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Study On Pore Of The Low Permeability Coal Seam In Lu’an Mining Area

Posted on:2016-01-24Degree:MasterType:Thesis
Country:ChinaCandidate:J W DuFull Text:PDF
GTID:2271330503455547Subject:Mining engineering
Abstract/Summary:PDF Full Text Request
The coal-bed methane(CBM) resource in Luan mining area is rich, the content of the gas reached 23.33 m3/t and it has the potential to be explored and developed. However, the CBM extraction rate is low because of low permeability of coal reservoir in Luan mining area, so it is difficult to carry out industrial exploitation. In order to improve the efficiency of CBM in exploration and development, the microscopic pore structure characteristics of low permeability coal reservoir were studied in the period of exploratory development and geologic evaluation.In this article, through the data collection in the early stage, we took repressentative coal samples for industry analysis, element analysis, the measurement of coal and rock composition, determination of vitrinite reflectance R0 and the porosity, scanning electron microscopy(SEM), mercury injection experiments and low temperature liquid nitrogen adsorption experiment. In the next, through the classification of the comprehensive experimental data processing and results analysis, we revealed the relationship between the pore structure of the coal and its low permeability, and then explored the basic theory of coal-bed methane exploitation.In Luan mining area, the pore ratio and permeability of the coal in Shanxi 3 # group is better than that of Taiyuan 15 # group; The pore size and permeability in main operting mine as follows: Litsun ore = Gao He > over the ancient city of mine > my ore mine = Chang Village > five Yang ore; The pore distribution of the coal in Luan mining area is uneven, the ratio of the micropores and holes which are in a way of spread mainly is as high as 80.8%, by comparison the mesopores and macropores which give priority to seepage take a lower proportion; The connectivity among the pores of the coal is poor; The fractal calculation results show that the pore structure is complex, the surface is not smooth, and reservoir performance is poor; All the expulsion pressure value is greater than 1 MPa, the minimum nonwetting saturation value is higher than normal value, the maximum mercury injection saturation value is average of 54.45%, and the efficiency of mercury is average 27.58%, the capillary pressure value is bigger, the capillary pressure curve of sorted behaviour show poroperm characteristics of low permeability.Based on the quantitative and qualitative research on coal reservoir pore structure characteristics in Luan mining area, then compare the research results with Fukang mining area in Xinjiang and Shanxi Daning mine which both have good coal reservoir conditions, it is concluded that poor pore permeability is the key factor that results in lower permeability of coal reservoir and less efficient exploitation of CBM, so Luan mining area reservoir renovation is crucial to exploit and develop CBM more productive and efficient.
Keywords/Search Tags:coal-bed methane development, characteristics of pore structure, pore permeability, the pore connectivity, capillary pressure
PDF Full Text Request
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