四川盆地蓬莱地区埃迪卡拉系灯影组二段微生物岩储层成岩作用:对优质储层形成与演化的启示  

Diagenesis of microbial dolomite reservoirs in the second Member of Dengying Formation of Ediacaran in the Penglai area,Sichuan Basin:Insights into the formation and evolution of highquality reservoirs

作　　者：王雅萍 鲍志东[1] 张连进 杨东凡 文雯 钟原 唐攀 WNAG Yaping;BAO Zhidong;ZHANG Lianjin;YANG Dongfan;WEN Wen;ZHONG Yuan;TANG Pan(School of Geosciences,China University of Petroleum(Beijing),Beijing 102249,China;Exploration and Development Research Institute,PetroChina Southwest Oil&Gasfield Company,Chengdu 610041,Sichuan,China;Institute of Logging Technology and Engineering,Yangtze University,Jingzhou 434023,Hubei,China)

机构地区：[1]中国石油大学(北京)地球科学学院,北京102249 [2]中国石油西南油气田分公司勘探开发研究院,四川成都610041 [3]长江大学录井技术与工程研究院,湖北荆州434023

出　　处：《地质力学学报》2024年第4期579-594,共16页Journal of Geomechanics

基　　金：国家重点研发计划专项(2018YFC0604304);中国石油化工股份有限公司科技部专项课题(P23180)。

摘　　要：四川盆地蓬莱地区埃迪卡拉系灯影组二段(灯二段)微生物岩广泛分布,被视为深层碳酸盐岩的潜在油气勘探目标。与常规的孔隙型和岩溶缝洞型优质储层不同,灯二段碳酸盐岩主要由微生物白云岩组成,其优质储层成因及成岩演化过程尚不清晰。研究基于野外露头和钻井取芯资料,结合岩石薄片、扫描电镜、阴极发光、CT扫描等测试手段,对灯影组微生物岩白云岩储层进行详细分析,旨在深入理解成岩作用对孔隙形成及优质储层发育的影响。研究结果显示,研究区微生物岩储层以低孔、特低渗,裂缝-孔隙(洞)型微生物石白云岩为主,储集空间以粒间溶孔、残余格架溶孔、粒内溶孔及中小型溶洞为主,并发育少量晶间孔及晶间溶孔;灯二段经历了多种成岩作用的叠加改造,其准同生溶蚀及早表生溶蚀作用是提高孔隙度的关键因素。研究成果加深了对四川盆地埃迪卡拉系微生物岩优质储层成因的认识,为四川盆地深层油气勘探开发提供了有益信息。[Objective]The microbial dolomite of the second Member of the Dengying Formation(Deng 2 Member)in the Penglai area of the Sichuan Basin is widely distributed and considered a potential target for deep carbonate oil and gas exploration.Unlike conventional high-quality reservoirs characterized by porosity and karst fractures,the carbonate rocks of the Deng 2 Member mainly consist of microbial dolomite.The genesis and diagenetic evolution of these high-quality reservoirs remain unclear.[Methods]This study employed petrographic thin sections,scanning electron microscopy(SEM),cathodoluminescence,and computed tomography(CT)scanning to conduct a detailed analysis of the microbial dolomite reservoirs in the Dengying Formation,using field outcrop and core samples.The aim was to gain a deeper understanding of the effects of diagenesis on pore formation and the development of high-quality reservoirs.[Results and Conclusion]The microbial carbonate reservoirs in the study area were characterized by low porosity and very low permeability,predominantly consisting of fracture-porosity(cavity)type microbial dolomite.The reservoir space was primarily composed of intergranular dissolution pores,residual framework dissolution pores,intragranular dissolution pores,and small to medium-sized dissolution cavities,with minor occurrences of intercrystalline pores and intercrystalline dissolution pores.The Deng 2 Member has undergone multiple diagenetic processes;penecontemporaneous dissolution and early epigenetic dissolution were key factors in enhancing porosity.[Significance]These findings enhance the understanding of the genesis of high-quality microbial carbonate reservoirs in the Ediacaran System of the Sichuan Basin and provide valuable information for deep oil and gas exploration and development in the region.

关 键 词：储层成因 微生物白云岩 灯影组 蓬莱地区 四川盆地 

分 类 号：P618.13[天文地球—矿床学]