pressure test parameters. Further use of multiple cycle XLOTs shows that using LOPs and instantaneous shut-in pressures (ISIPs) to calculate S(_h) produces similar results. Considering re-opening cycles of tests and those tests from greater depths shows the difference between the magnitude of Sh calculated using the LOP and ISIP is reduced. These same high quality data have been used to calculate the magnitude of the three principal stress from Mid-Norway and show the contemporary stress situation to be S(_h)
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Henderson, Elizabeth. "Evaluation of the time response of pore pressure measurements". Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/37743.
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Wiggan, Clive. "Long-term pore water pressure changes around subsurface structures". Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/362643/.
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Geotechnical engineering guidelines mandate the use of the most onerous hydraulic criteria for the design of earth retaining structures below the water table. Consequently, favourable local conditions, including the geometry of the structure, are not usually exploited. This means that retaining walls in particular are typically designed to resist hydrostatic pressures below the water table. Investigations have shown however that pore water pressures, axial stresses and bending moments reduce when groundwater seepage is allowed through the segmented linings of shallow tunnels. Contiguous pile retaining walls, by their nature, are also permeable. Allowing for groundwater seepage through the gaps in a retaining wall formed from contiguous piles could result in the pore water pressures on the active side of the wall being less than behind conventional impermeable retaining walls such as diaphragm walls. Numerical simulations, laboratory flow tank experiments and long-term field monitoring were conducted to determine the impact of pile gaps on the hydraulic conditions around contiguous piles. A relationship between the resulting bulk permeability of the equivalent structure and the pile gap was derived from 2D numerical analyses and verified by flow tank experiments. This expression can be used to calculate bulk permeability values for uniform retaining walls representing circular piles in 2D numerical simulations. The permeability relationship was used to calculate and assign equivalent bulk permeability values for a continuous retaining wall of uniform cross-section during the back analysis of the hydraulic conditions around the contiguous pile retaining wall at CTRL, Ashford. Pore water pressures and horizontal total stresses from the back analyses were consistent with those from the field measurements but were much lower than behind retaining walls formed from secant piles in similar conditions. Dimensionless charts were presented to estimate the groundwater level and the increased settlement observed behind contiguous pile retaining walls. The results demonstrated that the economic advantages of allowing through-wall seepage are greater than the perceived disadvantages.
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Kvam, Øyvind. "Pore pressure estimation from single and repeated seismic data sets". Doctoral thesis, Norwegian University of Science and Technology, Department of Petroleum Engineering and Applied Geophysics, 2005. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-509.
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Høye poretrykk utgjør en risiko for boreoperasjoner på Norsk Sokkel og internasjonalt. Denne risikoen kan reduseres dersom man har kjennskap til poretrykksforholdene før boring. Poretrykk er også en viktig parameter for felt i produksjon, og kunnskap om hvordan dette utvikler seg over tid vil kunne ha stor betydning for økt oljeutvinning. Seismiske data inneholder informasjon om poretrykket og kan derfor bidra til økt kunnskap på dette området. Avhandlingen tar for seg hvordan hastighets- og amplitudeinformasjon fra seismiske data kan brukes for å estimere poretrykk.
Abnormally high pore pressures in the subsurface pose a hazard to drilling operations worldwide. The problem is not unusual on the Norwegian Continental Shelf. Knowledge of the pore pressure prior to drilling may reduce the risk related to drilling in high pressure zones. Pore pressure is also a vital paramter for producinig fields, and knowledge of how the pressure develops over time can be important for increased oil recovery. Seismic data contain information on the pore pressure and may contribute to increased understanding of subsurface pressure conditions. The thesis deals with methods for estimation of pressure from seismic velocity and amplitude data.
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Stunes, Sindre. "Methods of Pore Pressure Detection from Real-time Drilling Data". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for petroleumsteknologi og anvendt geofysikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18899.
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The knowledge of formation pore pressure, and how it changes throughout the length of a well, is crucial in terms of maintaining control of the wellbore. Failure to recognize deviations from the expected pressures can lead to problems and instabilities, which increases drilling costs. A worst case scenario may lead to loss of an entire well section. Thus maintaining a real-time knowledge of the formation pore pressure is beneficial regarding both the cost and the safety of a drilling operation.In this thesis multiple methods of pore pressure detection have been implemented in a Matlab program, which is used for testing with recorded real-time drilling data of a well, provided by IPT. The methods chosen were the Zamora and Eaton methods, both based on utilization of the dc-exponent, and the Bourgoyne-Young drilling model. The program has calculated pore pressure gradients based on each of these methods. In turn these results have been compared with the pore pressure presented in a final well report provided alongside the drilling data. This forms a basis for evaluation of each methods accuracy and applicability with use of this kind of drilling data. The results show that all three methods are able to produce a pore pressure gradient which is partly in compliance with the values provided in the final well report. However, the accuracy of the calculated results is not sufficient to be used to detect pore pressure with the desired precision. This may in part be caused by a lack of gamma ray data, which would have provided a more reliable selection of data. The addition of gamma ray as an input parameter should be of priority in any future developments. The most accurate result was calculated using the Bourgoyne-Young drilling model.
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Gonçalves, Correia Ricardo Nuno. "Development of a pore pressure sensor employing fibre Bragg gratings". Thesis, Cranfield University, 2008. http://hdl.handle.net/1826/3758.
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Monitoring pore pressure is important to understand and predict the mechanical
behaviour of soil, helping engineers to assess the stability of slopes and built
infrastructures. The instrumentation used to monitor pore pressure should provide dense
or extended spatial monitoring of the pore pressure and facilitate multiplexing with
other sensors to form a multi-parameter monitoring system. The aim of this research
was to develop a Fibre Bragg Grating (FBG) pore pressure sensor for soil applications,
satisfying the typical measurement requirement of 1 kPa resolution over a 300 kPa
measurement range with the potential for multiplexing. The technique used to develop
the sensor consisted of transducing pressure into a transverse load applied to the central
section of an FBG. This loading configuration induces a narrow spectral drop-out in the
reflection spectrum of the FBG that tracks across its bandwidth in response to the
applied load. The effect of this loading configuration on the reflection spectrum of a
bare FBG was modelled with the aim of optimising the sensor range and resolution. An
improvement of the sensor sensitivity to transverse load was obtained using a novel
packaging technique that consisted of embedding the central section of the FBG within
an epoxy cube. The deformation of the epoxy cube in response to transverse load
resulted in the application of an axial strain to the embedded section of the FBG, which
improved the load sensitivity. Moreover, this technique provided an efficient protection
of the fibre against mechanical damage. A sensor housing was designed to allow the
amplification/reduction of the load resulting from the pressure applied to a diaphragm.
A pressure resolution of 0.2 kPa over a 100 kPa measurement range was obtained using
a 6 mm long FBG with a 2 mm long section embedded in a epoxy cube which satisfies
the sensor requisites.
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Lee, Jangguen. "The Behavior of Pore Water Pressure in Cohesive Subgrade Soils". The Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1364216774.
