The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Stéphane Multon - One of the best experts on this subject based on the ideXlab platform.
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Permeability and damage of partially saturated concrete exposed to elevated temperature
Cement and Concrete Composites, 2020Co-Authors: Hognon Sogbossi, Jérôme Verdier, Stéphane MultonAbstract:This work analyses the impact of elevated temperature on the Permeability and on the damage of concrete according to its saturation degree. The Young Modulus and gas Permeability were measured on samples with different initial saturation degrees that were subjected to thermal loading (80, 150 and 200 °C). These conditions were defined to simulate the hydrothermal loading of nuclear plant concrete in case of accident. To analyse the behaviour of concrete exposed to high temperature, it is necessary to distinguish the effects of water saturation and the impact of damage on Permeability. Experimentations shows that concrete with high saturation degree can be permeable to air after thermal loading, while it was not permeable before the loading. Relations are proposed to link the Permeability Variation to temperature according to the initial saturation degree of the concrete and to evaluate the Permeability Variation from the induced damage.
Erling Siring - One of the best experts on this subject based on the ideXlab platform.
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Vertical and horizontal Permeability Variation within a sandstone reservoir based on minipermeameter measurements
Marine and Petroleum Geology, 1993Co-Authors: Kathryn A. Gibbons, Christian Halvorsen, Erling SiringAbstract:Abstract The drilling and coring through the entire reservoir interval in two wells separated by 570 m presented the opportunity to carry out mini (probe) permeametry measurements on comparable reservoir zones. The reservoir sandstones were deposited in a shallow marine, tidally influenced environment and consist of alternating fine grained micaceous wackes to coarser grained high permeable subarkosic arenites. Statistical analysis of the data had three main objectives: (1) correlation between lithofacies and Permeability; (2) characterization of vertical and horizontal Permeability Variation at the reservoir and reservoir zone scale; and (3) to study relationships between core plug and minipermeameter measurements. Nine lithofacies types are recognized in the cores, ranging from massive homogeneous sandstones through to fine grained, micaceous sandstones with varying degrees of bioturbation. A good correlation is found between minipermeameter measurements and lithofacies. Variograms at the reservoir and reservoir zone scales show similar trends vertically and horizontally (between wells). Variance in core plug data is greater than that for minipermeametry data. Permeability as measured by minipermeametry is significantly higher than core plug measurements, although overall trends are similar in the two data sets. There is generally better agreement between plug and minipermeameter measurements for the highly permeable homogeneous sandstones than for the fine grained micaceous sandstones with relatively low Permeability.
Hognon Sogbossi - One of the best experts on this subject based on the ideXlab platform.
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Permeability and damage of partially saturated concrete exposed to elevated temperature
Cement and Concrete Composites, 2020Co-Authors: Hognon Sogbossi, Jérôme Verdier, Stéphane MultonAbstract:This work analyses the impact of elevated temperature on the Permeability and on the damage of concrete according to its saturation degree. The Young Modulus and gas Permeability were measured on samples with different initial saturation degrees that were subjected to thermal loading (80, 150 and 200 °C). These conditions were defined to simulate the hydrothermal loading of nuclear plant concrete in case of accident. To analyse the behaviour of concrete exposed to high temperature, it is necessary to distinguish the effects of water saturation and the impact of damage on Permeability. Experimentations shows that concrete with high saturation degree can be permeable to air after thermal loading, while it was not permeable before the loading. Relations are proposed to link the Permeability Variation to temperature according to the initial saturation degree of the concrete and to evaluate the Permeability Variation from the induced damage.
Shasha Gao - One of the best experts on this subject based on the ideXlab platform.
