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Dual-porosity model for simulating the preferential movement of water and solutes in structured porous media
287A transient flow regimes was measured, and porosity as a function of effective stress. The Wellington shale shows extremely low permeability at elevated effective stress.
and is little affected by degree of nonlinearity of the diffusivity. This robust method is ideal for field applications where soils can display a range of hydraulic properties giving rise to a wide variety of diffusivity behaviour.
935144 Wettability alteration caused by oil-based muds and mud components Yan, J N; Menezes, J L; Sharma, M M SPE Drilling Compl VS, N1, March 1993, P35-44
935149 Transient gas flow around boreholes Chan, D Y C; Hughes, B D; Paterson, L Trans Porous Media VIO, N2, Feb 1993, P137-152
Wettability changes caused by oil based drilling fluids and mud filtrates can lead to reduction of permeabilities measured on cores, which is important when assessing reservoir properties. Wettability and permeability changes of water-wet and fractional-wet cores of Berea sandstone attributable to mud filtrates and whole muds have been investigated in the laboratory. Individual components responsible for significant effects are identified.
In coalbed methane extraction, wells may be shut off and pressure allowed to equilibrate before rapid pressure drop on methane recovery. Borehole spaning has been observed under such conditions. The contribution of fluid (gas) flow to the stress state around the borehole has been examined. The fundamental governing equations are formulated and numerical and approximate analytical solutions for transient flow are obtained.
935145 Horizontal well damage characterization and removal Frick, T P; Economides, M J SPE Prod Facil V8, N1, Feb 1993, P15-22
935150 Dual-porosity model for simulating the preferential movement of water and solutes in structured porous media Gerke, H H; van Genuchten, M T Water Resour Res V29, N2, Feb 1993, P305-319
Conceptual and mathematical description of damage around a horizontal well is analysed. Damage distribution is depicted as a truncated cone, with elliptical bases with shape dependent on vertical to horizontal permeability anisotropy. Analytical expressions are developed for the skin effect which take into account permeability anisotropy. Stimulation methods are discussed and quantified with reference to the shape of the damage distribution. 935146 Global behavior of compressible three-phase flow in heterogeneous porous media Amaziane, B Trans Porous Media VIO, N1, Jan 1993, P43-56 The equivalent behaviour of a compressible three phase flow model in heterogeneous porous media with periodic microstructure is analysed using the homogenisation method. Asymptotic expansions lead to the definition of a global or effective model of an equivalent homogeneous reservoir. Numerical computation of the effective permeability tensor is shown. 935147 Capillary hyperdispersion of wetting liquids in fractal porous media Toledo, P G; Davis, H T; Scriven, L E Trans Porous Media II10, N1, Jan 1993, P81-94 Unexpectedly rapid spreading of water (hyperdispersion) during imbibition into a prewet porous medium has been observed. This is explained in terms of viscous flow along fractal pore walls in thin films, governed by driving forces of capillarity. The forces acting within these films and factors affecting the capillary pressure function are examined. Conditions favouring hyperdispersion are investigated. 935148 Examining the sorptivity for a wide range of diffusivity dependence on water content Lockington, D Trans Porous Media VIO, N1, Jan 1993, P95-101 A new sorptivity formula, derived by the method of weighted residuals, is presented which gives more accurate results for materials with exponentially decreasing diffusivity than do present formulae. It maintains its accuracy for cases of constant diffusivity or diffusivity increasing with water content
A model for variably saturated flow and transport in structured soils or fractured rocks is presented. The system involves two overlying continua, a macropore or fracture pore system and a less permeable matrix system. Water in both continua is assumed mobile. Richards' equation describes water flow, the convection-dispersion equation describes transport. Transport of water and solute between regions is simulated using first order rate equations. The Galerkin finite element method is used to solve the system of nonlinear partial differential equations formulated. The importance of using accurate values of hydraulic conductivity near the surface of rock matrix blocks is demonstrated using sensitivity analysis. 935151 Compound random field models of multiple scale hydraulic conductivity Brannan, J R; Haselow, J S Water Resour Res V29, N2, Feb 1993, P365-372 Accurate simulation of subsurface contaminant transport requires large numbers of hydrological data. Inferred values from interpretation of cores or geophysical logs (soft data) can supplement direct measurements. A practical stochastic method is presented for generating a conductivity field which captures both macroscopic and larger scale heterogeneities whilst retaining the mathematical convenience of the Gaussian random field. Parameters at the macroscopic scale are estimated from laboratory data, those at the megascopic scale from soft information. A variety of hierarchies of scale from grains to facies can be accommodated. 935152 Contaminant spreading in stratified soils with fractal permeability distribution Kemblowski, M W; Wen, J C Water Resour Res V29, N2, Feb 1993, P419-425 Some field data suggest that permeability distribution in the subsurface may have a fractal character with long range correlations. The influence of such permeability distribution on spreading and mixing processes in porous media is examined. Two dimensional transport in a perfectly stratified medium is considered. Transient and asymptotic dispersions are determined. Results indicate a strong correlation between fractal dimension of permeability and the mixing process.
