Device for testing axial loading/unloading gas permeability of coal

Abstract

The invention provides a device for testing the axial loading / unloading gas permeability of coal, comprising a gas pressurizer, a permeability test unit, an axial pressuring and unloading device and a gas collecting device, wherein the permeability test unit consists of a pressure chamber, a bleeder vent plate, a base, the base is provided with a gas inlet channel, a gas outlet channel is arranged at the top part of the pressure chamber and a piston pressure gauge is fixed on the top part; the permeability test device is arranged in the axial pressuring and unloading device which is composed of a lifting table, a triaxial shear instrument, a proving ring arranged at the upper part of the triaxial shear instrument, and the proving ring is provided with a strain dial gauge and a force-measurement dial gauge; the air tube of the gas pressuring device is connected with an air inlet of the base of the axial pressuring and unloading device; and the air header of the gas collecting device is connected with an air outlet at the upper part of the pressure chamber of the axial pressuring and unloading device. The device in the invention is suitable for permeability test for various coal body structures in particular to coal sample construction under the loading and unloading conditions, and has simple structure, convenient operation and good test repeatability.

Description

Technical field [0001] The invention relates to the technical field of testing, in particular to a testing device for gas permeability of coal with coal body structure under axial loading and unloading conditions. Background technique [0002] Permeability is an important technical parameter for the development of coalbed methane. Most of the traditional permeability testing devices require coal samples to be made into regular columnar or block samples. When tested under simulated confining pressure, the mechanical strength of the coal body is relatively high. Requirements. However, it is more difficult to make coal samples of soft and broken tectonic coal into columnar or block samples, and the mechanical strength of tectonic coal is low. It is difficult to use traditional permeability testing devices to simulate different axial pressures and pores of formation conditions in the laboratory. Test coal seam permeability under pressure. Summary of the invention [0003] Technical ...

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Problems solved by technology

However, it is difficult to make columnar or block samples from soft and broken structural coal samples, and the mechanical strength of structural coal is low. It is difficult to simulate different axial pressures and pores of formation conditions in the laboratory using traditional permeability testing devices. Testing coal seam permeability under pressure

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