Method for determining full-pore-diameter pore structure of coal through multi-data fusion

Abstract

The invention belongs to a method for determining the full-pore-diameter pore structure of coal through multi-data fusion. The method comprises steps as follows: 1) the pore structure of the coal is determined with a carbon dioxide adsorption method, a liquid nitrogen adsorption method and a mercury intrusion method respectively; 2) the coal pore structure which has the pore diameter smaller than 2 nm and is determined with the carbon dioxide adsorption method, the coal pore structure which has the pore diameter ranging from 2-100 nm and is determined with the liquid nitrogen adsorption method and the coal pore structure which has the pore diameter larger than 100 nm and is determined with the mercury intrusion method are taken, and accordingly the coal pore structures in the full-pore-diameter range are obtained. The method integrating determination of the full-pore-diameter pore structure of the coal and data fusion is provided, the pore diameter which can be determined with the method ranges from 0.4 nm to 360,000 nm, and the reliability and the repeatability of determination data are greatly improved.

Description

technical field [0001] The invention belongs to the technical field of coal pore structure measurement, and in particular relates to a measurement method for multi-data fusion of coal full-diameter pore structure. Background technique [0002] Coal is a porous medium with a large pore size span and complex structure. Its pore characteristics are the physical basis of coal gas adsorption, desorption, diffusion, seepage and coal strength. Coal specific surface area, pore volume, pore size distribution, fractal dimension and other indicators that characterize coal pore structure are the basic parameters for studying coal seam gas adsorption performance, gas adsorption and desorption diffusion mechanism, and seepage characteristics. Risk prediction and important influencing factors of coalbed methane development. The research results on the pore structure at home and abroad show that in the pore system of coal, the smallest pore diameter is only 5 Å (10 -10 m), which is equiva...

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Problems solved by technology

[0004] The domestic published patent document "a coal pore diameter measurement and its pore shape semi-quantitative method" (CN105424580 A), the method uses the combination of mercury porosimetry and liquid nitrogen adsorption method to measure the total pore diameter, which is helpful for improving the coal pore structure. The determination method has a positive promotion effect, which provides a basis for the invention of this method, but there are the following defects: ① The liquid nitrogen adsorption method cannot measure the micropore diameter (P / P 0 About 0.146, the saturated vapor pressure of liquid nitrogen P 0 (111170Pa) close to 1 atmosphere, P / P 0 It is difficult to achieve a lower value, and the vacuum system of the current instrument cannot meet the measurement requirements

When the pressure is greater than 15MPa, since the coal belongs to soft rock, mercury injection is very likely to destroy the pores in the coal, and even create new pores and fissures, resulting in unreliable determination of pore structure parameters

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