| With the increasing mining depth of Lvjiatuo mine in Kailuan mine,the local abnormal problems of deep gas need to be solved.Through geological investigation,basic data and gas monitoring data collection of Lvjiatuo mine,the research area is divided into shallow mine and deep mine according to the actual situation of mine.Based on this,the characteristics of deep and shallow gas content and gas emission in the mined area are compared and analyzed.At the same time,isothermal adsorption,liquid nitrogen adsorption,high-pressure mercury injection,nano CT and other experimental means were used to test the collected coal samples.The pore fracture and adsorption characteristics of main coal seams were studied,and the influence of coal reservoir characteristics on coal seam gas occurrence in the study area was clarified.On this basis,the main control factors of deep gas accumulation in the mine are deeply analyzed,and the gas geological law of Lvjiatuo mine is clarified.Based on PSO-BP and the prediction method of different sources,the deep gas content and gas emission in the non mined area of Lvjiatuo mine are predicted respectively The results show that:In the mine depth of-690m,the gas emission characteristics of the study area have obvious changes,which is regarded as the boundary between deep and shallow.the shallow gas content span of the mined area is large,with an average of 2?3 m~3/t,and the deep gas content is stable,mainly distributed in 3?4 m~3/t.the gas emission of the deep working face of the mined area is higher than that of the shallow working face on the whole.Coal rank of each coal seam is coking coal,and the macro and micro fractures are relatively developed.The pore morphology and pore size characteristics show that the pore connectivity of all coal seams is relatively good,and the permeability of coal seam9 is higher,which is conducive to gas escape.The gas adsorption capacity of coal seam12 is larger than that of other coal seams,and the gas adsorption capacity of coal seam8 is much smaller than that of other coal seams.Based on the comprehensive analysis of the differences of coal reservoir characteristics,it is considered that the gas content of coal seam 7 and 12 is the highest It should be higher than coal seam 8 and 9.The deep gas accumulation is mainly controlled by geological structure,buried depth and surrounding rock characteristics,while the shallow gas accumulation is mainly controlled by geological structure,coal thickness and surrounding rock characteristics.The neural network based on particle swarm optimization is used to predict the gas content in deep coal seam,the average gas content of 8 and 9 coal seams is relatively small and similar,which is 3?4 m~3/t,the average gas content of 12 coal seam is slightly larger,with an average of 4.04 m~3/t,the gas content of coal seam 7 is 5.59 m~3/t,which is higher than that of coal seam.Each coal seam is characterized by low gas content in the middle part of the mine where the structure is simple and the mud content is low,however,the distribution of gas content in coal seam 7 and 8 is mainly controlled by geological structure.The distribution of gas content in coal seam 9 and 12 is not only affected by geological structure,but also controlled by burial depth.The prediction results of gas emission from the working face in the deep non mining area show that the gas emission will gradually increase as the working face further advances to the deep.There are 132 figures,47 tables and 142 references in this paper. |
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