Abstract:The gas permeability of porous medium can be estimated by in-situ tests, which can avoid the defects of laboratory tests, that is, the pore structure of samples must be steady, and the sample size is small. The equation used in-situ tests is derived from 1-dimensional radial gas seepage model, and then the pressure field is given based on analysis of 2-dimensional axially symmetric model. The radial outer boundary rout in the in-situ test equation is the sum of test length and half packer length, and the effective region is the sphere of which the radius is rout. The judgment of whether or not the tests obey the Darcy's law is deduced: the tests are conducted under at least three different fluxes. Taking the flux as abscissa and the difference of pressure square as ordinate, the test points can be curve-fitted as a straight line which crosses origin.
牛冠毅, 曹渊, 王铁良. 原位气体渗透率测量试验公式推导及分析[J]. 岩土工程学报, 2015, 37(9): 1705-1709.
NIU Guan-yi, CAO Yuan, WANG Tie-liang. Deduction of in-situ gas permeability test equation. Chinese J. Geot. Eng., 2015, 37(9): 1705-1709.
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