川南D区龙马溪组页岩有机质孔隙发育特征及影响因素  

Development characteristics and influencing factors of organic matter pores in Longmaxi Formation shale in D area,southern Sichuan Basin,China

作　　者：曹茜 温真桃[4] 徐浩[5] 戚明辉 王兴志[1] CAO Qian;WEN Zhentao;XU Hao;QI Minghui;WANG Xingzhi(School of Earth Science and Technology,Southwest Petroleum University,Chengdu 610091,China;Key Laboratory Shale Gas Evaluation and Exploitation of Sichuan Province,Chengdu 610091,China;Sichuan Keyuan Testing Center of Engineering Technology,Chengdu 610091,China;Exploration and Development Research Institute of Southwest Oil and Gas Company,SINOPEC,Chengdu 610041,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]西南石油大学地球科学与技术学院,成都610091 [2]页岩气评价与开采四川省重点实验室,成都610091 [3]四川省科源工程技术测试中心,成都610091 [4]中国石化西南油气分公司勘探开发研究院,成都610041 [5]油气藏地质及开发工程国家重点实验室(成都理工大学),成都610059

出　　处：《成都理工大学学报（自然科学版）》2021年第5期599-609,625,共12页Journal of Chengdu University of Technology: Science & Technology Edition

基　　金：2020年中央引导地方科技发展专项(2020ZYD027);四川省省院省校合作项目(2018JZ0003)。

摘　　要：研究川南D区下志留统龙马溪组页岩中不同类型有机质孔隙的结构特征及影响因素。通过氩离子抛光和扫描电镜技术对川南D区不同钻井优质页岩段样品有机质孔隙进行系统观察,结合ImageJ图像处理软件对不同类型有机质孔隙结构特征参数进行统计分析,探讨有机质孔隙发育的主控因素。结果表明:不同类型有机质的孔隙发育程度不同,孤立有机质中有机质孔隙以微孔和小孔为主,孔隙多呈孤立状分布,整体呈定向排列;共生有机质(硅质矿物粒间孔中充填的固体沥青、黏土矿物粒间孔充填的有机质以及黄铁矿颗粒间充填的有机质)中有机质孔隙发育,孔隙直径相对较大,偶见少量微孔发育,对应孔隙圆度相对较高。不同钻井中有机质孔隙直径、形状系数及分形维数具有一定的差异性。有机质孔隙的发育主要受控于地层压力及黏土矿物、黄铁矿等无机矿物的分布,其中超压对于页岩有机质孔隙保存起重要作用,黏土矿物转化以及黄铁矿的形成对相邻的有机质聚集和转化生孔起明显催化作用。Organic pores occurred in the Lower Silurian Longmaxi Formation shale in D area of southern Sichuan Basin are important storage space for oil and gas accumulation.Argon ion polishing and scanning electron microscopy are used to systematically observe the organic matter pores of different high quality shale samples from different drilling wells in D block,and the characteristic parameters of different types of organic matter pore structures are statistically analyzed with ImageJ image processing software so as to explore the main controlling factors of organic matter pore development.The results indicate that different types of organic matters display different pore development degree.In fact,in the isolated organic matter,the pores of organic matter are mainly micropores and tiny pores,and most of the pores are isolated in space with preferred orientation.The symbiotic organic matter in the shale is characterized by solid asphalt filled in intergranular pores of siliceous minerals,organic matter filled in intergranular pores of clay minerals and organic matter filled in intergranular pores of pyrite.Large pore diameter organic pores usually occur in the symbiotic organic matter and micropores with relatively high pore roundness also develop occasionally in the symbiotic organic matter.The pore diameter,shape coefficient and fractal dimension of organic matter are varied in different drilling samples.It is proposed that the development of organic matter pores is mainly controlled by the formation pressure and the distribution of inorganic minerals(such as clay minerals and pyrite).The formation overpressure plays an important role in the preservation of organic matter pores,and the transformation of clay minerals and the formation of pyrite play an obvious catalytic role in the accumulation and transformation of organic matter in the shale adjacent to clay minerals and pyrite.

关 键 词：孤立有机质 共生有机质 有机质孔隙 孔隙结构参数 影响因素 

分 类 号：TE122[石油与天然气工程—油气勘探]