Simulation Of Pore And Fracture And Evaluation Of Coal Measure Gas Resources In Various Areas Of Abandoned Working Face

A large number of coal-measure gas resources are still concentrated in the strata of the abandoned coal face.In order to investigate the characteristics of coal/rock of pores and fractures and estimate the amount of coal-measure gas resources in the abandoned coal face,this paper took the 1302 abandoned coal face of yuecheng mine in jincheng mining area as an example,dividing the coal-measure gas storage space scope by numerical simulation,studying coal,mud shale and sandstone pore fracture characteristics of each zone by physical simulation.The pore characteristics of the original and the fractured coal/rock were compared through triaxial mechanical compression and mercury injection experiments.The calculation models of coal-measure gas in each zone were promoted,and the coal-measure gas resources of abandoned coal face 1302 were evaluated.The results show that:(1)the storage space of coal-measure gas in abandoned coal face can be divided into five zones,including the stress concentration zone(?area),the shear fractured zone(?area),the delamination fractured zone(?area),the compaction zone(?area)and the bottom fracture zone(?area);(2)The coal,mud shale,sandstone pore characteristics in each zones are different,especially in?area,where is one of potential coal-measure gas resources development zones in abandoned coal face because of the highest shear fractured degree and reservoir permeability;(3)the initial porosity ratio of coal,mud shale and sandstone is 1:0.66:0.57,and the compressibility ratio of pore fractures in the elastic deformation stage is 1:0.36:0.5.The pore volumes of fractured coal,mud shale and sandstone all decreased to different degrees,and the average porosity attenuation ratio is 1:0.49:0.67,respectively;(4)the coal measure gas resource evaluation process of the abandoned working face is divided into five stages:geological background and mine data investigation,evaluation model selection,zone division and volume calculation,key parameters acquisition,resource evaluation and verification;(5)The"direct addition"calculation model was used to estimate the total amount of coal-measure gas resources in the 1302 abandoned working face of yuecheng coal mine as 1.15×10~6m~3,and the proportion of coal-measure gas resources in areas I,II,III,IV and V was 0.74:0.11:0.03:0.03:0.09.This research results have a effect on the analysis of the characteristics of coal/rock pore and fractures and the evaluation of coal-measure gas resources in abandoned coal face.