Topic
Permeability (earth sciences)
About: Permeability (earth sciences) is a research topic. Over the lifetime, 15424 publications have been published within this topic receiving 288535 citations.
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TL;DR: In this article, a new theoretical model for calculating pore volume compressibility and permeability in coals as a function of effective stress and matrix shrinkage, using a single equation is presented.
Abstract: In naturally fractured formations, such as coal, permeability is sensitive to changes in stress or pore pressure (i.e., effective stress). This paper presents a new theoretical model for calculating pore volume compressibility and permeability in coals as a function of effective stress and matrix shrinkage, using a single equation. The equation is appropriate for uniaxial strain conditions, as expected in a reservoir. The model predicts how permeability changes as pressure is decreased (i.e., drawdown). Pore volume compressibility is derived in this theory from fundamental reservoir parameters. It is not constant, as often assumed. Pore volume compressibility is high in coals because porosity is so small. A rebound in permeability can occur at lower drawdown pressures for the highest modulus and matrix shrinkage values. We have also history matched rates from a {open_quotes}boomer{close_quotes} well in the fairway of the San Juan basin using various stress-dependent permeability functions. The best fit stress-permeability function is then compared with the new theory.
387 citations
TL;DR: In this article, the authors utilized an integrated permeability and porosity measurement system to measure the stress dependent porosity of Pliocene to Pleistocene sedimentary rocks from a 2000m borehole.
385 citations
TL;DR: In this paper, the pore-space geometry and the transport processes involving pore fluids are modelled and a statistical description of fluid transport in porous media has been proposed for disordered electronic and magnetic materials.
Abstract: This monograph describes recent progress in modelling the transport properties of sedimentary rock. Statistical descriptions are applied to the pore-space geometry and to the transport processes involving pore fluids. Fractals are used to quantify the pore geometry at length scales shorter than grain size. Percolation theory is applied to fluid flow. The permeability can be expressed in terms of a single effective pore diameter measured from mercury injection capillary pressure. This permeability relation is valid for essentially all porous rock and for a broad class of porous media. Mercury injection provides a powerful caliper of the geometry of a percolation cluster in a pore-space and supplies new information about pore space correlations and dynamics of fluid displacements. The statistical description of fluid transport in porous media has analogues in disordered electronic and magnetic materials. Future work may make substantial use of such analogues to solve more complex problems of direct...
377 citations
TL;DR: In this paper, the authors measured porosity, gas permeability, velocity and attenuation of ultrasonic wave propagation in the thermally-cracked rock of granite in order to assess, respectively, its transport properties and its mechanical strength.
368 citations
TL;DR: In this article, the authors investigated the relationship between the coal matrix shrinkage and the gas flow path in coalbeds and found that the coal volume shrinks by ≈ 0.4% when the gas pressure falls from 6.9 MPa to atmospheric pressure.
366 citations