四川盆地中二叠统含海泡石层系源储组合新模式及其油气勘探新领域  

A new model of source-reservoir association and new fields of oil and gas exploration in the Middle Permian sepiolite bearing strata,Sichuan Basin,China

作　　者：宋金民[1] 刘树根[1,2] 金鑫 汪华[3] 范建平 江青春 田小彬[5] 叶玥豪[1] 李亚[3] 李智武 杨迪[1] 王佳蕊[1] 罗平 SONG Jinmin;LIU Shugen;JIN Xin;WANG Hua;FAN Jianping;JIANG Qingchun;TIAN Xiaobin;YE Yuehao;LI Ya;LI Zhiwu;YANG Di;WANG Jiarui;LUO Ping(State Key Laboratory of Oil and Gas Reservoir Geology and Exploration, Chengdu University of Technology, Chengdu 610059, China;Xihua University, Chengdu 610039, China;Research Institute of Petroleum Exploration and Development, PetroChina Southwest Oil and Gas Field Company, Chengdu 610041, China;PetroChina Research Institute of Petroleum Exploration and Development, Beijing 100083, China;Exploration and Development Research Institute of Daqing Oilfield Company,PetroChina, Daqing 163712, China)

机构地区：[1]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 [2]西华大学,成都610039 [3]中国石油西南油气田分公司,成都610041 [4]中国石油勘探开发研究院,北京100083 [5]大庆油田勘探开发研究院,黑龙江大庆163712

出　　处：《成都理工大学学报（自然科学版）》2022年第2期129-149,共21页Journal of Chengdu University of Technology: Science & Technology Edition

基　　金：国家自然科学基金企业联合基金企业配套项目(P19038);国家自然科学基金面上项目(41872150)。

摘　　要：通过剖面实测、岩心观察、薄片鉴定、氩离子抛光、X射线衍射和扫描电镜等手段,对四川盆地中二叠统栖霞组和茅口组海泡石的特征、产状、成矿机理以及含海泡石层系源(烃源岩)储(储层)配置新模式进行探讨,旨在丰富对二叠系的认识,促进油气勘探。研究表明,四川盆地中二叠统海泡石为层链状结构的海泡石-坡缕石族黏土矿物,比表面积大,吸附能力强;主要为层状自生矿物、透镜状和交代生屑状3种赋存状态,多形成海泡石-滑石-燧石的共生矿物组合;大多数海泡石属海相沉积型成因,由火山活动引发的富SiO_(2)流体与较高的碱度(pCO_(2)低、pH值为8~9.5)、中等盐度的海水混合后直接沉淀形成。海泡石吸附和聚集有机质,提升了烃源岩的品质和生烃潜力,使中二叠统含海泡石层系的有机碳质量分数为0.5%~1.5%,平均值为1.16%,生气强度在(10~22)×10^(8) m^(3)/km^(2),为中等烃源岩。海泡石在中-深埋藏期的成岩转化过程中形成大量的有机质孔和黏土微孔,形成优质的非常规储层;同时释放镁离子和水分子,富镁成岩转化水在流体势的驱动下使高部位生屑滩相灰岩发生白云石化,形成优质常规层状白云岩储层,由此形成自生自储和旁(下)生侧(上)储型的新型高效源储配置模式,提升了栖霞组和茅口组的油气勘探潜力。海泡石层系的厚度分布指示四川盆地中二叠世“两台一凹”的构造-沉积格局;距含海泡石层系沉积中心20 km内、含海泡石层系厚度在40~60 m范围内区域为(古)油气藏的有利分布区。含海泡石层系可形成两大类(古)油气藏,即凹陷边缘的旁生侧储型常规层状白云岩油气藏和凹陷内的自生自储型非常规油气藏。中二叠统非常规油气藏最有利勘探区主要在“C”形的通江-元坝-南充-长寿凹陷内;中二叠统常规油气藏最有利勘探区主要沿凹陷以南的广元-江油-遂宁-重庆和凹陷�The characteristics,occurrence and metallogenic mechanism of sepiolite in the Qixia and Maokou Formations of Middle Permian in Sichuan Basin are studied by means of measured section,core observation,thin section identification,analysis of argon ion polishing,X-ray diffraction and scanning electron microscopy in order to enrich the understanding of Permian system and promote oil and gas exploration.The results show that the Middle Permian sepiolite in Sichuan Basin is a layered chain sepiolite and palygorskite clay mineral with large specific surface area and strong adsorption capacity.It mainly occurs in bedded authigenic minerals,lenticular minerals and metasomatic clastic minerals,and mostly forms sepiolite-talc-chert symbiotic mineral assemblage with marine sedimentary origin.SiO_(2)-rich fluid caused by volcanic activity is directly precipitated after mixing with seawater with high alkalinity(low pCO_(2),pH=8~9.5)and moderate salinity.Sepiolite adsorbed and accumulated organic matter,which improved the quality and hydrocarbon generation potential of the source rocks.Analysis shows that the organic carbon mass fraction of the sepiolite bearing strata in the Middle Permian ranges from 0.5%to 1.5%,with an average of 1.16%and the gas generation intensity of the sepiolite bearing strata is(10~22)×10^(8) m^(3)/km^(2),indicating that the sepiolite bearing strata belong to medium-high quality source rocks.Sepiolite develops a large number of organic pores and clay micropores during the diagenetic transformation of middle-deep burial period,forming high-quality unconventional reservoirs.At the same time,magnesium ions and water molecules are released,and magnesium diagenetic transformation water,driven by fluid potential,results in dolomitization of bioclastic beach facies limestone in high position,forming high-quality conventional stratified dolomite reservoir.Thus,a new efficient source and reservoir configuration model of self-generating and self-storing and side(lower)source and lateral(upper)accumulation was fo

关 键 词：四川盆地 中二叠统 海泡石 源储新模式 油气勘探有利区 

分 类 号：TE122.1[石油与天然气工程—油气勘探] P588.21[天文地球—岩石学]