Device for Simultaneous Measurement of Gas Injection Coal Expansion and Permeability under Triaxial Stress Conditions

Abstract

The invention discloses a device for simultaneously measuring expansion and permeability rate of gas injected into a coal rock under a tri-axial stress condition. The device comprises a gas injection system (1), a confining pressure system (2), an axial pressure loading machine (25), a permeability measuring system (3) and a data acquisition system (4), wherein the gas outlet port of the gas injection system (1) is connected with the gas inlet port of the confining pressure system (2) through a high pressure gas inlet pipe (43); the axial pressure loading machine (25) is arranged at the external part of the confining pressure system (2); the permeability measuring system (3) is connected with the gas outlet port of the confining pressure system (2) through a high pressure gas pipe; and the data acquisition system (4) is connected with the confining pressure system (2) through a data line with a sensor. According to the device provided by the invention, the problem of measuring coal-body deformations and permeability variations of different adsorption gases at different temperatures and different pressures is effectively solved; in addition, the permeability and coal-body change laws caused by a gas injection displacement in the process of developing coal bed gases are effectively simulated so that the production practice is beneficial to be further guided.

Description

technical field [0001] The invention belongs to the technical field of air pressure testing, and in particular relates to a device for simultaneously measuring expansion and permeability of gas injected into coal and rock under triaxial stress conditions. Background technique [0002] Coal bed methane is a new type of clean and clean energy. From the perspective of coal mine safety and energy utilization, my country's coal departments, petroleum departments, geological and mining departments, local governments, and domestic and foreign CBM companies have successively constructed nearly 5,000 CBM wells in 42 coal-bearing areas in China (by the end of 2010). However, except for a few areas such as the southeast of Qinshui Basin in Shanxi, Tiefa in Liaoning, and Hedong Coalfield in Shanxi, which have achieved partial commercial development, the test results of CBM development in most areas are not satisfactory. [0003] Whether coalbed methane can be produced and the amount of...

AI Technical Summary

Problems solved by technology

A large number of studies done by the predecessors generally only studied the changes in the physical parameters of coalbed methane before mining, and could not give quantitative expressions on the gas adsorption, desorption of coal rocks, swelling phenomena and the resulting permeability.

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