scholarly journals Influence of Shear Displacement on Fluid Flow and Solute Transport in a 3D Rough Fracture

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 4) ◽  
Author(s):  
Zhi Dou ◽  
Songxuan Tang ◽  
Xueyi Zhang ◽  
Richeng Liu ◽  
Chao Zhuang ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Solute Transport ◽  
Fractured Rocks ◽  
Dispersion Coefficient ◽  
Mechanistic Model ◽  
Exchange Process ◽  
Shear Displacement ◽  
Rough Fracture ◽  
Advection Diffusion Equation ◽  
Early Arrival

Abstract Fractured rocks in the subsurface are ubiquitous, and the dynamics of mass transfer in fractured rocks plays an important role in understanding the problem in engineering geology and environmental geology. In this study, the influence of shear displacement on fluid flow and solute transport in a 3D rough fracture was investigated. A 3D self-affine rough fracture was generated using the modified successive random addition (SRA) technology, and three sheared fractures with different shear displacements were constructed based on the mechanistic model. A direct numerical model based on the Navier-Stokes equation and the advection-diffusion equation was developed to solve the fluid flow and the solute transport. The results showed that shear displacement had a significant influence not only on the fluid flow but also on the solute transport. A global measure of the spatial variability of the flow velocity showed that the heterogeneity became weaker with decreasing shear displacement. All measured BTCs deviated from the Gaussian profile and exhibited the typical anomalous behaviors, such as the long tail and the early arrival. Although the best-fitted results of the advection-dispersion equation (ADE) model and mobile-immobile model (MIM) were generally consistent with those of the BTCs, the MIM was more capable than the ADE model for characterizing the shear-induced anomalous behavior of the BTCs. It was found that the mass exchange process between the immobile and mobile domains was enhanced in the sheared fractures while the fraction of the advection-dominant mobile domain decreased as the shear displacement increased. Furthermore, the deviation of the Taylor dispersion coefficient from the fitted dispersion coefficient by the ADE model and MIM in the sheared fractures was confirmed due to the influence of shear displacement.

scholarly journals Influence of Chemical Osmosis on Solute Transport and Fluid Velocity in Clay Soils

2020 ◽  
Vol 18 (1) ◽  
pp. 232-238
Author(s):  
Zhihong Zhang ◽  
Gailei Tian ◽  
Lin Han
Keyword(s):  
Solute Transport ◽  
Transport Model ◽  
Fluid Velocity ◽  
Diffusion Mechanism ◽  
Clay Material ◽  
Chemical Osmosis ◽  
Advection Diffusion Equation ◽  
Test Study ◽  
Proposed Model ◽  
Membrane Effect

AbstractSolute transport through the clay liner is a significant process in many waste landfills or unmanaged landfills. At present, researchers mainly focus on the test study about semi-membrane property of clay material, however, the influence of chemical osmosis caused by membrane effect on solute transport and fluid velocity is insufficient. In this investigation, based on the classical advection-diffusion equation, a one-dimensional solute transport model for low-permeable clay material has been proposed, in which the coupled fluid velocity related with hydraulic gradient and concentration gradient is introduced, and the semi-membrane effect is embodied in the diffusion mechanism. The influence of chemical osmosis on fluid velocity and solute transport has been analyzed using COMSOL Multiphysics software. The simulated results show that chemical osmosis has a significant retarded action on fluid velocity and pollutant transport. The proposed model can effectively reveal the change in process of coupled fluid velocity under dual gradient and solute transport, which can provide a theoretical guidance for similar fluid movement in engineering.

Experimental Study of Natural Ions and Rock Interactions for Seawater Breakthrough Percentage Monitoring during Offshore Seawater Flooding

SPE Journal ◽  
2021 ◽  
pp. 1-21
Author(s):  
Yanqing Wang ◽  
Xiang Li ◽  
Jun Lu
Keyword(s):  
Porous Media ◽  
Fluid Flow ◽  
Barium Sulfate ◽  
Large Deviation ◽  
Exchange Process ◽  
Reaction Model ◽  
Sodium Content ◽  
Flow In Porous Media ◽  
Formation Water ◽  
The Impact