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Permeability Variation characteristics of coal after injecting carbon dioxide into a coal seam
International journal of mining science and technology, 2015Co-Authors: Yanbin Wang, Shasha GaoAbstract:Abstract A theoretical basis for the optimization of carbon dioxide injection parameters and the development of the drainage system can be provided by identifying the Permeability change characteristic of coal and rock after injection of carbon dioxide into the coal seam. Sihe, Yuwu, and Changcun mines were used as research sites. Scanning electron microscopy and Permeability instruments were used to measure coal properties such as Permeability and surface structure of the coal samples at different pH values of carbon dioxide solution and over different timescales. The results show that the reaction between minerals in coal and carbonate solution exhibit positive and negative aspects of Permeability-the dissolution reaction between carbonate minerals in coal and acid solution improves the conductivity of coal whilst, on the other hand, the clay minerals in the coal (mainly including montmorillonite, illite and kaolinite) exhibit expansion as a result of ion exchange with the H+ in acid solution, which has a negative effect on the Permeability of the coal. The Permeability of coal samples increased at first and then decreased with immersion time, and when the soaking time is 2–3 months the Permeability of the coal reached a maximum. In general, for coals with permeabilities less than 0.2 mD or greater than 2 mD, the effect on the Permeability is low; when the Permeability of the coal is in the range 0.2–2 mD, the effect on the Permeability is highest. Research into Permeability change characteristics can provide a theoretical basis for carbon dioxide injection under different reservoir Permeability conditions and subsequent drainage.
Ruimin Feng - One of the best experts on this subject based on the ideXlab platform.
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Experimental investigation of in situ stress relaxation on deformation behavior and Permeability Variation of coalbed methane reservoirs during primary depletion
Journal of Natural Gas Science and Engineering, 2018Co-Authors: Ruimin Feng, Satya Harpalani, Suman SaurabhAbstract:Abstract Dynamic evolution of coal deformation and Permeability, induced by changes in in situ stresses with continued depletion in coalbed methane (CBM) reservoirs, has been extensively investigated both experimentally and theoretically. However, the impact of stress-/strain-controlled mechanics on Permeability Variation is somewhat unclear. To examine this behavior, gas flow experiments were conducted under best replicated in situ conditions. Considering that coal anisotropy may lead to changes in deviator stress and coal failure behavior during primary depletion, core flooding experiments were carried out to investigate the anisotropic behavior of coal. Using the experimental results, Mohr's circle of strain was first employed to facilitate the process of analyzing the dynamic deformation behavior of coal. Next, a strain-based failure criterion was developed to analyze the failure tendency of CBM reservoirs in order to explain the sudden increase in Permeability observed during experimental work. The results show that the abrupt increase in Permeability can be attributed to shear failure of coal due to increased deviator stress resulting from in situ stress redistribution after significant depletion. This study sheds light on the influence of stress relaxation on coal deformation behavior, failure tendency and Permeability evolution, with practical implication for gas flow modeling of CBM reservoirs.
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Laboratory measurement of stress-dependent coal Permeability using pulse-decay technique and flow modeling with gas depletion
Fuel, 2016Co-Authors: Ruimin Feng, Satya Harpalani, Rohit PandeyAbstract:Abstract A laboratory-scale coal Permeability measurement study using the pressure pulse decay method was carried out to establish the Permeability Variation trend impacted by the combined effects of effective stresses and coal matrix shrinkage associated with gas depletion under uniaxial strain condition for San Juan basin coal. The experimental results showed that increased effective horizontal stress negatively impacts Permeability enhancement. Furthermore, effective horizontal stress dominates the Permeability Variation. Finally, the rate of Permeability increase accelerates dramatically at low pressures as a result of decrease in effective horizontal stress due to the matrix shrinkage effect. The established pressure-dependent-Permeability (PdK) was compared with modeled results using two models, Harpalani and Chen and Shi and Durucan, both based on Variations in effective horizontal stress. The match with the results obtained using the Harpalani and Chen model was perfect when appropriate initial cleat porosity and matrix shrinkage strain parameters were used. However, given the analytical conditions presented, the agreement between experimental and modeled results using the Shi and Durucan model was poor. After reviewing the fundamental principles behind model development, a modification was made, based on geo-mechanical principles. The measured Permeability Variation matched well with the results predicted by the modified model when appropriate cleat compressibility values were used. Basically, the revised model increases the effect of matrix shrinkage on Permeability changes with continued depletion. The modeled results showed a Permeability trend consistent with the experimental result although the Permeability of coal was overestimated at low pressures.