Open AccessEffective pressure law for permeability of E‐bei sandstones
Author(s) -
Li M.,
Bernabé Y.,
Xiao W.I.,
Chen Z.Y.,
Liu Z.Q.
Publication year - 2009
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2009jb006373
Subject(s) - permeability (electromagnetism) , overburden pressure , porosity , geology , fluid pressure , mineralogy , characterisation of pore space in soil , soil science , geotechnical engineering , mechanics , chemistry , physics , biochemistry , membrane
Laboratory experiments were conducted to determine the effective pressure law for permeability of tight sandstone rocks from the E‐bei gas reservoir, China. The permeability k of five core samples was measured while cycling the confining pressure p c and fluid pressure p f . The permeability data were analyzed using the response‐surface method, a statistical model‐building approach yielding a representation of k in ( p c , p f ) space that can be used to determine the effective pressure law, i.e., p eff = p c − κ p f . The results show that the coefficient κ of the effective pressure law for permeability varies with confining pressure and fluid pressure as well as with the loading or unloading cycles (i.e., hysteresis effect). Moreover, κ took very small values in some of the samples, even possibly lower than the value of porosity, in contradiction with a well‐accepted theoretical model. We also reanalyzed a previously published permeability data set on fissured crystalline rocks and found again that the κ varies with p c but did not observe κ values lower than 0.4, a value much larger than porosity. Analysis of the dependence of permeability on effective pressure suggests that the occurrence of low κ values may be linked to the high‐pressure sensitivity of E‐bei sandstones.