四川盆地德阳—安岳裂陷槽中段筇竹寺组沉积演化模式与有利相带优选  

Sedimentary evolution model and favorable facies belt selection of the Qiongzhusi Formation in the middle section of the Deyang-Anyue rift in the Sichuan Basin

作　　者：杨一茗 石学文[1,2] 刘文平 吴伟[1,2] 何一凡 李彦佑[1,2] 张亦弛 杨雨然 朱逸青 刘佳 吴喆 YANG Yiming;SHI Xuewen;LIU Wenping;WU Wei;HE Yifan;LI Yanyou;ZHANG Yichi;YANG Yuran;ZHU Yiqing;LIU Jia;WU Zhe(PetroChina Southwest Oil&Gasfield Company,Chengdu 610051,China;Key Laboratory of Shale Gas Evaluation and Extraction in Sichuan Province,Chengdu 610051,China)

机构地区：[1]中国石油西南油气田分公司,四川成都610051 [2]页岩气评价与开采四川省重点实验室,四川成都610051

出　　处：《天然气地球科学》2024年第12期2106-2120,共15页Natural Gas Geoscience

基　　金：中国石油天然气集团有限公司科技项目“新区新层系有利区优选与勘探评价关键技术研究”(编号:2023ZZ21-04);中国石油西南油气田公司科研项目“德阳—安岳裂陷槽筇竹寺组页岩气富集规律研究”(编号:20230304-07);中国石油天然气股份有限公司气藏评价项目“德阳—安岳裂陷槽中段筇竹寺组页岩古地貌刻画及有利区综合评价”联合资助。

摘　　要：兴凯地裂运动造成四川盆地德阳—安岳一带形成拉张型海槽,下寒武统筇竹寺组沉积明显受控于海槽格局,其内部发育多套黑色炭质页岩和灰黑色粉砂质页岩,经勘探证实具有巨大的开发潜力。但目前关于筇竹寺组沉积相、沉积模式及有利相带的认识还不清楚,制约了勘探开发的长远部署。为此,借助大量岩心、薄片及扫描电镜等宏微观观测技术,结合地球物理资料、关键地质参数分析,总结出德阳—安岳裂陷槽中段筇竹寺组沉积学相标志、地球物理相标志及定量化相标志,精细解剖筇竹寺组的沉积相带分布,建立德阳—安岳裂陷槽中段筇竹寺组页岩的沉积演化模式,并通过对比矿物组分、TOC、U/Th、Y/Ho及页岩厚度等指标,优选出有利相带。研究结果表明:(1)筇竹寺组可划分为陆隆、陆坡和陆棚3类亚相,其中陆棚以海槽为界,进一步划分为槽内深水陆棚相和槽外浅水陆棚相,依据沉积特征及环境差异性进一步划分出硅质泥棚相、(含)粉砂质泥棚相、泥质粉砂棚相和粉砂棚相等微相;(2)筇竹寺组自下而上水体持续变浅,处于完整的海退序列,沉积早期具有资阳、威远—自贡及长宁区块3个沉积中心,随着地层阶段性填平海槽,深水区域逐渐向北迁移;(3)槽内深水陆棚亚相中的(含)粉砂质泥棚相和硅质泥棚相矿物组分相对稳定且长石含量高,TOC含量高且保存条件好,是筇竹寺组页岩的有利相带,主要发育于资阳、威远地区。The Xingkai rifting resulted in the formation of an extensional trough in the Deyang-Anyue area of the Sichuan Basin.The deposition of the Lower Cambrian Qiongzhusi Formation is obviously controlled by the trough pattern,and many sets of black carbonaceous shale and gray-black silty shale are developed inside it.It has been proved by exploration that it has great development potential.However,the understanding of sedimen⁃tary facies,sedimentary model and favorable facies belt of Qiongzhusi Formation is still unclear,which restricts the long-term deployment of exploration and development.Therefore,with the help of a large number of macro and micro observation techniques such as core,thin section and scanning electron microscope,combined with geophysical data and key geological parameter analysis,this study summarizes the sedimentary facies signs,geophysical facies signs and quantitative facies signs of Qiongzhusi Formation in the middle part of Deyang-Any⁃ue rift trough,finely dissects the sedimentary facies belt distribution of Qiongzhusi Formation,establishes the sedimentary evolution model of Qiongzhusi Formation shale in the middle part of Deyang-Anyue rift trough,and compares the mineral composition,TOC,U/Th,Y/Ho,shale thickness and other indicators to optimize the favorable facies belt.The results show that:The Qiongzhusi Formation can be divided into three subfacies:Continental uplift,continental slope and continental shelf.The continental shelf is further divided into deep-wa⁃ter shelf facies in the trough and shallow-water shelf facies outside the trough with the trough as the boundary.According to the sedimentary characteristics and environmental differences,it is further divided into siliceous mud shelf facies,(including)silty mud shelf facies,muddy silty sand shelf facies and muddy silty sand shelf fa⁃cies.

关 键 词：沉积模式 沉积相 有利相带 四川盆地 筇竹寺组 深层页岩 德阳—安岳裂陷槽 

分 类 号：TE122.1[石油与天然气工程—油气勘探]