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Fang, Chao. "Pore-scale Interfacial and Transport Phenomena in Hydrocarbon Reservoirs". Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/89911.
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Exploring unconventional hydrocarbon reservoirs and enhancing the recovery of hydrocarbon from conventional reservoirs are necessary for meeting the society's ever-increasing energy demand and requires a thorough understanding of the multiphase interfacial and transport phenomena in these reservoirs. This dissertation performs pore-scale studies of interfacial thermodynamics and multiphase hydrodynamics in shale reservoirs and conventional oil-brine-rock (OBR) systems.
In shale gas reservoirs, the imbibition of water through surface hydration into gas-filled mica pores was found to follow the diffusive scaling law, but with an effective diffusivity much larger than the self-diffusivity of water molecules. The invasion of gas into water-filled pores with width down to 2nm occurs at a critical invasion pressure similar to that predicted by the classical capillary theories if effects of disjoining pressure and diffusiveness of water-gas interfaces are considered. The invasion of oil droplets into water-filled pores can face a free energy barrier if the pressure difference along pore is small. The computed free energy profiles are quantitatively captured by continuum theories if capillary and disjoining pressure effects are considered. Small droplets can invade a pore through thermal activation even if an energy barrier exists for its invasion.
In conventional oil reservoirs, low-salinity waterflooding is an enhanced oil recovery method that relies on the modification of thin brine films in OBR systems by salinity change. A systematic study of the structure, disjoining pressure, and dynamic properties of these thin brine films was performed. As brine films are squeezed down to sub-nanometer scale, the structure of water-rock and water-oil interfaces changes marginally, but that of the electrical double layers in the films changes greatly. The disjoining pressure in the film and its response to salinity change follow the trend predicted by the DLVO theory, although the hydration and double layer forces are not simple additive as commonly assumed. A notable slip between the brine film and the oil phase can occur.
The role of thin liquid films in multiphase transport in hydrocarbon reservoirs revealed here helps lay foundation for manipulating and leveraging these films to enhance hydrocarbon production and to minimize environmental damage during such extraction.Doctor of Philosophy
Meeting the ever-increasing energy demand requires efficient extraction of hydrocarbons from unconventional reservoirs and enhanced recovery from conventional reservoirs, which necessitate a thorough understanding of the interfacial and transport phenomena involved in the extraction process. Abundant water is found in both conventional oil reservoirs and emerging hydrocarbon reservoirs such as shales. The interfacial behavior and transport of water and hydrocarbon in these systems can largely affect the oil and gas recovery process, but are not well understood, especially at pore scale. To fill in the knowledge gap on these important problems, this dissertation focuses on the pore-scale multiphase interfacial and transport phenomena in hydrocarbon reservoirs. In shales, water is found to imbibe into strongly hydrophilic nanopores even though the pore is filled with highly pressurized methane. Methane gas can invade into water-filled nanopores if its pressure exceeds a threshold value, and the thin residual water films on the pore walls significantly affect the threshold pressure. Oil droplet can invade pores narrower than their diameter, and the energy cost for their invasion can only be computed accurately if the surface forces in the thin film formed between the droplet and pore surface are considered. In conventional reservoirs, thin brine films between oil droplet and rock greatly affect the wettability of oil droplets on the rock surface and thus the effectiveness of low-salinity waterflooding. In brine films with sub-nanometer thickness, the ion distribution differs from that near isolated rock surfaces but the structure of water-brine/rock interfaces is similar to their unconfined counterparts. The disjoining pressure in thin brine films and its response to the salinity change follow the trend predicted by classical theories, but new features are also found. A notable slip between the brine film and the oil phase can occur, which can facilitate the recovery of oil from reservoirs.
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Zhang, Kaiyi. "CO2 Minimum Miscibility Pressure and Recovery Mechanisms in Heterogeneous Low Permeability Reservoirs". Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/93728.
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Benefited from the efficiency of hydraulic fracturing and horizon drilling, the production of unconventional oil and gas resources, such as shale gas and tight oil, has grown quickly in 21th century and contributed to the North America oil and gas production. Although the new enhancing oil recover (EOR) technologies and strong demand spike the production of unconventional resources, there are still unknowns in recovery mechanisms and phase behavior in tight rock reservoirs. In such environment, the phase behavior is altered by high capillary pressure owing to the nanoscale pore throats of shale rocks and it may also influence minimum miscibility pressure (MMP), which is an important parameter controlling gas floods for CO2 injection EOR. To investigate this influence, flash calculation is modified with considering capillary pressure and this work implements three different method to calculate MMP: method of characteristics (MOC); multiple mixing cell (MMC); and slim-tube simulation. The results show that CO2 minimum miscibility pressure in nanopore size reservoirs are affected by gas-oil capillary pressure owing to the alternation of key tie lines in displacement. The values of CO2-MMP from three different methods match well.
Moreover, in tight rock reservoirs, the heterogeneous pore size distribution, such as the ones seen in fractured reservoirs, may affect the recovery mechanisms and MMP. This work also investigates the effect of pore size heterogeneity on multicomponent multiphase hydrocarbon fluid composition distribution and its subsequent influence on mass transfer through shale nanopores. According to the simulation results, compositional gradient forms in heterogeneous nanopores of tight reservoirs because oil and gas phase compositions depend on the pore size. Considering that permeability is small in tight rocks and shales, we expect that mass transfer within heterogeneous pore size porous media to be diffusion-dominated. Our results imply that there can be a selective matrix-fracture component mass transfer during both primary production and gas injection secondary recovery in fractured shale rocks. Therefore, molecular diffusion should not be neglected from mass transfer equations for simulations of gas injection EOR or primary recovery of heterogeneous shale reservoirs with pore size distribution.Master of Science
The new technologies to recover unconventional resources in oil and gas industry, such as fracturing and horizontal drilling, boosted the production of shale gas and tight oil in 21st century and contributed to the North America oil and gas production. Although the new technologies and strong demand spiked the production of tight oil resources, there are still unknowns of oil and gas flow mechanisms in tight rock reservoirs. As we know, the oil and gas resources are stored in the pores of reservoir formation rock. During production process, the oil and gas are pushed into production wells by formation pressure. However, the pore radius of shale rock is extremely small (around nanometers), which reduces the flow rate of oil and gas and raises capillary pressure in pores. The high capillary pressure will alter the oil and gas phase behavior and it may influence the value of minimum miscibility pressure (MMP), which is an important design parameter for CO2 injection (an important technology to raise production). To investigate this influence, we changed classical model with considering capillary pressure and this modified model is implemented in different methods to calculate MMP. The results show that CO2 -MMP in shale reservoirs are affected by capillary pressure and the results from different methods match well. Moreover, in tight rock reservoirs, the heterogeneous pore size distribution, such as fractures in reservoirs, may affect the flow of oil and gas and MMP value. So, this work also investigates the effect of pore size heterogeneity on oil and gas flow mechanisms. According to the simulation results, compositional gradient forms in heterogeneous nanopores of tight reservoirs and this gradient will cause diffusion which will dominate the other fluid flow mechanisms. Therefore, we always need to consider molecular diffusion in the simulation model for shale reservoirs.
