Дисертації з теми "Subsurface stress"
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Lejri, Mostfa. "Subsurface stress inversion modeling using linear elasticity : sensitivity analysis and applications." Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS212/document.
Повний текст джерелаToday, one of the main challenges in the oil industry, especially during the exploration phase, is the exploitation of new resources in structurally complex areas such as naturally fractured reservoirs, salt diapirs, mountain ranges, and unconventional reservoirs.We know that the geometry and sliding along active faults modifies the local stress distribution. Knowing the present day perturbed stress field is important for the study of earthquakes, for the planning of the borehole drilling and stability as well as for the prediction of fractures induced by hydro-fracturing and reactivation of natural fractures. In the other side, perturbed paleostress are responsible for the development of (pre-existing) natural fractures. The detection and modeling of the latter, are essential both in the oil industry (migration and trapping of fluids) for a cost efficient recovery of natural reserves.Understanding and quantifying the spatial and temporal development of the stress distribution has a significant economic and environmental impact. The analysis of paleo-constraints was intuitively introduced first by Anderson (1905 & 1942), then in the middle of the last century, Wallace (1951) and Bott (1959) proposed the simple hypothesis that (i) The stress field is homogeneous in space and constant in time, and that (ii) the slip direction is parallel to the traction projected on the fault plane which gives the direction of the shear stress. Many stress inversion methods are based on this hypothesis while recent studies raise doubts as to their compatibility with rock mechanics.In order to investigate the validity of the Wallace and Bott hypothesis, a comparison with vectors of slip generated with numerical models (BEM) is performed. By testing the influence of multiple parameters (geometry, boundary conditions, friction, Poisson’s coefficient , half-space, fault fluid pressure), it is shown that the complex geometry faults subject to specific boundary conditions can yield slip vectors with significant discrepancies with the maximum shear stress resolved on the fault plane. Conversely, the presence of a high sliding friction, allows under certain conditions, to validate the hypothesis of Wallace and Bott.We then focus on the task to compare the results of stress inversions based on the assumption of Wallace and Bott (called classical stress inversion methods) to a geomechanical method. For this, a complex fault geometry is used in a sensitivity analysis (boundary conditions, friction, sampling) to evaluate the uncertainty of the results of the two inversion methods. This analysis is then compared to a case study, Chimney Rock (Utah, USA), showing the advantages and disadvantages of the classical stress inversion methods.One of the main challenges of the oil industry is the exploitation of resource in structurally complex oil fields such as naturally fractured reservoirs. Knowing the heterogeneous paleostress allows to optimize the modeling of these natural fractures. Since slip on faults is hardly observed in petroleum reservoirs, fracture orientation data (joints, faults, stylolites) are naturally taken into account during the inversion of stresses. It is shown, using various field and industry examples, that in such cases the use of mechanical stress inversions is much more appropriate.However, it is sometimes difficult to determine the fracture kinematics observed along wellbores, and very often the studied regions underwent multiple tectonic phases. The final section aims to address the problem of data with unknown kinematic (joints, faults, stylolites ...) and expends the mechanical stress inversion to the separation of tectonic phases
Fang, Xinding Ph D. Massachusetts Institute of Technology. "Geophysical characterization of the effects of fractures and stress on subsurface reservoirs." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/84918.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (pages 259-271).
We study the effect of fractures on reservoir characterization and subsurface rock property measurements using seismic data. Based on the scale of a fracture relative to seismic wavelength, we divide the dissertation into two parts: larger scale fractures and microcracks. In the first part, we study the sensitivity of seismic waves and their time-lapse changes in hydraulic fracturing to the geometrical and mechanical properties of fractures that have dimensions comparable to the seismic wavelength. Through our analysis, we give the general seismic response of a fracture with a linear slip boundary and introduce the fracture sensitivity wave equation for optimal time-lapse survey design. Based on the characteristics of scattering from fractures, we develop an approach to determine the fracture properties using scattered seismic waves. The applicability and accuracy of our method is validated through both numerical simulations and laboratory experiments. Application of our approach to the Emilio Field shows that two orthogonal fracture systems exist and the field data results are consistent with well data. In the second part, we study the effects of microcracks and in situ stress on the formation properties measured from borehole sonic logging. Formation property measurements in a borehole could be biased by the borehole stress concentration, which alters the near wellbore formation properties from their original state. To study this problem, we first develop an iterative approach, which combines a rock physics model and a finite-element method, to calculate the stress-dependent elastic properties of the rock around a borehole when it is subjected to an anisotropic stress loading. The validity of this approach is demonstrated through a laboratory experiment on a Berea sandstone sample. We then use the model obtained from the first step and a finite-difference method to simulate the acoustic response in a borehole. We compare our numerical results with published laboratory acoustic wave measurements of the azimuthal velocity variations along a borehole under uniaxial loading and find very good agreement. Our results show that the variation of P-wave velocity versus azimuth is different from the presumed cosine behavior due to the preference of the wavefield to propagate through a higher velocity region.
by Xinding Fang.
