沁水盆地阳泉区块上古生界煤系页岩气储层特征

页岩储层特征是进行页岩气储集能力评价的基础内容。为探究高演化阶段煤系页岩气储层性质和优选有利储层，运用岩石热解、X射线衍射、扫描电子显微镜、高压压汞、低温N₂和CO₂气体吸附多种实验方法，对沁水盆地阳泉区块上古生界煤系页岩岩心样品进行储层特征研究。结果表明：沁水盆地阳泉区块上古生界煤系页岩，有机碳含量较高(TOC平均为4.9%)，处于过成熟阶段(R_ran平均为2.32%)，黏土矿物质量分数较高(平均为50.0%)，具有低孔低渗的特征(孔隙率平均为6.61%，渗透率平均为0.006 3×10^–3μm²)，孔隙类型以粒间孔、粒内孔和微裂缝为主，微米–纳米级孔隙为页岩气的赋存提供了储集空间；孔隙总孔容为0.025 5~0.051 7 mL/g，平均0.038 9 mL/g，总比表面积为12.64~40.98 m²/g，平均28.43 m²/g，微孔(<2 nm)、介孔(2~50 nm)的孔容与比表面积呈良好的正相关性，宏孔(>50 nm)孔容与比表面积则相关性不明显，表明微孔和介孔是阳泉区块煤系页岩气储集的主要载体。总体来说，阳泉区块上古生界煤系页岩具有较好的页岩气储集性能，但页岩储层可压裂性较差，影响页岩气的开发。

Characteristics of shale gas reservoir in Upper Paleozoic coal measures in Yangquan Block,Qinshui Basin

Shale reservoir characteristics are the basic content of shale gas storage capacity evaluation. In order to explore the properties of high-evolved coal-measures shale gas reservoirs and optimize favorable reservoirs, various experimental methods of rock pyrolysis, X-ray diffraction, scanning electron microscopy, high-pressure mercury intrusion, low-temperature N₂ and CO₂ gas adsorption were applied to the Qinshui Basin. Reservoir characteristics were studied with core samples of coal-measure shale core from the Upper Paleozoic in Yangquan Block. The results show that the Upper Paleozoic coal-measures shale in Yangquan Block of the Qinshui Basin has a high content of organic carbon(average TOC is 4.9%), is in an over-mature stage(average R_ran is 2.32%), and has a high content of clay minerals(average is 50.0%), with the characteristics of low porosity and low permeability(average porosity of 6.61%, average permeability of 0.006 3×10–3 μm2). The pore types are mainly intergranular pores, intragranular pores and microcracks, and micro-nano-scale pores provide the storage space for the occurrence of shale gas; the total pore volume of pores is 0.025 5-0.051 7 mL/g, the average is 0.038 9 mL/g, the total specific surface area is 12.64-40.98 m2/g, the average is 28.43 m2/g, the pore volume of the micropores(< 2 nm), and the mesopores(2-50 nm) has a good positive correlation with the specific surface area, while the pore volume of macropores(>50 nm) has no obvious correlation with the specific surface area, indicating that the micropores and the mesopores are Yangquan blocks. The main carrier of coal-measure shale gas accumulation. In general, the Upper Paleozoic coal-measure shale in the Yangquan Block has good shale gas storage performance, but the shale reservoir has poor fracturing properties, which will affect the development of shale gas.