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Ko, Suz-chung. "Dehydration-induced pore-fluid pressure anomalies and the weakening of rocks /". [S.l.] : [s.n.], 1993. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10192.
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Gundogdu, Bora. "Relations Between Pore Water Pressure, Stability And Movements In Reactivated Landslides". Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12612967/index.pdf.
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Slope movements cause considerable damage to life and property in Turkey as well as in the world. Although they do not typically cause loss of life, slow landslide movements can severely damage structures, interrupt the serviceability of lifelinesand, related stabilization efforts can be too costly. Most of these slow-moving landslides are reactivated landslides in stiff clays and shales, and they are mainly triggered by rainfall induced high pore water pressures. In this study, a number of reactivated, slow-moving landslide case histories with extensive pore pressure and movement data are selected for further analysis. For these landslides, the relation between pore water pressures, factor of safety and rate of movements of the slide are investigated by using limit equilibrium and finite element methods. It is found that there is a nonlinear relationship between these three variables. Sensitivity of slow moving landslides to changes in pore water pressure is developed by defining the percent change in factor of safety and percent change in pore pressure coefficient, for 10-fold change in velocity. Such relations could especially be useful in planning required level of remediation, for example, to decide on how many meters the ground water level should be lowered at a certain piezometric location, so that the stability increases to a desired level of F.S., and movement rates are reduced to an acceptable slow rate.
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Holmes, Gary John. "Early age volume change and pore pressure development in cement pastes". Thesis, Queen Mary, University of London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243815.
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TARAZONA, DARWIN CLEMENTE MATEUS. "PORE PRESSURE ESTIMATION IN THE GUAJIRA BASIN, COLOMBIA, USING BASIN MODELING". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2013. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=23880@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
A caracterização das pressões de poros nas bacias sedimentares marinhas é fundamental dentro da etapa de planejamento dos projetos de perfuração na indústria do Petróleo. Uma vez que o desconhecimento dessas pressões coloca em risco a integridade das pessoas nas sondas de perfuração, o ambiente, além de causar grandes prejuízos para as companhias. As metodologias para a estimativa das poropressões na indústria do petróleo tiveram grande desenvolvimento a partir da década de1950. Porém, a grande maioria delas não levam em consideração caraterísticas geológicas importantes como a diagêneses das rochas, as condições de contorno para o fluxo de fluidos, e os mecanismos de dissipação das sobrepressões durante o tempo geológico. Por isso, o principal objetivo do trabalho é fortalecer os estudos convencionais de estimativa de pressão de poros incluindo uma metodologia não convencional com abordagem na modelagem de bacias. Essa metodologia permite analisar o fenômeno como um sistema dinâmico, bem como levar em consideração os mecanismos de geração e de dissipação das pressões durante a evolução geológica da Bacia. Apresenta-se a descrição dos principais mecanismos de geração de sobrepressão, a teoria que descreve o fenômeno das sobrepressões, as metodologias convencionais utilizadas na indústria do petróleo e as hipóteses da metodologia baseada na modelagem de bacias. Utilizou-se o software SEMIMT, do instituto de pesquisa da Noruega, o SINTEF, para realizar a estimativa das poropressões na Bacia de Guajira, uma região offshore do norte da Colômbia. A estimativa das pressões considerou os contornos da bacia, o modelo geológico da região, o histórico de soterramento da Bacia, bem como de modelos de compactação e os modelos de fluxo vertical e fluxo horizontal dos fluidos. O resultado da estimativa das pressões permitiu definir quatro zonas com diferente grau de sobrepressão na área em estudo, que foram comparados com uma metodologia convencional, bem com dados históricos de poços perfurados na região.
Pore pressure prediction is a critical issue for well planning in the oil and gas industry. It is even more critical for offshore environments due to high risks involved in drilling operation. Blowout is the main risk regarding pore pressure since it could cause rig explosion, and oil spills to environment. Such problems can lead a successful company to a very weak position. Therefore, since the fifties, several methodologies for pore pressure prediction have been developed for the industry. Most of them just consider the mechanism of compaction as the main cause of overpressure, ignoring other factors such as rock diagenesis, boundary conditions for fluid flow, and pressure dissipation during the geologic history. That is why the main objective of this work is improving current pore pressure studies, including an alternative methodology (developed by the Norway Petroleum Research Institute - SINTEF), from a scale of basin modeling. That methodology allows analyzing the pressure phenomenon like a dynamic system, where the interaction of the overpressure and the pressure dissipation mechanisms are considered during the geological history. In this paper, main characteristics of overpressure mechanisms are briefly described as well as common methodologies used in the Oil and Gas industry for pressure prediction. Furthermore, the most important hypothesis for basing modeling methodology is described. SEMIMT software was used to predict pore pressure in Guajira Basin, an offshore region located in north Colombia. Results of basin modeling methodology allowed defining four overpressure zones which fit adequately with wells data. Besides, that result was compared with a conventional methodology. Finally, a discussion about the results is presented, highlighting the main advantages and disadvantages observed in this research.
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MARCHESI, VIVIAN RODRIGUES. "MODELING TECHNIQUES APPLIED FOR PORE PRESSURE PREDICTION IN GEOLOGICALLY COMPLEX ENVIRONMENTS". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2015. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=25745@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
O tempo não produtivo (NPT) durante a perfuração de poços de petróleo pode ser responsável pela perda de milhões de dólares em atividades offshore. A má previsão da pressão de poros pode ser uma das responsáveis pelo NPT de um poço ou mesmo sua perda definitiva em campos geologicamente complexos, como em bacias evaporíticas. Nesses campos complexos, os métodos de previsão de pressão de poros convencionais nem sempre são capazes de prever bem a distribuição de pressão de poros, mesmo após a perfuração de número considerável de poços. Este trabalho estuda técnicas alternativas que atendam ao problema de previsão de pressão para esses casos. Para fundamentar os estudos, é apresentada uma revisão sobre os riscos associados à perfuração em bacias evaporíticas e sobre os métodos de previsão de pressão existentes (métodos convencionais, sísmicos, modelagem geológica geomecânica 3D, modelagem pelo método dos elementos finitos e modelagem de bacias). Avaliando os problemas de perfuração nestes campos e as dificuldades de previsão dos métodos convencionais, nota-se que a complexidade imposta pelas consequências da presença do sal pode ser reduzida pelo uso de métodos que considerem a geologia local de forma mais abrangente em seu fluxo de trabalho. Concluiu-se que a modelagem de bacias e a modelagem geológica geomecânica 3D têm forte potencial de aplicação para estes casos. As técnicas, contudo, não tem a previsão de pressão de poros por objetivo principal, mas podem ser aplicadas ou adaptadas para tal fim. Este estudo apresenta adaptações de metodologia e/ou aplicações direcionadas de ambas para fins de previsão de pressão de poros. Para validar as propostas apresentadas, estudos de caso foram desenvolvidos e apresentaram resultados considerados bastante satisfatórios.
