渝东南龙马溪组下部页岩岩石学特征与优质储层形成机理

发布时间：2019-06-28 20:13

【摘要】：以渝东南綦江、南川、石柱及涪陵的龙马溪组下部页岩为例,通过X射线衍射、氩离子抛光-场发射扫描电镜、TOC、脆性力学、高压压汞实验、低温氮吸附实验等测试手段,综合探明页岩储层矿物组分、有机质特征、孔隙特征、力学脆性等岩石学特征,对储层进行岩石学角度的评价,并讨论岩石学特征对优质储层形成的影响。结果显示:龙马溪组下部页岩储层岩石矿物组分可以分为以石英为主的脆性矿物和以伊利石为主的黏土矿物,底部脆性矿物含量更高;TOC平均值高于2%,达到过成熟阶段;孔隙类型复杂,识别出有机质纳米孔、黏土矿物片状孔、骨架矿物溶蚀孔等多种形貌-成因孔隙,纳米孔提供了主要的比表面积和储集空间;孔隙形貌复杂,发育平行板状等多种形态类型;岩石力学脆性较好,有利于微裂隙发育与压裂造缝。研究区龙马溪组下部页岩形成于深海陆棚相,经历了晚成岩作用阶段,矿物组分适宜,纳米孔、微裂隙发育,具有较好的力学脆性,是具有特殊岩石学特征的优质页岩气储层。页岩储层的岩石物质组成特征是优质储层形成的基础,从岩石学特征的角度对储层展开研究,对探究页岩储层的物性成因及其受控因素具有重要意义。
[Abstract]:Taking the lower shale of Longmaxi formation in Qijiang, Nanchuan, Shizhu and Fuling of southeast Chongqing as examples, the petrological characteristics of shale reservoir are evaluated by means of X-ray diffraction, argon ion polishing and field emission scanning electron microscope, TOC, brittleness mechanics, high pressure mercury injection experiment and low temperature nitrogen adsorption experiment to comprehensively find out the petrological characteristics of shale reservoir, such as mineral composition, organic matter characteristics, pore characteristics, mechanical brittleness and so on. The influence of petrological characteristics on the formation of high quality reservoirs is also discussed. The results show that the rock mineral components of the lower shale reservoir of Longmaxi formation can be divided into brittle minerals dominated by quartz and clay minerals dominated by Illite, and the content of brittle minerals at the bottom is higher, the average value of TOC is higher than 2%, and reaches the overmature stage. The pore types are complex, and many kinds of morphologies, such as organic matter nanoporous, clay mineral flake pore, skeleton mineral dissolution pore and so on, are identified, which provide the main specific surface area and reservoir space; the pore morphology is complex and parallel plate shape is developed, and the rock mechanics brittleness is good, which is beneficial to the development of microfracture and fracturing fracture. The shale in the lower part of Longmaxi formation in the study area was formed in the deep-sea shelf phase and experienced late diagenetic stage. It has suitable mineral components, nano-pores and microfissures, and has good mechanical brittleness. It is a high quality shale gas reservoir with special petrological characteristics. The rock material composition characteristics of shale reservoir are the basis of high quality reservoir formation. It is of great significance to study the reservoir from the point of view of petrological characteristics in order to explore the physical origin and controlled factors of shale reservoir.
【作者单位】：中国矿业大学资源与地球科学学院;煤层气资源与成藏过程教育部重点实验室;中国石油大学(北京)地球科学学院;河南理工大学资源环境学院;
【基金】：国家重点基础研究发展计划(973)项目(2012CB214702) 煤层气资源与成藏过程教育部重点实验室(中国矿业大学)开放基金资助项目(2015-007);中国矿业大学大学生创新训练项目(201560)
【分类号】：P618.13

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