A coal rock dynamic permeability detection method and device

Abstract

The invention provides a method and a device for detecting the dynamic permeability of coal petrography. The method comprises the following steps: acquiring the original permeability parameters of a coal reservoir, the coal petrography permeability measurement parameters and dynamic permeability parameters; establishing a coal reservoir original permeability model according to the original permeability parameters of the coal reservoir; calculating the coal petrography fracture volume compression coefficient of the coal petrography according to the coal and rock permeability measurement parameters and the coal reservoir original permeability model; establishing a coal petrography dynamic permeability prediction model according to the coal petrography dynamic permeability parameters, the coal reservoir original permeability model and the coal a petrography fracture volume compression coefficient; and inputting the coal petrography dynamic permeability parameters of different coal reservoirs under different stress conditions into the coal petrography dynamic permeability prediction model, and generating the coal petrography dynamic permeability. According to the method disclosed by the invention, reliable reservoir physical property parameters are provided for dynamic detection of coal-bed gas well production and parameter optimization of target well sections of a complex structural well, so that the accuracy of detecting the coal petrography dynamic permeability can be improved.

Description

Technical field [0001] The invention relates to coalbed methane exploration and development technology, in particular to a method and device for detecting coal rock dynamic permeability. Background technique [0002] As a replacement energy for conventional oil and gas resources, CBM has become an important part of the world's energy structure. Permeability, as an index to measure the permissible fluid passage capacity of porous media, is one of the key metrics that affects the production of CBM wells and determines the recoverability of CBM reservoirs. On the one hand, when predicting the production of CBM wells, it is necessary to determine and predict the migration speed of CBM, and the flow rate of the fluid largely depends on the permeability of the reservoir; on the other hand, the permeability is to determine the CBM reservoir. The most commonly used parameters for mining economic value. However, because the texture of coal is fragile, gas adsorption and desorption have ...

AI Technical Summary

Problems solved by technology

However, because the texture of coal rock is fragile, gas adsorption and desorption have a great influence on the permeability of the reservoir, and the permeability of the coal reservoir is the most difficult parameter to measure.

[0003] At present, the existing permeability prediction methods are not perfect, and there are many deficiencies. For example, the existing permeability models based on elastic mechanics set the fracture volume compression coefficient as a fixed value to simplify the calculation process, which affects the permeability prediction. The accuracy of the permeability model established based on the experiment is mostly simple data regression, and the units and dimensions of the two sides of the obtained prediction formula are different, so this permeability model is only numerically equal, and the physical meaning is not clear

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