The non-productive time (NPT) while drilling oil and gas wells may be responsible for losing millions of dollars, especially in offshore activities. Bad pore pressure predictions may be responsible for large NPT or even the definitive loss of well in geologically complex fields, such as evaporate basins. On these complex fields, the conventional pore pressure prediction methods sometimes are not capable of providing good predictions, even if a considerable number of wells has been already drilled. This thesis studies alternative techniques which may attend for pore pressure prediction in these cases. In order to develop a consistent knowledge about the case, a literature review has been conducted in two ways: to understand what are the risks associated to drilling in evaporate basins; to review what are the available methods for pore pressure prediction (conventional methods, seismic methods, 3D geological and geomechanical modeling, finite element methods and basin modeling). During analyzing geomechanical drilling risks in these sites, and the difficulties found by conventional methods to predict it, it was noted that the complexity imposed by the presence of salt bodies can be reduced by using methods that make a strong use of geological knowledge on their workflow. It has been concluded that basin modeling and 3D geological and geomechanical modeling have a good potential to be applied for this goal. The techniques, nevertheless, do not have pore pressure prediction as their main goal, but can be applied to or adapted for such finality. This work presents some methodology adaptations and/or applications of both of techniques directed to pore pressure prediction goals. In order to validate the presented proposals, case studies has been developed, and their results were considered satisfactory.
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Rigby, Douglas Bertrand 1956. "Cyclic shear device for interfaces and joints with pore water pressure". Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276922.
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An improved multi degree-of-freedom direct shear device has been designed and constructed to test interfaces and joints under pore water pressure. Any two structural (concrete, steel, wood) or geologic (soil, rock) materials may be tested in the device as long as the top specimen is solid. The apparatus is designed to hold a 7.5-inch diameter 3-inch thick upper sample and a 9-inch diameter 3-inch thick lower sample. A normal stress of 400 psi (2.7 MPa) and a shear stress of 550 psi (3.9 MPa) can be developed at the interface. Test loading may be static, quasi-static, or cyclic, and constant or variable stiffness loading is available. A stiff reaction frame was designed to house the device and is described. The electro-hydraulic system is capable of supporting cyclic testing at 30 Hz. A new computer-controlled data acquisition and control system is also described.
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Teca, Dário Bokiló Machado. "Correction of the anisotropy in resistivity: application to pore pressure prediction". Master's thesis, Faculdade de Ciências e Tecnologia, 2014. http://hdl.handle.net/10362/13132.
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Dissertação para obtenção do Grau de Mestre em
Engenharia Geológica (Georrecursos)This dissertation is based on a curricular training period done at company Total EP Angola between July and December 2013. The data presented relate to a real case study of an exploration block, which for reasons of confidentiality is designated by Block Michocho. The fluids pressure measurement in the geological formations can be inferred from the formation resistivity log. In not perpendicular wells to the layers, resistivity curves show higher values than the expected due to the anisotropic effect of the formation thus the inference of the pressure of fluids from resistivity logs can lead to unrealistic values. Most of the developments wells drilled on Block Michocho in Angola are highly deviated, if not sub-horizontal, in the reservoir section. The objective of this work is to correct the anisotropic effect of the resistivity of Block Michocho due to non-perpendicularity of the wells when intersect the geological formations. In this study, the correction of the resistivity is based on the formula proposed by Moran and Gianzero in 1979 and involves the dipping angle of the induction logging tool and the coefficient of anisotropy of the rock formation. Prior to application of this formula for the corrections of resistivity of the Block Michocho wells logs, a set of validation tests were made. Due to lack of data on development wells (highly inclined wells) the validation test was carried out in five exploration wells where resistivity is available in the two principal directions. It was assumed that the formula would be approved for resistivity corrections if the horizontal resistivity obtained by the formula had a good correspondence with the horizontal resistivity obtained by the induction logging tool. After this validation step, the coefficient of anisotropy to be used in the formula was calibrated as well as the correction of the curves of resistivity of the remaining development wells, those much more diverted regarding the rock layers. The corrected resistivity can be applied for pore pressure prediction in low permeability rock formations, in which the main objective is to identify regions where fluid pressure is higher than normal pressure, i.e. overpressure regions. For illustration purposes, a resistivity curve from an exploration well was chosen and the pressure of the fluids in low permeability rocks was computed by using the formula proposed by Eaton in 1975. With this well data, a potential overpressure region was identified and should be avoided in drilling activities.
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Force, Erin A. (Erin Alden) 1974. "Factors controlling pore pressure generation during K₀ consolidation of laboratory tests". Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/9638.
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Kuo, Chun-Yi. "Dynamic pore pressure response of saturated Ottawa sand-shock tube tests". The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1298923141.
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Hadžalić, Emina. "Analysis of pore pressure influence on failure mechanisms in structural systems". Thesis, Compiègne, 2019. http://www.theses.fr/2019COMP2502.
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Cette thèse porte sur la sécurité globale des structures en matériaux hétérogènes saturés soumis à des charges extrêmes, et est appliquée à des problèmes d’interaction fluide-structure, tels que l’interaction barrage-réservoir. Un modèle numérique d’interaction est proposé pour prédire les principales tendances et le comportement général d’un barrage en matériau saturé en interaction avec le réservoir dans des analyses de défaillance d’intérêt pratique. Le modèle numérique proposé est d’abord présenté dans un cadre bidimensionnel (2D), puis étendu à un cadre tridimensionnel (3D). La structure est considérée comme un milieu poreux saturé constitué d’un matériau cohésif. On suppose que le fluide externe en interaction avec la structure agit comme une source de saturation des pores. La réponse de la structure en matériau saturé est décrite avec un modèle lattice discrete couplé de type poutre, basé sur la discrétisation du domaine avec la tessellation de Voronoï, où les liens cohésifs sont représentés par des poutres de Timoshenko non linéaires avec un champ de déplacements enrichi en termes de discontinuités fortes. Le couplage entre la phase solide et le fluide dans les pores est traité avec la théorie de Biot et la loi de Darcy décrivant l’écoulement d’un fluide à travers d’un milieu poreux. La prise en compte numérique du couplage interne ajoute un degré de liberté supplémentaire du type pression à chaque nœud de l’élément fini de Timoshenko, qui est ensuite utilisé pour résoudre les problèmes d’interface entre la structure et le fluide. On considère que le fluide externe dans le réservoir est limité à des petits mouvements, ce qui nous permet de le modéliser avec la théorie des ondes acoustiques. Pour cela, la formulation lagrangienne avec l’approximation mixte déplacement-pression est choisie. Le traitement de l’interface fluide-structure dans le modèle numérique d’interaction est résolu d’une manière simple et efficace. Notamment, les éléments finis de la structure et du fluide externe partagent les mêmes degrés de liberté dans les nœuds communs, permettant ainsi la résolution du système d’équations avec une approche de calcul monolithique. Toutes les implémentations et les simulations numériques sont effectués avec la version recherche du code informatique FEAP (Finite Element Analysis Program). Les modèles numériques proposés pour la structure, le fluide externe