The Research Of Accumulation Of Coldbed Methand On The Coal Seam Ⅱ In The East Of Fengfeng

Based on the study of the sedimentary characteristics, the coal thickness feature and the coal quality feature, we observe the macrolithotype of the No.2coal on the first, and then the organic maceral composition, reflectance of vitrinite were observed, through oil-immersed reflected light and transmitted light. Organic matter abundance and organic type of the No.2coal in the eastern Fengfeng were quantitatively analyzed, through the Rock Eval, Extraction chloroform bitumen "A", Clan separated and Gas chromatographic of the saturated hydrocarbons experiment. The results:the type of the organic matter of source rock belongs to the Ⅲ1in the study areas, it is a good gas source rock, and it is good potential for gas. In the study areas, the favorable angry regions include Dashucun borefield, Yangdong borefield, Jiulongkou borefield, Cixi exploration area.By using the microscopy, scanning electron microscopy and other to observe the coal reservoir and the exogenous crack, and through the optical scanner observation and section analysis of the lump coal and the pulverized coal, we obtain the fissure and the cleat of the No.2coal bed is more development, the crack is tensile crack, and its connectivity is better, so that is higher permeability. While using the pump instrument, the adsorption isotherm instrument, the seepage and desorption experiment instrument to test the parameter of the coal reservoir properties, and the comparability of the relevant regions. The results show that:the coal reservoir pores save a higher degree, and these are mostly micropores and small holes. The the adsorption ability of the coal reservoir is stong, and there is strong gas storage capacity, while the coal bed is large amout of desorption, short adsorption time, those are conducive to the output of the coalbed methane.On this basis, we make an inquiry on the coalbed methane enrichment controlling factors from many aspects, including structural evolution, stratum burial-thermal evolution history, hydrogeological feature, closed condition, sedimentary environment et.al. And we analyse and summarize the enrichment pattern.According to the analysis of the gas-rich conditions and the influence factors of the output of the coalbed methane, and combined with the evaluation criteria of the coalbed methane preferred area, we use Xiao Fangchun’fuzzy comprehensive evaluation method in the fuzzy math to evaluate the preferred geological mineral districts in the study areas. While according to the evaluation index system of coalbed methane constituencies of Carboniferous-Permian of North China, we find out four optimal regions of the coalbed methane storage areas, including Dashucun borefield and the deep forecast area, Yangdong borefield and the deep forecast area, Jiulongkou borefield and the deep forecast area, Cixi borefield and the deep forecast area. Based on "CBM RESOURCES/RESERVES SPECIFICATION", we use the volume method to estimate the coalbed methane resources. The results show that:the CBM resources is20.878billion cubic meter of the No.2coal seam, and it is4.921billion cubic meter for CBM predictive geological reserves of the-1000m shallow sections, while it is15.957billion cubic meter for the-1000m--2000m strata reserves. The shallow resource abundance is0.30to0.90×108m3/Km2, its belongs to the low abundance coalbed gas field, and to deep speculation, its resource abundance is expected to reach1.00～1.50×108m3/Km2and that can be included in the medium abundance coalbed gas field.