A coalbed methane adsorption and desorption experimental method and equipment for simultaneous injection of gas and water

Abstract

The invention provides a gas-water co-injection coalbed methane adsorption and desorption experiment method and gas-water co-injection coalbed methane adsorption and desorption experiment equipment. The equipment comprises a methane storage tank (1), a water vapor generator (2), a first container R1 (3), a second container R2 (4), a third container R3 (5), and a fourth container R4 (6) for loading an experiment coal sample, wherein the first container R1 is controllably communicated to the outside through a pipeline and the first gas inlet (7) of the other end of the pipeline, the second container R2 is controllably communicated to the outside through a pipeline and the second gas inlet (8) of the other end of the pipeline, the first container R1 and the second container R2 are respectively and controllably communicated to the third container R3 through pipelines, the third container R3 is controllably communicated to the fourth container R4 through a pipeline, the water vapor generator can be communicated to the second gas inlet so as to communicate to the second container R2, and the methane storage tank can be communicated through the first gas inlet so as to communicate to the first container R1.

Description

technical field [0001] The invention relates to the field of coalbed methane adsorption and desorption, in particular to a coalbed methane adsorption and desorption experimental method and equipment for simultaneous injection of gas and water. Background technique [0002] At present, the high-pressure volumetric isothermal adsorption experiment method of coal is commonly used at home and abroad, that is, a coal sample of a certain particle size is placed in a sealed container, and the volume of the experimental gas such as methane adsorbed when the adsorption equilibrium is reached under different pressure conditions is measured. According to the Langmuir monolayer adsorption theory, the Langmuir volume (V L ), Langmuir pressure (P L ) and adsorption isotherms. This method is now commonly used. [0003] The principle of the high-pressure volumetric method is: put the processed dry coal sample into the adsorption tank, degas it under high-temperature vacuum, fill the free...

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Problems solved by technology

[0007] The disadvantages of this method are: the original formation conditions cannot be restored, and the experimental environment is quite different from the original reservoir conditions where water exists in the coal matrix pores. The adsorption and desorption theory based on this method does not consider the role of water in the matrix.

[0016] The disadvantage of this method is that although the isothermal adsorption test results of equilibrium water coal samples are closer to in-situ formation conditions than dry coal samples, strictly speaking, there is free water in coal seams under reservoir conditions, and equilibrium water treatment is only equivalent to restoring Decomposed water, combined water, adsorbed water, and free water cannot be recovered under this condition

[0018] The advantages and disadvantages of this method are: this method takes into account the influence of water on the adsorption process of coal bed methane, but when water is injected and then filled with methane for adsorption, since the surface of coal particles is covered by a water film, methane can only be adsorbed on the water film , the adsorption amount obtained in the experiment is smaller than the actual situation

[0021] The advantages and disadvantages of this method are: this method takes into account the influence of water on the desorption process of coalbed methane, but when desorption is performed after water injection, due to the blocking effect of water on methane molecules, the experimental desorption data is smaller than the real situation

[0022] Relevant research results show that the wetting sequence has an impact on adsorption and desorption, but the existing experimental wetting does not take into account the fact that gas and water are generated simultaneously in the process of coalbed methane accumulation.

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