et le modèle d’interaction sont validés dans le régime élastique linéaire en comparant les résultats calculés avec les valeurs de référence obtenues soit avec des solutions analytiques, soit avec des modèles continus. Les simulations numériques dans le régime non linéaire ont comme but de démontrer les capacités du modèle proposé de capturer la réponse complète à l’échelle macro et les mécanismes de rupture des structures en matériaux saturés. Enfin, la capacité du modèle d’interaction proposé de traiter la défaillance localisée progressive d’un barrage construit en matériau cohésif poreux sous l’interaction barrage-réservoir a été testé pour un programme de chargement spécifique. Pour prendre en compte les effets de la température, le couplage thermique est introduit dans le modèle numérique de la structureThis thesis studies the issue of the overall safety of structures built of heterogeneous and pore-saturated materials under extreme loads in application to fluid-structure interaction problems, such as the dam-reservoir interaction. We propose a numerical model of interaction capable of predicting main tendencies and overall behavior of pore-saturated dam structure interacting with the reservoir in failure analyses of practical interest. The proposed numerical model is first presented in two-dimensional (2D) framework and later extended to three-dimensional (3D) framework. We consider the structure built of porous cohesive material. We assume that the external fluid in interaction with the structure acts as a source of pore saturation. We model the response of the pore-saturated structure with the coupled discrete beam lattice model based on Voronoi cell representation of domain with inelastic Timoshenko beam finite elements enhanced with additional kinematics in terms of embedded strong discontinuities acting as cohesive links. The coupling between the solid phase and the pore fluid is handled with Biot’s porous media theory, and Darcy’s law governing the pore fluid flow. The numerical consideration of internal coupling results with an additional pressure-type degree of freedom placed at each node of the Timoshenko beam finite element, which is later used at the fluidstructure interface. The confined conditions met for external fluid placed in the reservoir enable the modeling of external fluid motion with the acoustic wave theory. For the numerical representation of the external fluid limited to small (irrotational) motion, we choose a Lagrangian formulation and the mixed displacement/pressure based finite element approximation. The end result are the displacement and pressure degrees of freedom per node of external fluid finite elements, which allows for the issue of the fluid-structure interface to be solved in an efficient and straightforward manner by directly connecting the structure and external fluid finite elements at common nodes. As a result, all computations can be performed in a fully monolithic manner. All numerical implementations and computations are performed with the research version of the computer code FEAP (Finite Element Analysis Program). The proposed numerical models of structure, external fluid and ultimately numerical model of interaction are validated in the linear elastic regime of structure response by comparing computed results against reference values obtained either with analytical solutions or continuum models. The numerical simulations in the nonlinear regime of structure response are performed with the aim to demonstrate the proposed coupled discrete beam lattice model capabilities to capture complete macro-scale response and failure mechanisms in pore-saturated structures. Finally, the proposed numerical model of interaction ability to deal with the progressive localized failure of a dam structure built of porous cohesive material under damreservoir interaction for a particular loading program was tested. To account for the temperature effects, the thermal coupling is introduced in the numerical model of the structure
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Karlson, Tait K. "Evaluation of cyclic pore pressure induced moisture damage in asphalt pavement". [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0012162.
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Frank, Jeffrey Wade. "Developing an enhanced triaxial testing system with cyclic pore-pressure capabilities". [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0003561.
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William, Henry Schulz. "Beyond Hydrostatic Pore-Water Pressure - Variable Effects of Groundwater on Landslide Initiation and Mobility". Doctoral thesis, Kyoto University, 2020. http://hdl.handle.net/2433/245815.
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Soeller, Christopher Philip. "Investigation of the Hydromechanical Effects of Lithostatic Unloading in Open-pit Mines". Thesis, Boston College, 2016. http://hdl.handle.net/2345/bc-ir:107281.
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Thesis advisor: Alan KafkaThe stability of open-pit mine walls and other geotechnical infrastructure is a function of geometry, material properties and groundwater conditions (pore pressure distribution). A portion of failures are attributed to the effect of pore water pressures within the mine wall slopes. The objective of this research was to investigate the interaction between the increments/decrements of stresses that occur during the lithostatic unloading/excavation of the pit and the increments/decrements of pore water pressures. This interaction can be described by the theory of linear poroelasticity, which incorporates the coupling between changes in fluid pressure and changes in stress in porous media. The results of this thesis are displayed in the form of contour charts and graphs
Thesis (MS) — Boston College, 2016
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Earth and Environmental Sciences
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Junaideen, Sainulabdeen Mohamed. "Failure of saturated sandy soils due to increase in pore water pressure". Thesis, Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B30708540.
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Carter, Barton P. "Effect of Pore Size and Thickness on Critical Pressure of Elastic Systems". Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7216.
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Significant energy savings can be achieved by improving efficiency of water removal in the press section of a paper machine, rather than energy-intensive evaporative dryer cans. Impulse drying is a novel technology to remove water from the sheet in the press section by using a heated press roll.
Delamination is a major challenge to be overcome before impulse drying can be implemented successfully. Delamination is caused by a region of high temperature liquid water under high pressure in the press. Upon exiting the nip, the pressure drops and the high temperature water flashes to steam. If the expansion of the steam is too strong, the bonds between the fibers will fail and a blister will form. The formation of this blister is characteristic of delamination.
The goal of this project was to understand the internal mechanics of a wet web as it exits the nip of an impulse dryer. In this way, the components of the sheet can be tailored to open the operating window of impulse drying. A mathematical model, developed to describe the deflection and delamination of an elastic membrane, was utilized in this work. Three failure criteria were employed to represent delamination of this pliable membrane from the more rigid sub layers in the sheet.
The experimental portion of this effort was devoted to showing the validity of these models and which was the best fit. A series of experiments were employed to validate the model. A peel test was used to determine the amount of work needed to pull a membrane from a rigid substrate. Pressurized blister experiments were conducted to find the relationship between critical pressure and initial defect size. The predictions from the mathematical model were then compared to these experimental values. Finally, work was done to understand the physics of the delamination of a porous membrane.
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Garcia-Aleman, Jesus Dickson James M. "Mathematical modeling of the pressure-driven performance of McMaster pore-filled membranes /". *McMaster only, 2002.
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Chen, Barry Shiyo. "Profiling stress history of clays using piezocones with dual pore pressure measurements". Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/21504.
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HOLZBERG, BRUNO BROESIGKE. "PROBABILISTIC PORE PRESSURE PREDICTION IN RESERVOIR ROCKS THROUGH COMPRESSIONAL AND SHEAR VELOCITIES". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2005. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=7987@1.
