摘要
以四川盆地南部110口页岩气评价井的岩性、沉积构造、笔石带、无机地球化学特征以及电性资料为基础,利用扫描电镜矿物定量分析技术,对上奥陶统凯迪阶—赫南特阶至留系兰多列维统鲁丹阶—埃隆阶进行层序划分并分析沉积特征与四级层序演化规律。目的层可以划分为SQ1、SQ2两个层序,依据奥陶系—志留系沉积背景、目的层伽马值以及铀与钍的质量分数之比可以识别5个最大海泛面和12个体系域,根据体系域及其组合,可划分8个四级层序,由老至新为Pss1—Pss8。确定了川南地区凯迪阶—埃隆阶优势页岩岩相的发育时期,预测了发育规模,最优质的岩相包括含白云石/方解石硅质页岩相、硅质页岩相、含黏土硅质页岩相、含长石硅质页岩相,主要发育在威远、渝西、泸州地区的Pss3—Pss5和长宁西部—泸州北部—渝西中部地区的Pss6以及长宁地区的Pss3—Pss4,次优质的硅质黏土质页岩相主要发育在Pss6的泸州地区南部—长宁地区(不含长宁西部)、威远地区东部—渝西地区北部以及泸州地区南部的Pss7、泸州地区北部—威远地区—渝西地区的Pss8。建立了川南地区凯迪阶—埃隆阶四级层序演化模型,Pss1—Pss8海平面经历6退5进,冰期后的第1次海侵SQ2-MFS1是级别最大的一次海泛面。图6表1参32.
Based on the lithologies,sedimentary structures,graptolite zones,inorganic geochemical characteristics,electrical data of 110 shale gas wells in southern Sichuan Basin and the mineral quantitative analysis technology of scanning electron microscope,the stratigraphic sequences of Upper Ordovician Katian Stage–Himantian Stage–Silurian Rhuddanian Stage–Aeronian Stage are divided,the sedimentary characteristics and fourth-order sequence evolution are analyzed.The target layer can be divided into two sequences,SQ1 and SQ2.According to Ordovician–Silurian sedimentary background,target layer GR and w(U)/w(Th),5 maximum flooding surfaces and 12 system tracts are identified.According to system tracts and their combinations,eight fourth-order sequences are identified,namely,Pss1–Pss8 from old to new.The development period and scale of dominant shale facies from Katian stage to Aeronian stage in southern Sichuan are restored.The best-quality dolomite/calcite-bearing siliceous shale facies,siliceous shale facies,clay-bearing siliceous shale facies and feldspar-bearing siliceous shale facies mainly occur in Pss3–Pss5 of Weiyuan,Western Chongqing and Luzhou,Pss6 of Western Changning–Northern Luzhou–Central Western Chongqing and Pss3–Pss4 of Changning.The siliceous clay shale facies second in quality mainly occurs in Pss6 of Southern Luzhou–Changning area(excluding Western Changning area),Pss7 of Eastern Weiyuan–Northern Western Chongqing–Southern Luzhou and Pss8 of Northern Luzhou–Weiyuan–Western Chongqing.The fourth-order sequence evolution model of Katian stage–Aeronian stage in southern Sichuan is established.During the depositional period of Pss1–Pss8,the sea level had six regressions and five transgressions,and the first transgression SQ2-MFS1 after glaciation was the largest flooding surface.
作者
朱逸青
陈更生
刘勇
石学文
吴伟
罗超
杨雪
杨雨然
邹源红
ZHU Yiqing;CHEN Gengsheng;LIU Yong;SHI Xuewen;WU Wei;LUO Chao;YANG Xue;YANG Yuran;ZOU Yuanhong(PetroChina Southwest Oil&Gasfield Company,Chengdu 610051,China)
出处
《石油勘探与开发》
SCIE
EI
CAS
CSCD
北大核心
2021年第5期974-985,共12页
Petroleum Exploration and Development
基金
中国石油重大工程技术现场试验项目“深层页岩气地质综合评价技术现场试验”(2019F-31-01)
中国石油西南油气田公司博士后项目“四川盆地南部五峰组—龙马溪组沉积环境及其对页岩储层的控制作用研究”(20200304-03)。
关键词
四川盆地南部
凯迪阶—埃隆阶
五峰组
龙马溪组
层序地层
岩相古地理
southern Sichuan Basin
Katian Stage–Aeronian Stage
Wufeng Formation
Longmaxi Formation
sequence stratigraphy
lithofacies palaeogeography
