| Permian coal seams,dark mudstones and sandstones are widely developed in Panji area,Huainan.Their distribution ranges coincide in the plane,and they appear in the vertical stack.The hydrocarbon generating source rocks are mature,and affected by the structure,the sandstone pores are relatively developed.They have the hydrocarbon generating conditions and reservoir occurrence conditions of the three coal measures(coalbed methane,shale gas and densified sandstone gas),and have the possibility of coupling reservoir formation.In this paper,the deep Permian coal measure strata in Panji,Huainan,are taken as the research object Through geological survey,data collection and experimental testing,the geological background,source rock conditions of three coal.measure gases,migration and storage conditions of three coal measure gases in the study area are investigated,and the mechanism of three coal measure gases coupling reservoir in Panji,Huainan is revealed,The favorable areas of three gas coupling reservoir formation are predicted.The main research results are as follows:Shanxi formation,Xiashihezi Formation and Shangshihezi Formation of Permian are the main coal bearing strata in the study area.The total thickness of coal bearing section is 750m,coal content is 34 layers,and the total thickness of coal seam is 39.22m.Meanwhile,there are rich shale strata in Shanxi Formation and Xiashihezi formation,and the organic carbon content in the dominant area is more than 2.30%,and the organic type is mainly type ? 2 kerogen(sapropel humic type),It has a high potential for hydrocarbon generation of CBM and shale gas.The porosity of coal seams in the study area ranges from 3.071%to 25.094%,with an average of 9.826%.The porosity of most samples is less than 5%,with low porosity.The pore types are parallel plate pore,wedge-shaped pore and fine necked bottle pore,with small fractal dimension and simple pore structure.The permeability ranges from 0.0049 x 10-3-5.72×10-3?m2.Coal and rock have strong adsorption capacity,coalbed methane is self generated and self stored,and a small amount of migration;the porosity of shale is between 0.8667%?4.292%,with an average of 2.21%,and the porosity of all samples is below 5%,with low porosity.Micropores are the main contributor to specific surface area,and the reservoir pore morphology is open,mainly including open parallel wall slit pores.The permeability of shale ranges from 0.00031mD to 0.00091mD,with an average of 0.00046mD.The adsorption capacity of Shanxi shale is stronger than that of Lower Shihezi shale.Shale is both source rock and reservoir rock,and shale gas is also self generated and self stored.The sandstone has poor porosity,low water cut and permeability,poor permeability and water cut of roof and floor,and good trap preservation conditions.The results show that the CBM resource abundance of coal seam 1 and 3 in Shanxi formation is good,and the CBM abundance of the best enrichment area is as high as 0.9× 108m3/km;the thickness of shale in Shanxi Formation varies from 5m to 65m,the TOC content decreases from south to north,the maximum organic carbon content is higher than 2.30%,and the sandstone layer is the thickest in the north and middle of the study area.Based on the repeated vertical characteristics of the three gas reservoirs in coal measures in the study area,three dominant combination types of the three gas reservoirs in coal measures are divided:coalbed methane sandstone gas coalbed methane,shale gas coalbed methane and shale gas sandstone gas coalbed methane,Finally,the favorable areas of three gas coupling reservoir formation in coal measures are predicted,which has practical guidance for the future three gas cooperative exploitation in coal measures.Figure[34]table[29]reference[108]... |
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