Method and device for measuring coal rock adsorption gas quantity and permeability

Abstract

The invention discloses a method for measuring coal rock adsorption gas quantity and permeability. The method comprises the following steps of: firstly, sealing a coal sample test piece under the constrained annular strain; putting the sample test piece into an incubator to keep the permeability temperature in the coal sample test piece to be at a preset temperature value; regulating the pressure of gas flowing into and out of the coal sample test piece to ensure that the tested gas flows in the coal sample test piece under the driving of pressure difference so as to guarantee the gas permeability to achieve stable flowing station, and measuring gas flow velocity, in and out pressure value and gas flow; and finally, according to the in and out pressure value of the coal sample test piece and the gas flow numerical value, calculating the permeability and the coal rock adsorption gas quantity. The invention also provides a device for measuring coal rock adsorption gas quantity and permeability. By taking the porous medium percolation theory as a basis, the method and the device for simultaneously measuring the gas adsorption amount and the permeability of the coal sample test piece under the constrained coal sample test piece annular strain conform to the basis of the porous medium seepage experiment, and a foundation for researching the influence on the coal rock permeability by the adsorption action is laid.

Description

technical field [0001] The invention relates to a method and a corresponding device for measuring the permeability of coal rock in a laboratory in the field of coalbed methane development, in particular to a method for measuring gas permeability and gas adsorption of coal rock by using the stable flow of gas in coal rock and device. Background technique [0002] The measurement of coalbed methane permeability is the basis of coalbed methane development, especially for the strong adsorption between coal and coalbed methane, so that the coalbed methane permeability will change during the process of coalbed methane development. In order to better reflect the change characteristics of coal-rock permeability in the process of coalbed methane development. [0003] As early as the 1960s, Chinese scholars have conducted research on the measurement method of coal rock permeability, but only limited to the implementation of annular sealing of coal samples, using heat-shrinkable tubes...

AI Technical Summary

Problems solved by technology

Although this method solves the problem of difficult sealing in the coal sample gas testing experiment, it also makes the coal sample bear excess oil pressure along the direction of internal gas flow from the inlet end, in other words, the coal sample is affected by the oil pressure along the axial direction , showing a compression deformation, which changes the physical and mechanical properties of the coal sample, and also changes the pore-permeability parameters of the coal sample, making the gas permeability test under this experimental condition lose the research significance

At the same time, due to the strong adsorption between coal and gas, the flow of gas in the coal body is extremely complicated. Therefore, when studying the flow law of gas in the coal body, the amount of adsorbed gas in the coal rock should be measured at the same time. The traditional permeability test method cannot Meet the above research needs

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