胶莱盆地陆相页岩气储层微观特征

Reservoir Micro-characteristic of Continental Shale Gas in Jiaolai Basin

基于大量的野外地质调查,运用X射线衍射、压汞、等温吸附试验等实验方法和手段,以胶莱盆地水南组暗色泥页岩为研究对象,分析了陆相页岩气的储层微观特征。研究表明:水南组暗色泥页岩矿物组成主要为黏土矿物、石英、斜长石、方解石和白云石。黏土矿物平均含量32.08%,石英、长石平均含量48.92%,碳酸岩平均含量19.19%,较高的脆性矿物含量有利于后期储层的压裂改造。微观裂缝主要为天然微裂缝及颗粒间裂隙,裂缝宽度0.5~2μm。微观孔隙主要为宏孔和介孔,总孔容0.001~0.02 mL/g,总孔比表面积一般10.0~20.0 cm2/g。水南组暗色泥页岩最大吸附量0.64~0.87 m3/t,平均0.74 m3/t,显示了较好的页岩气吸附能力。

Based on a large number of field geological investigations, using the methods of X ray diffraction, mercury intrusion and isothermal adsorption, taking the dark shale of Shuinan formation in Jiaolai basin as the object, studies reservoir micro-characteristic of continental shale gas. The results show that the dark mud shale minerals of the Shuinan formation are mainly composed of clay minerals,quartz, plagioclase, calcite and dolomite. The average clay mineral content is 32.08%, the average quartz and feldspar content is 48.92%, and the average carbonate content is 19.19%. The higher brittle mineral content is conducive to the fracturing of the reservoir in the later stage. The microcracks are mainly natural microcracks and intergranular cracks, and the width of the cracks is between 0.5 μm and 2 μm. The microscopic pores are mainly macro and mesopore, with the total pore volume ranging from 0.001 mL/g to 0.02 mL/g, and the total pore specific surface area generally ranging from 10.0 cm2/g to 20.0 cm2/g. The maximum adsorption capacity of dark mud shale in the shuinan formation is between0.64 m3/t and 0.87 m3/t, with an average of 0.74 m3/t, indicating a better adsorption capacity of shale gas.