四川盆地海相页岩孔隙类型对孔隙空间贡献定量表征  

Quantitative characterization of the contribution of pore types to pore space of marine shale in Sichuan Basin

作　　者：惠沙沙 庞雄奇[1,2] 谌卓恒 王琛茜 施砍园 胡涛[1,2] 胡耀 李敏[1,2] 梅术星 黎茂稳 Hui Shasha;Pang Xiongqi;Chen Zhuoheng;Wang Chenxi;Shi Kanyuan;Hu Tao;Hu Yao;Li Min;Mei Shuxing;Li Maowen(National Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum(Beijing),Beijing 102249,China;College of Geoscience,China University of Petroleum(Beijing),Beijing 102249,China;Geological Survey of Canada,Natural Resources Canada,Calgary T2 L2 A7,Canada;Sinopec Petroleum Exploration and Production Research Institute,Beijing 100083,China)

机构地区：[1]油气资源与工程全国重点实验室,中国石油大学(北京),北京102249 [2]中国石油大学(北京)地球科学学院,北京102249 [3]加拿大联邦地质调查局,加拿大卡尔加里T2 L2 A7 [4]中国石油化工股份有限公司石油勘探开发研究院,北京100083

出　　处：《石油学报》2024年第3期531-547,共17页Acta Petrolei Sinica

基　　金：国家自然科学基金企业创新发展联合基金项目(No.U19B6003-02);2022年度美国石油地质学家协会(AAPG)全球研究生助研金项目(22269437)资助。

摘　　要：为定量表征四川盆地古生界海相页岩孔隙类型对页岩微米—纳米孔隙空间的相对贡献,基于岩石学分析、地球化学分析、低温氮气吸附实验、场发射扫描电镜观察等方法对不同热演化阶段的海相页岩的孔隙类型及结构进行了对比分析,结合页岩的TOC含量和矿物组分信息,利用基于机器学习的图像分析方法提取页岩孔隙的几何参数,定量计算了不同热演化阶段海相页岩中不同类型孔隙的孔面积和孔体积。研究结果表明:随成熟度增加,四川盆地海相页岩中孔隙的平均孔径减小,而孔体积、孔面积、表面分形维数和结构分形维数均增大;在上二叠统大隆组低成熟海相页岩中,骨架矿物相关孔最为发育,其贡献了70%的孔面积和73%的孔体积;在志留系龙马溪组成熟海相页岩中,黏土矿物孔占主要优势,其贡献了63%的孔面积和58%的孔体积;在龙马溪组高成熟—过成熟页岩中,有机质孔贡献了68%的孔面积与52%的孔体积。四川盆地海相页岩的孔隙演化受成岩作用和生烃过程共同影响,明确不同热演化阶段海相页岩的优势孔隙类型可以为页岩油气高效开发提供理论指导。This study aims to quantitatively characterize the relative contribution of pore types to the micro-nano pore space of Paleozoic marine shale in Sichuan Basin.Based on petrological analysis,geochemical analysis,low-temperature nitrogen adsorption experiment and field emission scanning electron microscopy observation,comparison and analysis were performed on the pore types and structure of marine shale in different thermal evolution stages.Combined with the total organic carbon(TOC)content and mineral composition of shale,the geometric parameters of shale pores were extracted by means of image analysis based on machine learning,and then the pore surface area and pore volume of different types of pores in marine shale at different evolution stages were quantitatively calculated.The results show that with the increase of maturity,the average pore size of marine shale in Sichuan Basin is decreased,while the pore surface area,pore volume,surface fractal dimensions,and structure fractal dimension are increased.In the low-mature marine shale of the Upper Permian Dalong Formation,the mineral-related pores were the most developed,providing 70%of pore surface area and 73%of pore volume.The mature marine shale of the Silurian Longmaxi Formation was dominated by clay mineral pores,which provided 63%of pore surface area and 58%of pore volume.In the high-mature and over-mature shale of Longmaxi Formation,organic pores contributed to 68%of pore surface area and 52%of pore volume.The pore evolution of marine shale in Sichuan Basin is jointly influenced by diagenesis and hydrocarbon generation process.It is of important significance to clarify the dominant pore types of marine shale at different thermal evolution stages,thus providing theoretical guidance for the efficient development of shale oil and gas.

关 键 词：海相页岩 孔隙类型 孔隙结构 孔隙演化 图像分析 定量表征 四川盆地 上二叠统大隆组 志留系龙马溪组 

分 类 号：TE122.2[石油与天然气工程—油气勘探]