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AGÊNCIA NACIONAL DE PETRÓLEOEsta tese propõe uma metodologia de estimativa de pressão de poros em rochasreservatório através dos atributos sísmicos velocidade compressional V(p) e velocidade cisalhante V(s). Na metodologia, os atributos são encarados como observações realizadas sobre um sistema físico, cujo comportamento depende de um determinado número de grandezas não observáveis, dentre as quais a pressão de poros é apenas uma delas. Para estimar a pressão de poros, adota-se uma abordagem Bayesiana de inversão. Através de uma função de verossimilhança, estabelecida através de um modelo de física de rochas calibrável para a região, e do teorema de Bayes, combina- se as informações pré-existentes sobre os parâmetros de rocha, fluido e estado de tensões com os atributos sísmicos observados, inferindo probabilisticamente a pressão de poros. Devido a não linearidade do problema e ao interesse de se realizar uma rigorosa análise de incertezas, um algoritmo baseado em simulações de Monte Carlo (um caso especial do algoritmo de Metropolis- Hastings) é utilizado para realizar a inversão. Exemplos de aplicação da metodologia proposta são simulados em reservatórios criados sinteticamente. Através dos exemplos, demonstra-se que o sucesso da previsão de pressão de poros depende da combinação de diferentes fatores, como o grau de conhecimento prévio sobre os parâmetros de rocha e fluido, a sensibilidade da rocha perante a variação de pressões diferenciais e a qualidade dos atributos sísmicos. Visto que os métodos existentes para previsão de pressão de poros utilizam somente o atributo V(p) , a contribuição do atributo V(s) na previsão é avaliada. Em um cenário de rochas pouco consolidadas (ou em areias), demonstra-se que o atributo V(s) pode contribuir significativamente na previsão, mesmo apresentando grandes incertezas associadas. Já para um cenário de rochas consolidadas, demonstra-se que as incertezas associadas às pressões previstas são maiores, e que a contribuição do atributo V(s) na previsão não é tão significativa quanto nos casos de rochas pouco consolidadas.
This work proposes a method for pore pressure prediction in reservoir rocks through compressional- and shear-velocity data (seismic attributes). In the method, the attributes are considered observations of a physic system, which behavior depends on a several not-observable parameters, where the pore pressure is only one of these parameters. To estimate the pore pressure, a Bayesian inversion approach is adopted. Through the use of a likelihood function, settled through a calibrated rock physics model, and through the Bayes theorem, the a priori information about the not-observable parameters (fluid and rock parameters and stress state) is combined with the seismic attributes, inferring probabilistically the pore pressure. Due the non-linearity of the problem, and due the uncertainties analysis demanding, an algorithm based on Monte Carlo simulations (a special case of the Metropolis- Hastings algorithm) is used to solve the inverse problem. The application of the proposed method is simulated through some synthetic examples. It is shown that a successfully pore pressure prediction in reservoir rocks depends on a set of factors, as how sensitive are the rock velocities to pore pressure changes, the a priori information about rock and fluid parameters and the uncertainties associates to the seismic attributes. Since the current methods for pore pressure prediction use exclusively the attribute compressional velocity V(p), the contribution of the attribute shear velocity V(s) on prediction is evaluated. In a poorly consolidated rock scenario (or in sands), the V(s) data, even with great uncertainties associated, can significantly contribute to a better pore pressure prediction. In a consolidated rock scenario, the uncertainties associated to pore pressure estimates are higher, and the s V data does not contribute to pore pressure prediction as it contributes in a poorly consolidated rock scenario.
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Gamage, Kusali R. "Permeabilities of subduction zone sediments and their effect on pore pressure generation". [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0013080.
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Uchechukwu, Ekwo Ernest. "Pore pressure prediction: a case study of sandstone reservoirs, Bredasdorp basin, South Africa". Thesis, University of the Western Cape, 2014. http://hdl.handle.net/11394/4228.
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Masters of ScienceThe Bredasdorp basin is situated off the south coast of the Republic of South Africa, southeast of Cape Town and west-south-west of Port Elizabeth. It covers approximately 18,000 sq. km beneath the Indian Ocean along the southern coast of South Africa, which is in the southwest of Mosselbay. Bredasdorp basin contains South Africa’s only oil and gas production facilities and has been the main focus for oil and gas exploration in South Africa. It is one of the largest hydrocarbon producing block in South Africa, rich in gas and oil prone marine source rocks of kimmeridgian to berriasian age. The wells of interest for this study are located within block 9 which is made up of 13 wells but for this study the focus is only on 3 wells, which are well F-01,F-02 and F-03. The goal of this study is to predict as accurately as possible the areas within and around the sandstone reservoir intervals of these wells with abnormal pressure, using well logs and production test data. Abnormal pore pressure which is a major problem for drillers in the oil industry can cause serious drilling incidents and increase greatly drilling non-production time if the abnormal pressures are not predicted accurately before and while drilling. Petrophysics log analysis was done to evaluate the reservoirs. The intervals of the reservoir are the area of interest.Pore pressure gradient, fracture gradient, pore pressure and fracture pressure model were run. Pressures of about 6078.8psi were predicted around the zone of interest in well F-01, 7861 psi for well F-02 and 8330psi for well F-03. Well F-03 was the most pressured of the three wells. Abnormal pressures were identified mostly at zones above and below the area of interest and predicted pressure values were compared to actual pressure values to check for accuracy.
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Fritzson, Hanna. "Effect of Environmental Factors on Pore Water Pressure in River Bank Sediments, Sollefteå, Sweden". Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-333788.
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Pore water pressure in a silt slope in Sollefteå, Sweden, was measured from 2009-2016. The results from2009-2012 were presented and evaluated in a publication by Westerberg et al. (2014) and this report is an extension of that project.In a silt slope the pore water pressures are generally negative, contributing to the stability of theslope. In this report the pore water pressure variations are analyzed using basic statistics and a connection between the pore water pressure variations, the geology and parameters such as temperature, precipitation and soil moisture are discussed.The soils in the slope at Nipuddsvägen consists of sandy silt, silt, clayey silt and silty clay. The main findings were that at 2, 4 and 6 m depth there are significant increases and decreases in the pore water pressure that can be linked with the changing of the seasons, for example there is a significant increase in the spring when the ground frost melts. As the seasons change, so do the temperature and amount and type of precipitation. Other factors that vary with the season are the amount of net radiation, wind speed and relative humidity, all of which affect the amount of evapotranspiration. At greater depths the pore water pressue is most likely affected by a factor/factors that varies from year to year, possibly the total amount of rainfall. Therefore, the anticipated increase in precipitation in Scandinavia due to climate change could be an important factor influencing slope stability.What precipitation, temperature and evapotranspiration have in common is that they affect the amount of water infiltrating the soil, and thereby the soil moisture content. How the soil moisture is distributed and flows through the soil (sub-surface flow) is governed by the different soil types and their mutual order in the slope, as well as by factors affecting the structure of the soil, e.g. animal burrows and aggregation. The formation of ground frost also affects the way in which the water present in the soil is redistributed.At c. 14 m depth in the slope, there is a saturated layer with positive pore water pressures, which could be one of several such layers. The overall groundwater situation in a silt slope is complex; several different bodies of water can develop, and to get a complete picture of the ground water situation (andthereby also the pore water pressure variations) thorough hydrological surveys are needed.Under 2009-2016 mättes porvattentrycket i en siltslänt i Sollefteå. Resultaten från 2009-2012presenterades och utvärderades i en publikation av Westerberg et al. (2014) och detta examensarbete är en förlängning av det projektet.I en siltslänt är porvattentrycket vanligtvis negativt vilket bidrar till stabiliteten i slänten. I den härrapporten är variationerna av porvattentrycket analyserade med hjälp av enkel statistik och en koppling mellan variationerna och geologin samt parametrar så som temperatur, nederbörd och fukthalt i marken diskuteras.Jordarterna i slänten vid Nipuddsvägen består av sandig silt, silt, lerig silt och siltig lera. Slutsatsen var att på 2, 4 och 6 m djup ökade och minskade porvattentrycket med årstiderna, till exempel ökade porvattentrycket signifikant vid tjällossningen. När årstiderna skiftar ändras även temperaturen och mängden, och typen, av nederbörd. Andra faktorer som varierar över året är netto-instrålningen, vindhastigheten och den relativa fuktigheten och dessa faktorer påverkar i sin tur evapotranspirationen. På större djup beror antagligen portrycksvariationerna på någon eller några faktorer som skiljer sig åt från år till år, möjligtvis den totala mängden nederbörd. Därmed skulle den ökade nederbörd som förväntas i Skandinavien på grund av klimatförändringarna kunna påverka släntstabiliteten.Vad nederbörd, temeperatur och evapotranspiration har gemensamt är att de påverkar mängden vatten som infiltrerar marken, det vill säga de påverkar markens fukthalt. Hur vattnet är födelat i marken beror på de olika jordarterna och deras inbördes ordning i slänten, men också av faktorer som påverkar markens struktur så som aggregation och uppluckring av jorden på grund av marklevande djurs aktivitet. Även formationen av tjäle på vintern har troligtvis en viss inverkan på hur vattnet i marken omfördelas.På 14 m djup finns ett vattenmättat lager med positiva porvattentryck vilket skulle kunna vara ett av flera sådana lager. I en siltslänt är grundvattensituationen mycket komplex, flera magasin av vatten kan bildas. För att få en bra bild av grundvattensituationen (och där med också porvattentrycksvariationerna)behöver noggranna hydrologiska undersökningar genomföras.
