鄂尔多斯盆地东缘煤系页岩气储层特征评价

Assessment of Coal Measures Shale Gas Reservoir Features in Ordos Basin Eastern Margin

以鄂尔多斯盆地东缘石炭-二叠系富有机质泥页岩为研究对象,基于大量的钻孔泥页岩采样和分析测试,分区分层段对页岩气储层特征进行了评价。结果表明:鄂尔多斯盆地东缘石炭-二叠系富有机质暗色泥页岩广泛发育,泥页岩总厚度为90m左右,有机碳含量为1. 5%~5%,为Ⅲ型高成熟-过成熟状态的有机质;泥页岩脆性指数平均为31. 7%~42. 6%;储层具有微小的孔隙结构,平均孔径12. 2nm,平均比表面积6. 8m^2/g,平均孔体积0. 017cm^3/g,孔隙度为0. 82%~5. 91%;多数泥页岩样品的兰氏体积小于1m^3/t;总体而言,研究区页岩气源岩和储层物性条件良好,但含气量偏低。

Taking the Permo-Carboniferous organic matter rich argillutite in the Ordos Basin eastern margin as the subject investigated,based on substantial borehole argillutite sampling,analysis and testing carried out zonal and layered assessment for shale gas and reservoir features. The result has shown that Permo-Carboniferous organic matter rich dark argillutite is widely developed in the area with total thickness about 90 m. The argillutite organic carbon content is generally between 1. 5% ~ 5%,belongs to category Ⅲ high-over mature organic matter;argillutite brittleness index average is 31. 7% ~ 42. 6%. The reservoir has minute pore structures with average aperture 12. 2 nm,average specific surface area 6. 8 m^2/g,average pore volume 0. 017 m^3/g,porosity 0. 82% ~ 5. 91%;Langmuir’s volume of most argillutite samples is less than 1 m^3/t. On the whole,shale gas source rock and reservoir physical property conditions in the study area are good,but gas content on the low side.