© 1993 Pergamon Press Ltd. Reproduction not permitted
and is little affected by degree of nonlinearity of the diffusivity. This robust method is ideal for field applications where soils can display a range of hydraulic properties giving rise to a wide variety of diffusivity behaviour.
935144 Wettability alteration caused by oil-based muds and mud components Yan, J N; Menezes, J L; Sharma, M M SPE Drilling Compl VS, N1, March 1993, P35-44
935149 Transient gas flow around boreholes Chan, D Y C; Hughes, B D; Paterson, L Trans Porous Media VIO, N2, Feb 1993, P137-152
Wettability changes caused by oil based drilling fluids and mud filtrates can lead to reduction of permeabilities measured on cores, which is important when assessing reservoir properties. Wettability and permeability changes of water-wet and fractional-wet cores of Berea sandstone attributable to mud filtrates and whole muds have been investigated in the laboratory. Individual components responsible for significant effects are identified.
In coalbed methane extraction, wells may be shut off and pressure allowed to equilibrate before rapid pressure drop on methane recovery. Borehole spaning has been observed under such conditions. The contribution of fluid (gas) flow to the stress state around the borehole has been examined. The fundamental governing equations are formulated and numerical and approximate analytical solutions for transient flow are obtained.
935145 Horizontal well damage characterization and removal Frick, T P; Economides, M J SPE Prod Facil V8, N1, Feb 1993, P15-22
935150 Dual-porosity model for simulating the preferential movement of water and solutes in structured porous media Gerke, H H; van Genuchten, M T Water Resour Res V29, N2, Feb 1993, P305-319
Conceptual and mathematical description of damage around a horizontal well is analysed. Damage distribution is depicted as a truncated cone, with elliptical bases with shape dependent on vertical to horizontal permeability anisotropy. Analytical expressions are developed for the skin effect which take into account permeability anisotropy. Stimulation methods are discussed and quantified with reference to the shape of the damage distribution. 935146 Global behavior of compressible three-phase flow in heterogeneous porous media Amaziane, B Trans Porous Media VIO, N1, Jan 1993, P43-56 The equivalent behaviour of a compressible three phase flow model in heterogeneous porous media with periodic microstructure is analysed using the homogenisation method. Asymptotic expansions lead to the definition of a global or effective model of an equivalent homogeneous reservoir. Numerical computation of the effective permeability tensor is shown. 935147 Capillary hyperdispersion of wetting liquids in fractal porous media Toledo, P G; Davis, H T; Scriven, L E Trans Porous Media II10, N1, Jan 1993, P81-94 Unexpectedly rapid spreading of water (hyperdispersion) during imbibition into a prewet porous medium has been observed. This is explained in terms of viscous flow along fractal pore walls in thin films, governed by driving forces of capillarity. The forces acting within these films and factors affecting the capillary pressure function are examined. Conditions favouring hyperdispersion are investigated. 935148 Examining the sorptivity for a wide range of diffusivity dependence on water content Lockington, D Trans Porous Media VIO, N1, Jan 1993, P95-101 A new sorptivity formula, derived by the method of weighted residuals, is presented which gives more accurate results for materials with exponentially decreasing diffusivity than do present formulae. It maintains its accuracy for cases of constant diffusivity or diffusivity increasing with water content
A model for variably saturated flow and transport in structured soils or fractured rocks is presented. The system involves two overlying continua, a macropore or fracture pore system and a less permeable matrix system. Water in both continua is assumed mobile. Richards' equation describes water flow, the convection-dispersion equation describes transport. Transport of water and solute between regions is simulated using first order rate equations. The Galerkin finite element method is used to solve the system of nonlinear partial differential equations formulated. The importance of using accurate values of hydraulic conductivity near the surface of rock matrix blocks is demonstrated using sensitivity analysis. 935151 Compound random field models of multiple scale hydraulic conductivity Brannan, J R; Haselow, J S Water Resour Res V29, N2, Feb 1993, P365-372 Accurate simulation of subsurface contaminant transport requires large numbers of hydrological data. Inferred values from interpretation of cores or geophysical logs (soft data) can supplement direct measurements. A practical stochastic method is presented for generating a conductivity field which captures both macroscopic and larger scale heterogeneities whilst retaining the mathematical convenience of the Gaussian random field. Parameters at the macroscopic scale are estimated from laboratory data, those at the megascopic scale from soft information. A variety of hierarchies of scale from grains to facies can be accommodated. 935152 Contaminant spreading in stratified soils with fractal permeability distribution Kemblowski, M W; Wen, J C Water Resour Res V29, N2, Feb 1993, P419-425 Some field data suggest that permeability distribution in the subsurface may have a fractal character with long range correlations. The influence of such permeability distribution on spreading and mixing processes in porous media is examined. Two dimensional transport in a perfectly stratified medium is considered. Transient and asymptotic dispersions are determined. Results indicate a strong correlation between fractal dimension of permeability and the mixing process.
© 1993 Pergamon Press Ltd. Reproduction not permitted