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Bailey, Nicholas David. "Development and testing of experimental equipment to measure pore pressure and dynamic pressure at points outside a pipe leak". Master's thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/13655.
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Includes bibliographical references.Leaks in water distribution mains are a major issue throughout the world. The amount of water lost through these leaks is unacceptable for a resource, which is becoming ever scarcer. Little is known about the fundamentals, which exist outside leaking water distribution mains. The se fundamentals are the interaction between the leaking water and the soil surrounding the distribution main. This interaction is known as the leak - soil interaction. Research has found that a phenomenon called internal fluidisation typically occurs in the soils outside of leaks in distribution mains. Internal fluidisation is a complex interaction between the leak and the surrounding soil, whereby the soil losses its intermolecular bonding and becomes displaced by the water jet generated by the leak. It is believed that this complex phenomenon causes large energy losses. Subsequently, many water leaks are not able to propagate to the ground surface where they will be visible. This leads to many such leaks being undetected below the ground surface. The objective of this study was to develop an experimental setup, which simulated the internal fluidisation phenomenon. The setup consisted primarily of an orifice, simulating a leak in a distribution pipe; surrounded by ballotini (glass beads), as the soil medium surrounding the pipe; and the measurement instruments, which were Pitot tubes. When using the experimental setup, pore pressures and dynamic pressures around the leak and therefore within the ballotini bed were measured using two Pitot tubes. The accuracy and repeatability of these measurements were also of importance and were investigated. The accuracy of the measurements were dependant on the precision of the Pitot tubes in taking measurements. They were found to have an error of up to 4.1 %, although the experiment to test for the accuracy was not fool proof. The repeatability of the measurements was found to have a 3.8 % average difference between the previous and repeated measurements. The measuring of the pore pressures and dynamic pressures resulted in the following findings, which were the most important in the study: There were large vertical velocities found in the fluidized zone, where outside of this zone they were significantly smaller. The largest pore pressure was found to occur near the top of the fluidised zone. The pore pressures in the bed from a certain distance away from the orifice had a linear distribution, illustrating that Darcy water flow was present. High energy existed in the fluidised zone where it was greatest nearest the orifice and decreased to the top of the fluidised zone. In the ballotini bed outside of the fluidised zone the energy was found to be considerably smaller and decreased further away from the orifice.
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Traugott, Martin Olson. "A surface-charge model for mudstones and the application to pore pressure prediction". Thesis, Durham University, 2005. http://etheses.dur.ac.uk/2770/.
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New geologic concepts have been developed that illuminate the critical role of bound water in the generation and prediction of overpressures in mudstones. The concept is based on new understanding of the surface-charge effects on water adsorbed on solid surfaces and comes in part from molecular modelling, atomic force measurements, and high-beam neutron diffraction studies reported in the literature. The picture that is emerging is as follows. Bound water on clay surfaces can support a lithostatic load. The bound water fraction increases with compaction, as free water is expelled, with a concomitant decrease in permeability. Overpressures commence at a threshold depth, the retention depth, where the rate of fluid loss is not sufficient to establish pressure equilibrium with the surface. With deeper burial there is a second threshold depth, a gating depth, where bound water condenses to a high-density phase. Below this gating depth, fluid expansion or other effects are responsible for secondary pressure anomalies. Knowledge of bound water effects accounts for discrepancies observed in laboratory measurements of mudstone properties. For instance, mercury intrusion and surface-area measurements depend strongly on how much (hygroscopic) bound water has-been absorbed or adsorbed on a sample before measurements. Surface charge effects tend to increase with compaction due, in part, to reduction of iron and beidellitization. A large data set for mudstones is used to show that the fraction of bound water tends to reach a maximum of almost 100 percent at a depth of 2 to 3 km. An important part of this research is the development of the empirical equation BW = 0.734 CEC (1-Փ)/Փ, where BW is bound water (fraction of total pore volume), Ф is porosity and CEC is cation-exchange capacity (expressed in meq/gm). Porosity and CEC are borehole derived using resistivity and acoustic methods described here. As an adjunct part of this research a software package (called P3) has been written that puts the concepts and relationships into practice.
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Bondino, Igor. "The application of pore-scale modelling techniques to pressure depletion in porous media". Thesis, Heriot-Watt University, 2005. http://hdl.handle.net/10399/184.
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Khan, Saadat Ali. "Pore pressure and moisture migration in concrete at high and non uniform temperatures". Thesis, King's College London (University of London), 1990. https://kclpure.kcl.ac.uk/portal/en/theses/pore-pressure-and-moisture-migration-in-concrete-at-high-and-non-uniform-temperatures(9016d00a-3f08-4eb8-a9b3-a78d405d6686).html.
