川中地区大安寨段页岩热演化史及油气地质意义  

Thermal Evolution History of Shale in Da’anzhai Member and Its Petroleum Geological Significance in Central Sichuan Basin

作　　者：蒋奇君 李勇[1,2] 肖正录[1,2] 路俊刚 秦春雨[3] 张少敏 JIANG Qijun;LI Yong;XIAO Zhenglu;LU Jungang;QIN Chunyu;ZHANG Shaomin(Southwest Petroleum University,School of Geoscience and Technology,Chengdu,Sichuan 610500,China;Southwest Petroleum University,Sichuan Key Laboratory of Natural Gas Geology,Chengdu,Sichuan 610500,China;Research Institute of Exploration and Development,Southwest Oil&Gasfield Company,PetroChina,Chengdu,Sichuan 610051,China)

机构地区：[1]西南石油大学地球科学与技术学院,成都610500 [2]西南石油大学天然气地质四川省重点实验室,成都610500 [3]中国石油西南油气田分公司勘探开发研究院,成都610051

出　　处：《新疆石油地质》2024年第3期262-270,共9页Xinjiang Petroleum Geology

基　　金：中国石油-西南石油大学创新联合体科技合作项目(2020CX050000)。

摘　　要：下侏罗统自流井组大安寨段为四川盆地陆相页岩油开发的最有利层段,页岩油勘探潜力巨大,然而对该地层的热演化史缺乏系统研究。利用含油气盆地模拟系统,对比分析了川中地区北部与中部大安寨段页岩热演化及生烃差异,并探讨其对页岩油富集的影响。研究区大安寨段页岩现今热演化程度由西南向东北逐渐增高,平面上可分为高成熟区和成熟区。高成熟区位于研究区北部,镜质体反射率为1.3%~1.7%,主要发育Ⅲ型有机质,在晚侏罗世早期进入早期生油阶段,晚侏罗世末达到生烃高峰,存在2期生烃作用;成熟区位于研究区中—南部,镜质体反射率为0.9%~1.3%,主要发育Ⅱ1型—Ⅱ2型有机质,侏罗系沉积厚度相对较小,有机质成熟时期较晚,晚侏罗世末进入早期生油阶段,早白垩世进入生烃高峰,仅有1期生烃过程。相较于北部地区,中部地区沉积了大套的富有机质页岩,是大安寨段页岩油坚实的物质基础,但古近纪以来的构造抬升与地层剥蚀,对该区的油气保存具有一定的破坏作用。The Da’anzhai member of the Lower Jurassic Ziliujing formation is the most favorable layer for the development of continental shale oil in the Sichuan basin,and has huge potential in shale oil exploration.However,there is a lack of systematic research on the ther⁃mal evolution history of this formation.Using the simulation system for petroliferous basins,the differences in the thermal evolution and hy⁃drocarbon generation of the shales in Da’anzhai member between the northern part and the central part of the central Sichuan basin were comparatively analyzed,and their impacts on shale oil enrichment were discussed.The thermal evolution degree of the shale of Da’anzhai member in the study area gradually increases from southwest to northeast,and the shale can be divided into a highly matured zone and a matured zone on the plane.The highly matured zone is located in the northern part of the study area,with vitrinite reflectance ranging from 1.3%to 1.7%,mainly developing TypeⅢorganic matter.The early oil generation occured in the early Late Jurassic,and the oil generation peaked at the end of Late Jurassic,experiencing two phases of hydrocarbon generation.The matured zone is located in the central to south⁃ern parts of the study area,with vitrinite reflectance ranging from 0.9%to 1.3%,mainly developing TypeⅡ1-Ⅱ2 organic matter.The sedi⁃mentary thickness of the Jurassic is relatively small,the early oil generation occured at the end of the Late Jurassic and reached the peak in the Early Cretaceous,with only one period of hydrocarbon generation.Compared with the northern area,a large set of organic⁃rich shales deposited in the central area,which provieded a solid material basis for shale oil in the Da’anzhai member.However,the tectonic uplift and stratum erosion since the Paleogene posed a certain destructive effect on the preservation of oil and gas in this area.

关 键 词：四川盆地 下侏罗统 自流井组 大安寨段 热演化史 生烃能力 保存条件 页岩油气 

分 类 号：TE122[石油与天然气工程—油气勘探]