Permeability testing method and device based on radial percolation experiment

Abstract

The invention provides a permeability testing method and device based on a radial percolation experiment and belongs to a permeability testing method and device. A hole is formed in the center of a tested coal sample, gas permeates the central round hole from one side, and the permeability is tested on the basis of the radial percolation experiment and is contrasted with that obtained with a traditional axial percolation testing method. The device comprises a gas source steel cylinder, a gas flow and pressure control system, an axial loading system and a data acquisition and analysis system. Firstly, a cylindrical rock sample with a hole in the center is prepared, then gas confining pressure is applied from one side after the rock sample is arranged on a rock sample placement table, the axial loading mechanism loads axial pressure, and the gas permeates the central round hole in the radial direction from one side and then is exhausted from an exhaust port. The permeability testing method and device have the advantages as follows: the radial percolation capacity of the gas along a sample rock core is tested; methane gas provides confining pressure, which is more realistic for gas extraction research; the problem that experiments fail due to the fact that high-pressure oil is likely to permeate coal under a traditional three-axis stress condition is solved; and stress of the sample can be monitored conveniently.

Description

technical field [0001] The invention relates to a permeability testing method and device, in particular to a permeability testing method and device based on a radial seepage experiment. Background technique [0002] The test of rock or coal seam permeability is not only of great significance for revealing the migration law of underground gas, but also provides an important evaluation standard for evaluating the extractability of coal seam gas and preventing gas disasters. [0003] There are usually experimental methods and field investigation methods for testing the permeability of natural rock formations or coal seams, both of which measure some relevant data and then obtain the permeability according to Darcy's law. [0004] Traditionally, a cylindrical coal sample is generally prepared, and then a sealing film is pasted on the side of the coal sample. High-pressure oil applies confinement pressure to the coal sample. Since only the side of the coal sample is sealed and ga...

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Problems solved by technology

[0004] Traditionally, a cylindrical coal sample is generally prepared, and then a sealing film is pasted on the side of the coal sample. High-pressure oil applies confinement pressure to the coal sample. Since only the side of the coal sample is sealed and gas seepage is required at both ends of the cylindrical sample, the high-pressure oil It is easy to invade the medium and cause the experiment to fail. In addition, because the side strain gauge is squeezed by high-pressure oil, the coal strain test is easy to be inaccurate

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