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REYNA, JULIO CESAR LAREDO. "INVESTIGATION ABOUT PORE PRESSURE PREDICTION METHODS IN SHALES AND A PROBABILISTIC APPROACH APPLICATION". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2007. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=10469@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORGRUPO DE TECNOLOGIA E ENGENHARIA DE PETRÓLEO - PUC-RIO
Nos últimos 45 anos foram publicados muitos artigos referentes à previsão da pressão de poros em folhelhos, como resultado da necessidade de otimizar o processo construtivo de poços de petróleo. Neste trabalho se apresenta um panorama dos métodos de previsão de pressão de poros existentes, com suas vantagens e desvantagens, com seus pontos fortes e suas críticas, com seus acertos e não acertos; procurando explicar os motivos das diferenças entre o previsto e o real. Em geral são descritos 12 métodos de previsão de pressão de poros, além do conceito do Centróide, 3 técnicas para detectar descarga de tensões efetivas numa formação rochosa, e uma descrição do uso da sísmica na previsão da pressão de poros. Foram aplicados os métodos de Eaton (1975) e Bowers (1995) com o objetivo de fazer uma discussão sobre as incertezas presentes nos parâmetros de cada modelo, complementado o estudo com uma análise de sensibilidade. Como resultado das incertezas existentes se aplicou uma análise probabilística baseada na simulação de Monte Carlo e usando o método de Eaton, com o objetivo de apresentar resultados dentro de intervalos de confiança e permitir planos de contingência durante o projeto de construção do poço. Finalmente são avaliados os resultados de uma análise 3D de previsão de pressão de poros utilizando o modelo de Eaton e o Trend de Bowers. Os cubos de dados foram obtidos por interpolação espacial ponderada partindo de registros de poços. Os resultados mostram que este tipo de análise pode ser usado com fins qualitativos, obtendo cubos de gradientes de pressão de poros aonde se observam as zonas de maior e menor risco.
In the last 45 years were published many articles referring to shale pore pressure prediction, due to the necessity of optimizing the constructive process of petroleum wells. In this work shows up a view of the pore pressure prediction methods with its advantages and disadvantages, with its strong points and its critics, with its hits and failures, trying to explain the causes of the differences between the predicted values and the real ones. As result of the bibliographical revision, we obtained a historical of the pore pressure prediction, furthermore gathering the principal mechanisms of generation of pore pressures and mechanisms of lateral variation of the same. Also, were described 12 methods of pore pressure prediction, the Centroid concept, 3 techniques to detect unloading of effective tensions in a rock formation, and a description of the use of the seismic in the pore pressure prediction. The Eaton (1975) and the Bowers (1995) methods were applied with the objective to discuss the uncertainties in the parameters of each model, this was complemented with sensibility analysis. As result of the existent uncertainties, we applied a probabilistic analyze, based on the Monte Carlo simulation and using the Eaton´s method, with the aim to present results within confidence intervals and to allow contingency plans during the well construction project. Finally, the results of a 3D pore pressure prediction using the Eaton model and the Bowers Trend, were assessed. The data cubes were obtained by weighted space interpolation using well logs at the same basin. We concluded that the results from this type of analysis can be used such as qualitative purposes, obtaining pore pressure gradients cubes, where can be observed bigger and lesser risk zones.
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Stevens, W. Richard(William Richard). "Pore water pressure in rock slopes and rockfill slopes subject to dynamic loading". Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/191872.
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A simplified method for simulating the response of rockfill and rock slopes subject to a dynamic load is presented. A pore pressure analysis is incorporated into a dynamic slope stability computer program, the Linear Acceleration Dynamic Response of Slopes -- Multiple Degrees of Freedom (LADRS-MDF), developed by Dr. C.E. Glass of the University of Arizona. LADRS-MDF is based on Barton's empirical shear strength criteria and uses the entire acceleration time history. The dynamic water pressure analysis depends on the slope conditions. Only the transient water pressure is present in material where the excess pore pressure dissipation exceeds the excess pore pressure generation. When excess pore pressure generation is greater than the dissipation, a water pressure buildup is present along with the transient pore water pressure.
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Grant, David. "Failure mechanisms and instrumentation systems for an induced slope failure project". Thesis, University of Southampton, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243134.
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Delaney, Keegan Patrick. "Development of a One and Two-Dimensional Model for Calculating Pore Pressure in an Ablating Thermal Sacrificial Liner". Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/42438.
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Understanding the behavior of charring or decomposing materials exposed to high temperature environments is an essential aspect in rocket design. In particular, the tip of re-entry vehicles and sacrificial rocket nozzle liners are both exposed to extremely high temperatures. This thesis is specifically concerned with better understanding the reaction of sacrificial rocket nozzle liners to these high temperature environments. The sacrificial liners are designed to shield the rocket nozzle from the thermal and chemical effects of the heated exhaust gas that flows through the nozzle. However, in the design process space and weight of the rocket are at a premium. The sacrificial liners need to be designed to be as light and thin as possible, while properly shielding the nozzle from the heated exhaust gases.
The sacrificial liner material is initially impermeable in its virgin state; however, as the liner is exposed to the heated exhaust gases, it chars and the liner material begins to decompose. The decomposition of the liner by heating in the absence of oxygen is known as pyrolysis. At high temperatures, the virgin material will decompose into a solid material (charred liner) and a vapor (pyrolysis gas). The pyrolysis process leads to the flow of pyrolysis gases throughout the porous charred liner. As a result, significant pressures can build within the liner. If the pressures within the liner are high enough, mechanically weak portions of the liner may fracture and break off. Fracturing of the liner could expose the nozzle to the heated exhaust gases, thus jeopardizing the structural integrity of the nozzle. Therefore, it is important to understand the pressure distribution within the sacrificial liners that occurs as a result of the pyrolysis process.
This work describes the code PorePress, which solves for steady state and transient pressure distributions in 1- and 2-D axisymmetric geometries that represent sacrificial liners. The PorePress code is essentially a 1- and 2-dimensional differential equation solver for mixed, unstructured geometries. Specifically, the code is used for solving a coupled form of the Ideal Gas Law, Conservation of Mass, and Conservation of Momentum Equations, which describe the flow and resulting pressures within liner geometries. The code centers around using Taylor Series expansions to approximate derivatives needed to solve the appropriate differential equations. The derivative approximation process used in PorePress is grid transparent, meaning the same method can be used for any combination of quadrilateral (4-sided) or triangular (3-sided) elements in a mesh, without any changes to the code.
Stability issues arise in both the 1- and 2-D PorePress solution processes, as a result of the non-linear nature of the coupled equations, high spatial gradients, and large variations in material properties. In the 1-D case stabilization techniques such as: upwinding, dynamic differencing, under-relaxation, and preconditioning are applied. Meanwhile, in the 2-D case, stabilization techniques such as: inverse weighting and QR factorization of the coefficient matrix, under-relaxation, and preconditioning are applied.
The steady state and transient solution processes for both the 1- and 2-D pore pressure solution processes used in PorePress are covered in this thesis, as well as discussion of the resulting pressure distributions. Certain sacrificial liner design considerations that arise as a result of PorePress models for sample liner burns are also covered.Master of Science
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Salleh, Sharuddin bin Md. "Cyclic loading of carbonate sand : the behaviour of carbonate and silica sands under monotonic and various types of cyclic triaxial loading of isotropically consolidated undrained samples". Thesis, University of Bradford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338750.
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