Ph.D.
Rhodes, Rachelle Renee. "Investigating the Functional Response of a Subsurface Biofilm Community to Xenobiotic Stress." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/33412.
Повний текст джерелаMaster of Science
Tse, Man Kit. "Influence of stress states on soil-water characteristics, conjunctive surface-subsurface flow modelling and stability analysis /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202007%20TSE.
Повний текст джерелаChong, Song Hun. "The effect of subsurface mass loss on the response of shallow foundations." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/54271.
Повний текст джерелаWongkamhaeng, Kan. "Effect of chairside surface treatments on biaxial flexural strength and subsurface damage in monolithic zirconia for dental applications." Thesis, University of Iowa, 2016. http://ir.uiowa.edu/etd/3233.
Повний текст джерелаKarimov, Vladimir Rustemovich. "Mathematical modeling of ephemeral gully erosion." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/38230.
Повний текст джерелаDepartment of Biological & Agricultural Engineering
Aleksey Y. Sheshukov
As the world faces an increasing demand for food due to the growing global population and the pernicious effects of land degradation, there is a need to overcome this challenge by using sustainable management practices for agricultural productions. One of the problems, which sustainable agriculture seeks to address, is the loss of topsoil due to soil erosion. Changing weather patterns also contribute to the average annual rainfall across the globe with an excess precipitation, which creates runoff and causes soil erosion. One of the significant yet less studied types of soil erosion is ephemeral gully erosion. Formed by the concentrated overland flow during intensive rainfall events, ephemeral gullies are channels on agricultural fields that can be removed by tillage operations but appear at the same location every year. Even though simplified ephemeral gully models estimate soil losses, they do not account for complicated hydrological and soil erosion processes of channel formations. The purpose of this research work is to investigate sediment sources and develop tools that can predict ephemeral gully erosion more efficiently. To achieve this goal, an experimental study was conducted on an agricultural field in central Kansas by tracking channel development, monitoring soil moisture content, and recording the amount of rainfall. Runoff and sediment loads from contributing catchment and critical and actual shear stresses were estimated by the computer model, and conclusions were made on the effect of saturation dynamics on the erosion processes. Furthermore, a two-dimensional subsurface water flow and soil erosion model was developed with the variable soil erodibility parameters which account for the subsurface fluxes and the effects on the soil detachment process. The model was applied to study the impacts of variable soil erodibility parameters on the erosion process for different soils and various antecedent soil moisture conditions. Also developed to estimate the soil losses at the field scale was an integrated spatially-distributed ephemeral gully model with dynamic time-dependent channel development. The model showed good fit by matching the experimental data. The results from this work can be used to advance the research of soil erosion prediction from concentrated flow channels and ephemeral gullies formed on agricultural fields.
Heaverlo, Nicholas D. "Stress and strain rate estimates associated with penetrative deformation of the Harkless quartzite aureole rocks, Papoose Flat Pluton, California/Using structure contour maps to analyze subsurface 3D fault geometry along segments of the Moine Thrust." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/48425.
Повний текст джерелаMaster of Science
Leach, Jason A. "Stream temperature dynamics following riparian wildfire : effects of stream-subsurface interactions and standing dead trees." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/1411.
Повний текст джерелаHorton, Nial. "Influence of a turbulent stream flow on the subsurface flow through a regular porous matrix." Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources, 2008. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=25938.
Повний текст джерелаPorter, Pamela E. "Comparison between the subsurface environment of brown trout (Salmo trutta) redd and nonredd sites in two North Carolina streams." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/101252.
Повний текст джерелаM.S.
McEwen, Amiana Marie. "Abundance, Distribution, and Geometry of Naturally Occurring Macropores in Stream Banks." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/95948.
Повний текст джерелаMS
House, Abraham. "Examination of the role of macropores and subsurface drainage in the delivery of NO¦3-N to a small first-order agricultural stream in southern Ontario." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ53271.pdf.
Повний текст джерелаOluju, Philemon. "Literature Review of the impacts of riparian vegetation on stream chemistry." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-35206.
