Coal rock cleat compression coefficient test device, determination method and system

Abstract

The invention provides a coal and rock cleat compression coefficient test device, determination method and system, the device includes: a pulse generator, an upstream gas chamber, a core holder, a temperature controller, a temperature control box, a downstream gas chamber, helium tank and advection pump; the outlet of the pulse generator is connected to the inlet of the core holder through the upstream gas chamber, the outlet of one end of the downstream gas chamber is connected to the outlet of the core holder, and the outlet of the other end of the downstream gas chamber is connected to the outlet shut-off valve, The advection pump is connected to the outer chamber of the core holder through a high-pressure pipeline, and the outlet of the pulse generator is also connected to the outlet of the other end of the downstream gas chamber through a pipeline. The core holder is set in the temperature control box, and the temperature controller and temperature control The box is connected to control the temperature of the temperature-controlled box, and the helium tank is connected to the inlet of the pulse generator through a helium shut-off valve. The invention realizes the test of coal rock cleat compression coefficient under different conditions, reduces the experimental test time, establishes an accurate calculation model of cleat compression coefficient, and improves the test accuracy.

Description

technical field [0001] The invention relates to the technical field of coal-rock experimental analysis in the development of coal-bed methane, in particular to a coal-rock cleat compression coefficient testing device, determination method and system. Background technique [0002] With the upgrading of the domestic energy structure and the improvement of environmental protection requirements, the proportion of natural gas consumption in energy consumption is increasing year by year. my country is a country with abundant coal resources but relatively short natural gas resources. The utilization rate of renewable resources can also reduce the rate of safety accidents such as gas leakage and gas explosion in the coal mining process. It is an emerging unconventional energy industry strongly supported by the state. Coal rock is a dual-porous medium with strong stress sensitivity, and the cleat compressibility coefficient is one of the key factors determining the strength of stress ...

AI Technical Summary

Problems solved by technology

[0003] Domestic coalbed methane development has a history of more than ten years. Due to the late start and short development time, the basic theoretical research on coalbed methane exploration and development is relatively weak, especially the research on coal and rock properties is not deep enough. Laboratory experiments are the key to mastering coal and rock properties. The most direct method, but due to the lack of experimental devices and test methods for coal and rock characteristics, it has not played its due guiding role in the production and development of coalbed methane

[0004] In the prior art, there is no testing standard for coal-rock cleat rock coefficient. In the prior art, based on the coal-rock matchstick model, the mathematical relationship between the change law of coal-rock permeability and the cleat compressibility coefficient under different effective confining pressures is established, and the The cleat compressibility coefficient test method has been proposed, but the method in the prior art has the following problems: 1. The cleat width change caused by the elastic deformation of the coal matrix is ​​not considered in the model, and the theoretical model is not accurate enough; 2. The method uses the steady-state method to measure the permeability The rate varies with the effective confining pressure. Since the coal seam permeability of some coal gas fields in China is less than 0.1mD (permeability is generally 2 to 3 orders of magnitude lower than that of foreign countries), the time for the fluid to reach a steady flow state during the experiment is long, and the error of flow measurement 3. It is impossible to study the influence of forward and reverse flow directions on the cleat compression coefficient of coal rock during the experiment. It is difficult to ensure that the experimental conditions are completely consistent by artificially changing the direction of the core, and it is easy to increase the experimental error; 4. It is impossible to simulate the impact of different temperatures on coal rock. Effect of cleat compression factor

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