scholarly journals Experimental studies and model analysis of noble gas fractionation in low-permeability porous media

2017 ◽  
Vol 205 ◽  
pp. 149-167 ◽  
Author(s):  
Xin Ding ◽  
B. Mack Kennedy ◽  
Sergi Molins ◽  
Timothy Kneafsey ◽  
William C. Evans
2016 ◽  
Vol 15 (2) ◽  
pp. vzj2015.06.0095 ◽  
Author(s):  
Xin Ding ◽  
B. Mack Kennedy ◽  
William C. Evans ◽  
David A. Stonestrom

2020 ◽  
Vol 59 (9) ◽  
pp. 091003
Author(s):  
Takashi Fujita ◽  
Shigeta Sakai ◽  
Yuma Ikeda ◽  
Atsushi A. Yamaguchi ◽  
Susumu Kusanagi ◽  
...  

2021 ◽  
Author(s):  
Imane Guetni ◽  
Claire Marlière ◽  
David Rousseau

Abstract Application of chemical enhanced oil recovery (C-EOR) processes to low-permeability sandstone reservoirs (in the 10-100 mD range) can be very challenging as strong retention and difficult in-depth propagation of polymer and surfactant can occur. Transport properties of C-EOR chemicals are particularly related to porous media mineralogy (clay content). The present experimental study aimed at identifying base mechanisms and providing general recommendations to design economically viable C-EOR injection strategies in low permeability clayey reservoirs. Polymer and surfactant injection corefloods were conducted using granular packs (quartz and clay mixtures) with similar petrophysical characteristics (permeability 70-130 mD) but having various mineralogical compositions (pure quartz sand, sand with 8 wt-% kaolinite and sand with 8 wt-% smectite). The granular packs were carefully characterized in terms of structure (SEM) and specific surface area (BET). The main observables from the coreflood tests were the resistance and residual resistance factors generated during the chemical injections, the irreversible polymer retention and the surfactant retention in various injection scenarios (polymer alone, surfactant alone, polymer and surfactant). A first, the impact of the clay contents on the retention of polymer and surfactant considered independently was examined. Coreflood results have shown that retention per unit mass of rock strongly increased in presence of both kaolinite and smectite, but not in the same way for both chemicals. For polymer, retention was about twice higher with kaolinite than with smectite, despite the fact that the measured specific surface area of the kaolinite was about 5 times less than that of the smectite. Conversely, for surfactant, retention was much higher with smectite than with kaolinite. Secondly, the impact of the presence of surfactant on the polymer in-depth propagation and retention was investigated in pure quartz and kaolinite-bearing porous media. In both mineralogies, the resistance factor quickly stabilized when polymer was injected alone whereas injection of larger solution volumes was required to reach stabilization when surfactant was present. In pure quartz, polymer retention was shown, surprisingly, to be one order of magnitude higher in presence of surfactant whereas with kaolinite, surfactant did not impact polymer retention. The results can be interpreted by considering adsorption-governed retention. The mechanistic pictures being that (a) large polymer macromolecules are not able to penetrate the porosity of smectite aggregates, whereas surfactant molecules can, and (b) that surfactant and polymer mixed adsorbed layers can be formed on surfaces with limited affinity for polymer. Overall, this study shows that C-EOR can be applied in low permeability reservoirs but that successful injection strategies will strongly depend on mineralogy.


Author(s):  
Gennadiy Sandrakov ◽  
Andrii Hulianytskyi ◽  
Vladimir Semenov

Modeling of dynamic processes of diffusion and filtration of liquids in porous media are discussed. The media are formed by a large number of blocks with low permeability, and separated by a connected system of faults with high permeability. The modeling is based on solving initial boundary value problems for parabolic equations of diffusion and filtration in porous media. The structure of the media leads to the dependence of the equations on a small parameter. Assertions on the solvability and regularity of such problems and the corresponding homogenized convolution problems are considered. The statements are actual for the numerical solution of this problem with guaranteed accuracy that is necessary to model the considered processes.


1999 ◽  
Author(s):  
Gerard A. Ateshian ◽  
Michael A. Soltz

Abstract Experimental studies have demonstrated that the moduli of articular cartilage in compression are one to two orders of magnitude smaller than in tension. However, only a few analyses of cartilage mechanics have been performed which account for this tension-compression nonlinearity (Soulhat et al., 1998; Ateshian and Soltz, 1999a,b). In order to understand the state of stress under loading conditions which simulate the physiologic environment of diarthrodial joints, and the possible implications for tissue failure and the pathomechanics of osteoarthritis, it is important to determine whether the tension-compression nonlinearity of cartilage significantly affects our current understanding of its response in contact mechanics. Most analyses of cartilage contact have employed linear isotropic or transversely isotropic models for cartilage, either within the context of elasticity theory or porous media theories. In this study, we present a finite element solution for the contact of a rigid spherical impermeable sphere against a cartilage layer supported on a rigid impermeable subchondral bone foundation, where cartilage is modeled using our recently proposed biphasic conewise linear elasticity model (Ateshian and Soltz, 1999a,b). A comparison is also provided with the more frequently used linear isotropic biphasic model, under similar conditions.


2019 ◽  
Author(s):  
Imane Guetni ◽  
Claire Marliere ◽  
David Rousseau ◽  
Isabelle Bihannic ◽  
Manuel Pelletier ◽  
...  

Symmetry ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 364 ◽  
Author(s):  
Huimin Wang ◽  
Jianguo Wang ◽  
Xiaolin Wang ◽  
Andrew Chan

Low-permeability porous medium usually has asymmetric distributions of pore sizes and pore-throat tortuosity, thus has a non-linear flow behavior with an initial pressure gradient observed in experiments. A threshold pressure gradient (TPG) has been proposed as a crucial parameter to describe this non-linear flow behavior. However, the determination of this TPG is still unclear. This study provides multi-scale insights on the TPG in low-permeability porous media. First, a semi-empirical formula of TPG was proposed based on a macroscopic relationship with permeability, water saturation, and pore pressure, and verified by three sets of experimental data. Second, a fractal model of capillary tubes was developed to link this TPG formula with structural parameters of porous media (pore-size distribution fractal dimension and tortuosity fractal dimension), residual water saturation, and capillary pressure. The effect of pore structure complexity on the TPG is explicitly derived. It is found that the effects of water saturation and pore pressure on the TPG follow an exponential function and the TPG is a linear function of yield stress. These effects are also spatially asymmetric. Complex pore structures significantly affect the TPG only in the range of low porosity, but water saturation and yield stress have effects on a wider range of porosity. These results are meaningful to the understanding of non-linear flow mechanism in low-permeability reservoirs.


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