Topic
Pore water pressure
About: Pore water pressure is a research topic. Over the lifetime, 11455 publications have been published within this topic receiving 247670 citations. The topic is also known as: pwp.
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TL;DR: In this article, the authors used a pressure transmission technique in specially designed apparatus in which confining pressure, pore pressure, and temperature are independently controlled, and measured anisotropy ratio in gas shale varies from 20% to 31%.
130 citations
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TL;DR: In this article, the authors describe a conceptual model for soils containing large gas bubbles, where the cavities forming the bubble sites are fixed within the soil, so that gas drainage occurs only by the movement of dissolved gas.
Abstract: Offshore site investigations have indicated the presence of undissolved gas bubbles in the soils forming the sea-bed at various locations throughout the world. The gas bubbles are typically much larger than the normal void spaces, so they cannot be considered as occluded bubbles within the pore water which simply change the compressibility of the pore fluid. The effect of these large bubbles on the engineering properties of the soil must be understood if offshore construction is to take place in areas of gas-bearing sediments. This Paper describes a conceptual model for soils containing large gas bubbles. The model consists of a matrix of saturated soil surrounding isolated gas-filled cavities. The cavities forming the bubble sites are fixed within the soil, so that gas drainage occurs only by the movement of dissolved gas. The behaviour of the model is complicated by the processes of localized consolidation and bubble flooding. Des recherches conduites en mer ont indique qu'il y a partout dans le monde d...
130 citations
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TL;DR: In this article, the authors performed coupled Thermo-Hydro-Mechanical (THM) simulations using a robust code called Finite Element for Heat and Mass Transfer (FEHM) for a 3D domain with a single fracture connecting the injection and production wells.
130 citations
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TL;DR: In this paper, the authors measured thermally-induced pore pressure and corresponding concrete temperatures in high-strength concrete (HSC) and normal strength concrete (NSC) to quantify the effects of factors influencing porepressure buildup and potential for explosive spalling in HSC and NSC.
Abstract: Results of an experimental study, which measured thermally-induced pore pressure and corresponding concrete temperatures in high-strength concrete (HSC) and normal strength concrete (NSC), to quantify the effects of factors influencing pore pressure buildup and potential for explosive spalling in HSC and NSC are presented. The specimens are 100 × 200 × 200 mm concrete blocks, heated to a maximum temperature of 600°C (1,112°F) at 5°C/min (41°F/min) and 25°C/min (77°F/min). The complex heat-induced moisture transport process, which varied with specific levels of concrete temperature and significantly influenced the developments of pore pressure and concrete temperature, is explained. Pore pressure developments are shown to be directly related to the moisture transport process and have a significant influence on occurrence of explosive spalling. Effects of water-to-cementitious materials ratios (w/cm), curing conditions, heating rates, and polypropylene (PP) fibers on pore pressure buildup and explosive spalling are quantified and described.
130 citations
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TL;DR: In this paper, ultrasonic velocity and anisotropy measurements of the most mature black shales were used to detect bedding-parallel alignment of the microlayers.
Abstract: Laboratory measurements of ultrasonic velocity and anisotropy in kerogen-rich black shales of varying maturity suggest that extensive, bedding-parallel microcracks exist in situ in most mature source rocks undergoing the major stage of hydrocarbon generation and migration. Given the normal faulting regime with the vertical stress being the maximum principal stress typical of most sedimentary basins, this microcrack alignment cannot be accounted for using simplified fracture mechanics concepts. This subhorizontal microcrack alignment is consistent with (1) a model of local principal stress rotation and deviatoric stress reduction within an overpressured formation undergoing hydrocarbon generation, and with (2) a strong mechanical strength anisotropy of kerogen-rich shales caused by bedding-parallel alignment of kerogen microlayers. Microcracks originate within kerogen or at kerogen-illite interfaces when pore pressure exceeds the bedding-normal total stress by only a few MPa due to the extremely low-fracture toughness of organic matter. P-wave and, especially, S-wave anisotropy of the most mature black shales, measured as a function of confining pressure, indicate the effective closure pressure of these microcracks in the range from 10 to 25 MPa. Estimates of pore pressure cycles in the matrix of the active hydrocarbon-generating/expelling part of the source rock formation show that microcracks can be maintained openmore » over the sequence of these cycles and hence be detectable via high-resolution in-situ sonic/seismic studies.« less
130 citations