Повний текст джерелаPresentation was conducted via Skype
Clark, Tad Dee. "An Analysis of Microstructure and Corrosion Resistance in Underwater Friction Stir Welded 304L Stainless Steel." Diss., BYU ScholarsArchive, 2005. http://contentdm.lib.byu.edu/ETD/image/etd872.pdf.
Повний текст джерелаZhang, Fan. "A NEW PARADIGM OF MODELING WATERSHED WATER QUALITY." Doctoral diss., University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2387.
Повний текст джерелаPh.D.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Civil Engineering
Labarthe, Baptiste. "Quantification des échanges nappe-rivière au sein de l’hydrosystème Seine par modélisation multi-échelle." Thesis, Paris Sciences et Lettres (ComUE), 2016. http://www.theses.fr/2016PSLEM090/document.
Повний текст джерелаGiven the current climate and anthropogenic evolutions, water management becomes one of the greatest challenges of the 21st Century. For that purpose, by identifying hydraulic continuity between surface and subsurface water, the concept of integrated water management can be introduced. In this work this management concept is applied on the Seine basin by quantizing hydrological processes occuring at the nested stream-aquifer interface. The implementatin of the nested interface concept can bedone through multi-scale modeling. This modelling procedure, aimed at embody the local characteristics of the interfaces (such as structural or hydrodynamic heterogeneities) in large scale models. A multi-scale modelling procedures is applied to the regional Seine basin model (70000 km²) in order, to study the hydrodynamic behaviour of the Bassée alluvial plain, and to quantify the stream-aquifer exchanged fluxes at the basin scale. The modelling protocol is initiated with regionals fluxes estimation over Seine hydrosystem. Regional fluxes consistency are assured by a two-step calibration procedure of fully coupled models. Then, the local characteristics of the Bassée alluvial plain, are implemented in the regional model by nested modelling methodology associated with upscaling procedure of hydraulics properties. Finally, the multi-scale modelling procedure lead to quantify distributed stream-aquifer exchanged water fluxes over 83% of the natural river network of the Seine basin, and thus, achieve to answer the integrated water resources management recommandations of the water framework directive
Yen, Pei-chi, and 嚴珮綺. "Estimate the In-situ Stress from Subsurface Geological Data From Hsinchu to Taichung Area,Western Taiwan." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/83769930761425765438.
Повний текст джерела國立中央大學
地球物理研究所
100
This study uses subsurface geological data from wells drilled in the past 40 years to estimate the in-situ stress from Hsinchu to Taichung area. The gradient of vertical stress (Sv) estimated from the formation density log data in Tiehchenshan (TCS) and Chuhuangkeng (CHK) region is about 23 MPa/km. From the repeat formation tests (RFT) collected in Chingtsaohu (CTH), Paoshan (PS), Chinshui (CS), Chuhuangkeng and Tiehchenshan regions, pore pressure (Pp) in sandstone of individual structure can be obtained. Additional background pore pressure values in shale can be estimated from wireline Sonic logs. The top of over-pressure as well as amount of erosional uplift can be inferred based in the plot of pore pressures vs. depth. The Chuhuankeng anticline is highest structure in the Hsinchu and Miaoli area in terms of elevater of the over-pressure zone. Hydraulic fracturing data including leak-off tests (LOTs) and fluid injection in cased and cemented wellbores (mini-fracs) in study area provide a good estimate the minimum horizontal stress (Shmin), which has a gradient about 17~19 MPa/km. The magnitude of maximum horizontal stress (SHmax) was constrained by frictional limits from Anderson’s theory of faulting and by presence of drilling induced tensile fractures. The gradient of the SHmax is about 26~35 MPa/km assuming frictional coefficient (μ) of 0.6. The measured In-situ stress magnitudes indicate a predominantly strike-slip stress regime in Hsinchu and Miaoli area. Applying the methodology of judging borehole breakouts in World Stress Map (WMS), orientations of maximum horizontal stresses were calculated from four-arm caliper tools surveyed in 8 wells. The maximum horizontal stress is predominantly orientated in NW-SE. Detailed SHmax orientation will be affected by surface topography and subsurface structures that wells encountered. The magnitude or the orientation of the in-situ stresses vary at shallow depths. The stress state flips from strike-slip and normal fault, and the SHmax (or Shmin) orientations can also change accordingly.
Rajendrakumar, P. K. "Analysis Of Non-Hertzian Contact Between Rough Surfaces." Thesis, 1997. http://etd.iisc.ernet.in/handle/2005/2149.
Повний текст джерела