四川盆地东部海相下组合油气勘探领域与有利勘探方向  

Petroleum Exploration Domains and Favorable Directions of the Lower Marine Assemblage in Eastern Sichuan Basin

作　　者：孙自明[1] 张荣强[1] 孙炜[1] 郝运轻[1] 卞昌蓉[1] SUN Ziming;ZHANG Rongqiang;SUN Wei;HAO Yunqing;BIAN Changrong(SINOPEC Petroleum Exploration and Production Research Institute,Beijing 100083,China)

机构地区：[1]中国石化石油勘探开发研究院,北京100083

出　　处：《现代地质》2021年第3期798-806,共9页Geoscience

基　　金：国家重点研发计划“深地资源勘查开采”专项“超深层及中新元古界盖层封闭性与油气保存机理”(2017YFC0603105);中国石化科技项目“四川盆地东部下组合新领域及突破目标评价”(P19022-3)。

摘　　要：四川盆地是一个大型叠合含油气盆地,经历了多期伸展-聚敛旋回,资源潜力巨大。近年来,盆地中部下组合天然气勘探在震旦系灯影组和下寒武统龙王庙组获得重大突破,但盆地东部尚未获得实质性进展,有利勘探方向尚待明确。以构造-沉积演化分析为基础,将盆地东部及邻区海相下组合划分为伸展分异台地(震旦纪至早寒武世沧浪铺期)、稳定统一台地(早寒武世龙王庙期至中奥陶世宝塔期)和挤压前陆坳陷(晚奥陶世至志留纪)三个演化阶段;根据油气成藏要素和运聚特征,划分出寒武系盐下碳酸盐岩、寒武系盐上碳酸盐岩和志留系致密碎屑岩等三个油气勘探领域,不同勘探领域制约油气成藏和富集的关键因素差异较大;指出了川东南震旦系灯影组四段台缘带、川东寒武系洗象池群碳酸盐岩浅滩和志留系小河坝组大型三角洲砂体等,为盆地东部海相下组合的有利勘探方向,同时明确了重点突破地区。Sichuan Basin is a large superimposed petroliferous basin with great resource potential,which has experienced multi-stage extensional-compressional cycle.Few substantial gas exploration discoveries have been obtained so far in eastern Sichuan Basin while a series of natural gas exploration discoveries have been obtained in Dengying formation of the Upper Sinian system and Longwangmiao Formation of the Lower Cambrian system in recent years in the middle basin.By analysis of tectonic and sedimentary evolution,three evolutionary stages were built up from the Sinian period to the Silurian period in the eastern Sichuan basin and its adjacent areas:(1)extensional differentiation platform stage(from Sinian period to the Canglangpu phase of Early Cambrian period),(2)stable unified platform stage(from the Longwangmiao phase of Early Cambrian period to the Baota phase of the Middle Ordovician period),and(3)compressional foreland depression stage(Late Ordovician period to Silurian period).According to the comprehensive analysis of petroleum geological elements and the characteristics of hydrocarbon migration and accumulation,three hydrocarbon exploration domains are recognized,which are(1)pre-salt carbonate exploration domain(Sinian system to Gaotai Formation of the Middle Cambrian system),(2)post-salt carbonate exploration domain(Xixiangchi group of Middle-Upper Cambrian system to Baota Formation-Linxiang Formation of Middle-Upper Ordovician),and(3)tight clastic rock exploration domain(Upper Ordovician to Silurian system)from lower to upper,respectively.There exists major differences in the aspects of petroleum geological elements,characteristics of migration and accumulation of hydrocarbon,and main controlling factors,and therefore the key constraints of petroleum exploration are different in different exploration domains.By systematic evaluation of the exploration domains,it is pointed out that the carbonate platform marginal zone of the fourth member of the Dengying Formation in southeastern Sichuan basin,the carbonate

关 键 词：勘探领域 有利勘探方向 沉积-构造演化 四川盆地东部 

分 类 号：TE132[石油与天然气工程—油气勘探]