Summary Seawater breakthrough percentage monitoring is critical for offshore oil reservoirs because seawater fraction is an important parameter for estimating the severity of many flow assurance issues caused by seawater injection and further developing effective strategies to mitigate the impact of those issues on production. The validation of using natural ions as a tracer to calculate the seawater fraction was investigated systematically by studying the natural chemical composition evolution in porous media using coreflood tests and static bottle tests. The applicable range of ions was discussed based on the interaction between ion and rock. The barium sulfate reactive model was improved by integrating interaction between ions and rock as well as fluid flow effect. The results indicate that chloride and sodium interact with rock, but the influence of the interaction can be minimized to a negligible level because of the high concentrations of chloride and sodium. Thus, chloride and sodium can be used as conservative tracers during the seawater flooding process. However, adsorption/desorption may have a large influence on chloride and sodium concentrations under the scenario that both injection water and formation water have low chloride and sodium content. Bromide shows negligible interaction with rock even at low concentrations and can be regarded as being conservative. The application of a barium and sulfate reaction model in coreflood tests does not work as well as in bottle tests because fluid flow in porous media and ion interaction with rock is not taken into account. Although sulfate and barium adsorption on clay is small, it should not be neglected. The barium sulfate reaction model was improved based on the simulation of ion transport in porous media. Cations (magnesium, calcium, and potassium) are involved in the complicated cation-exchange process, which causes large deviation. Therefore, magnesium, calcium, and potassium are not recommended to calculate seawater fraction. Boron, which exists as anions in formation water and is used as a conservative tracer, has significant interactions with core matrix, and using boron in an ion tracking method directly can significantly underestimate the seawater fraction. The results give guidelines on selecting suitable ions as tracers to determine seawater breakthrough percentages under different production scenarios.

Fluid flow and solute transport in a network of channels

1993 ◽  
Vol 14 (3-4) ◽  
pp. 163-192 ◽  
Author(s):  
Luis Moreno ◽  
Ivars Neretnieks
Keyword(s):  
Fluid Flow ◽  
Solute Transport

scholarly journals Numerical Research of Fluid Flow and Solute Transport in Rough Fractures under Different Normal Stress

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Min Wang ◽  
Qifeng Guo ◽  
Pengfei Shan ◽  
Meifeng Cai ◽  
Fenhua Ren ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Shear Flow ◽  
Solute Transport ◽  
Normal Stress ◽  
Three Dimensional ◽  
Dispersive Transport ◽  
Mean Velocity ◽  
Flow Test ◽  
Hydraulic Aperture ◽  
Mechanical Aperture

The effects of roughness and normal stress on hydraulic properties of fractures are significant during the coupled shear flow test. Knowing the laws of fluid flow and solute transport in fractures is essential to ensure the nature and safety of geological projects. Although many experiments and numerical simulations of coupled shear flow test have been conducted, there is still a lack of research on using the full Navier-Stokes (N-S) equation to solve the real flow characteristics of fluid in three-dimensional rough fractures. The main purpose of this paper is to study the influence of roughness and normal stress on the fluid flow and solute transport through fractures under the constant normal stiffness boundary condition. Based on the corrected successive random addition (SRA) algorithm, fracture surfaces with different roughness expressed by the Hurst coefficient ( H ) were generated. By applying a shear displacement of 5 mm, the sheared fracture models with normal stresses of 1 MPa, 3 MPa, and 5 MPa were obtained, respectively. The hydraulic characteristics of three-dimensional fractures were analyzed by solving the full N-S equation. The particle tracking method was employed to obtain the breakthrough curves based on the calculated flow field. The numerical method was verified with experimental results. It has been found that, for the same normal stress, the smaller the fracture H value is (i.e., more tough the fracture is), the larger the mechanical aperture is. The ratio of hydraulic aperture to mechanical aperture ( e h / e m ) decreases with the increasing of normal stress. The smaller the H value, the effect of the normal stress on the ratio e h / e m is more significant. The variation of transmissivity of fractures with the flow rate exhibits similar manner with that of e h / e m . With the normal stress and H value increasing, the mean velocity of particles becomes higher and more particles move to the outlet boundary. The dispersive transport behavior becomes obvious when normal stress is larger.

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