Gao Hai-Tao, Zhu Yan-Ming, Shang Fu-Hua, Chen Chong-Yu
Coalbed Methane Resources and Reservoir Formation Process Key Laboratory of Ministry of Education, China University of Mining & Technology, Xuzhou, Jiangsu 221008, China.
Jiang Su Chinese Coal Geological Engineering Institute Limited Company, Changzhou, Jiangsu 213003, China.
J Nanosci Nanotechnol. 2021 Jan 1;21(1):72-84. doi: 10.1166/jnn.2021.18465.
Shales are widely developed in the strata of the Carboniferous-Permian coal measures in the Qinshui Basin, and these shales have great potential for shale gas exploration. In this paper, the shales of the Taiyuan Formation in the eastern Qinshui Basin are studied. The shales of the Taiyuan Formation in the study area are investigated through field investigation, organic geochemical testing, X-ray diffraction, scanning electron microscopy, high pressure mercury injection, low temperature liquid nitrogen adsorption and PetroMod simulation and through other tests to study the reservoir characteristics, such as organic geochemistry, mineralogy, petrology, pore permeability, and gas burial history. The results show that the shales of the Taiyuan Formation are well developed over the whole area with a thickness of more than 60 m. The average organic matter content is 2.95%, and the kerogen type is type III. The shale maturity (average value is 2.45%) corresponds to the stage of high maturity evolution, indicating that a large amount of shale gas has been generated in this area. A high content of quartz and clay minerals indicates a high fracturability. The nanopores in the shale reservoir are well developed at pore sizes between 2˜10 nm and greater than 1000 nm; however, the pores at the other pore sizes are poorly developed, resulting in weak pore connectivity in the reservoir. According to the results of the PetroMod simulation, the shale of the Taiyuan Formation has undergone two subsidence and two uplift processes. The Yanshanian magmatic intrusion is the key factor for the rapid increase in gas production. In addition, the geological structure of the area is relatively simple, and the burial history and caprock thickness are also the main controlling factors of gas generation and preservation. The shale-sandstone-shale combination and shale-coal-shale combination are the main models of shale gas preservation. This comprehensive study suggests that the shale gas of the Taiyuan Formation in the eastern Qinshui Bain has good potential for exploration and development.
页岩在沁水盆地石炭-二叠系煤系地层中广泛发育，这些页岩具有巨大的页岩气勘探潜力。本文对沁水盆地东部太原组页岩进行了研究。通过野外调查、有机地球化学测试、X射线衍射、扫描电子显微镜、高压压汞、低温液氮吸附和PetroMod模拟等测试手段，对研究区太原组页岩进行调查，以研究其储层特征，如有机地球化学、矿物学、岩石学、孔隙渗透率和天然气埋藏史。结果表明，太原组页岩在全区发育良好，厚度超过60米。平均有机质含量为2.95%，干酪根类型为Ⅲ型。页岩成熟度（平均值为2.45%）对应高成熟演化阶段，表明该地区已生成大量页岩气。石英和粘土矿物含量高表明脆性大。页岩储层中的纳米孔隙在2～10纳米和大于1000纳米的孔径范围内发育良好；然而，其他孔径的孔隙发育较差，导致储层孔隙连通性较弱。根据PetroMod模拟结果，太原组页岩经历了两次沉降和两次隆升过程。燕山期岩浆侵入是天然气产量快速增加的关键因素。此外，该地区地质构造相对简单，埋藏史和盖层厚度也是天然气生成和保存的主要控制因素。页岩-砂岩-页岩组合和页岩-煤-页岩组合是页岩气保存的主要模式。这项综合研究表明，沁水盆地东部太原组页岩气具有良好的勘探开发潜力。
