四川盆地湄潭组生烃潜力分析及勘探意义  

Hydrocarbon Potential Analysis and Exploration Significance of the Meitan Formation,Sichuan Basin

作　　者：张殿伟[1] 郝运轻 张荣强[1] 孙炜[1] 高平 李甘璐 ZHANG DianWei;HAO YunQing;ZHANG RongQiang;SUN Wei;GAO Ping;LI GanLu(Petroleum Exploration and Production Research Institute,SINOPEC,Beijing 100083,China;School of Energy Resources,China University of Geoscience(Beijing),Beijing 100083,China;College of Geosciences,China University of Petroleum(Beijing),Beijing 102249,China)

机构地区：[1]中国石油化工股份有限公司石油勘探开发研究院,北京100083 [2]中国地质大学(北京)能源学院,北京100083 [3]中国石油大学(北京)地球科学学院,北京102249

出　　处：《沉积学报》2020年第3期635-647,共13页Acta Sedimentologica Sinica

基　　金：中科院A类先导专项(XDA010406)。

摘　　要：四川盆地油气资源丰富,盆地内发育多套富有机质泥页岩,并形成了多套优质生储盖组合。奥陶系是四川盆地下组合目前勘探关注的重要层系,但尚未取得重要油气勘探突破,该成藏组合是否存在烃源岩是该层系油气勘探关注的核心问题之一。下奥陶统湄潭组主要为一套陆棚相泥页岩沉积,分布广、厚度大,其生烃潜力备受关注。基于地层发育特征,通过岩性组合分析、古生物鉴定和微量元素测试,并结合有机质丰度(TOC)参数,结果显示四川盆地在湄潭组沉积期存在川南和川北两个沉积中心:川南沉积中心厚度大,但砂岩或砂质含量多,不利于烃源岩发育;川北沉积中心湄潭组岩性主要为深灰色—灰黑色泥岩、页岩和粉砂质泥岩;疑源类化石和微量元素组成表明沉积环境利于烃源岩发育,TOC达到一般烃源岩标准,因此认为川北地区存在湄潭组烃源岩沉积中心。通过湄潭组有机地球化学分析和源储匹配成藏解剖,结合烃源岩空间分布预测认为,湄潭组烃源岩能为川北—川东北地区上寒武统—奥陶系油气成藏提供烃源保障;以湄潭组为烃源,可形成上生下储、源储通过不整合相接的“湄潭组生—上寒武统洗象池组储”有利成藏组合和下生上储、源储通过断层相接的“湄潭组生—中奥陶统宝塔组储”的潜在成藏组合。湄潭组生烃潜力的确认和2种成藏组合的建立,扩大了川北—川东北地区勘探空间,对上寒武统—奥陶系实现勘探突破具有重要意义。The Sichuan Basin is rich in oil and gas resources because of the development of multiple sets of rich or-ganic mud shale and combinations of high-quality reservoir and cap rocks.Close attention has been paid to the Ordovi-cian series,but no significant breakthrough has been made in oil and gas exploration.One of the key issues is the ex-istence of source rocks in the Ordovician series.The Lower Ordovician Meitan Formation consists mainly of a set of widely distributed shelf-facies mud shale of large thickness,whose hydrocarbon generation potential has received some attention.Based on the characteristics of formation development,lithological combination analysis,paleontolog-ical identification and trace element tests,combined with organic matter abundance parameters(TOC),it is conclud-ed that there were two sedimentary centers in the Sichuan Basin during the sedimentary period of the Meitan Forma-tion.The southern sedimentary center is the thicker,but contains higher sandstone or sandy content which is not con-ducive to source rock development.In the northern sedimentary center the Meitan Formation is characterized by dark-gray to black mudstone,shale and silty mudstone.The presence of acritarch fossils,together with the trace element composition,indicate that the sedimentary environment was conducive to the development of hydrocarbon source rocks,and the TOC is at the standard of source rocks generally.Therefore,it is believed that there is a source rock sedimentary center in the Meitan Formation in the northern Sichuan Basin.Based on an analysis of the organic geo-chemistry and accumulation anatomy combined with the predicted spatial distribution of the source rocks of the Meit-an Formation,it is concluded that they provide a source of hydrocarbon accumulation in the late Cambrian to Ordovi-cian.Overall,in the Meitan Formation it is predicted that a maximum source rock thickness of 40-50 m is located be-tween wells Mashen1,Chuanshen1 and Wutan1.With an average 0.84%TOC and 2.25%Ro,the hydrocarbon gener-ation in

关 键 词：川北 湄潭组 沉积中心 生烃潜力 勘探意义 

分 类 号：P618.13[天文地球—矿床学]