Method and system for predicting coalbed methane of double-pore coal body

Abstract

The invention belongs to the technical field of testing or analyzing materials by means of measuring chemical or physical properties of the materials, and provides a coal bed gas prediction method and system for a double-pore coal body. The method comprises the steps: arranging gas flow field grid nodes around drill holes in the radial direction of a coal matrix and the radial direction of the coal seam drill holes in a coal body; based on a finite difference method, according to the grid nodes of the gas flow field around the drill hole, discretizing a preset coal body double-pore gas flow model, and obtaining a coal body double-pore gas flow difference model; on the basis of a double-pore gas flow difference model of the coal body, obtaining the fracture internal gas pressure of each fracture flow field grid node in the gas flow field grid nodes around the coal seam drill hole; and according to the gas pressure in the fracture of the fracture flow field grid nodes, based on the Darcy law, calculating the gas flow and / or the gas extraction amount of the drill hole. Therefore, the dynamic change of the extraction quantity of the coal bed gas in a long time period and the accurate prediction of the production quantity of the coal bed gas are realized.

Description

technical field [0001] The present application belongs to the technical field of testing or analyzing materials by means of measuring chemical or physical properties of materials, and relates to a method and system for predicting coalbed methane for double-porosity coal bodies. Background technique [0002] Coalbed methane (commonly known as "gas") is the main associated gas in coal mines, and its main component is methane, which is one of the main causes of underground coal mine accidents. At present, the fundamental control measures to deal with gas disasters are underground drilling to extract gas. Extracting gas from mining coal seams can not only reduce coal mine gas accidents, but also cleanly utilize CBM in coal seams as a natural gas resource, which can be said to kill two birds with one stone. As a strategic resource in the world, how to reasonably predict the dynamic production behavior of coalbed methane and evaluate the output of coalbed methane has always been ...

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Problems solved by technology

[0003] In addition, due to the limitations of some conditions on the site, such as time and economic costs, it is only possible to predict the amount of gas drainage in a short period of time, and it is impossible to directly and accurately predict the late production of coalbed methane several years or even decades later.

In addition, many key parameters are usually included in the design of gas drainage in downhole boreholes (drainage negative pressure, drainage time, borehole diameter, borehole length, borehole spacing, etc.). To optimize the optimal extraction parameters by comparing the gas extraction concentration or extraction volume, it will consume a lot of manpower, time and economic costs

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