摘要
川东南志留系小河坝组具有良好的生储盖组合,勘探前景较好,但小河坝组的沉积学和地球化学等基础研究薄弱,制约了目的层系的油气勘探。以川东南回龙场地区为例,系统采集了研究区小河坝组101个样品,利用常量及微量元素分析了小河坝组古沉积环境及其演化特征。结果表明,小河坝组主要形成于淡水—微咸水、温暖潮湿、弱氧化—弱还原的浅水三角洲沉积环境;纵向上,海平面变化表现为2个海侵—海退旋回,自下而上划分为X1、X2、X3和X4共4段。X1、X3段为海侵体系域(TST),气候温暖湿润,古盐度较低,水体还原性强,古水深较深;X2、X4段为高水位体系域(HST),气候干燥炎热,古盐度较高,水体还原性弱,古水深较浅。
The Silurian Xiaoheba Formation in the southeastern Sichuan Basin has a good source-reservoir-seal assemblage and excellent geological conditions for hydrocarbon preservation.However,fundamental geochemical and sedimentological studies of Xiaoheba Formation are limited,and exploration activity is restricted.To solve this problem,101 samples were collected from Huilongchang section in southeast Sichuan Basin,and palaeosedimentary environment and evolutionary characteristics were analyzed by using major and trace elements.The analytical results show that the Xiaoheba Formation was mainly formed in the shallow water delta within freshwater-brackish seawater,under a warm,humid,and weakly oxidized-weakly reduced condition.The sea level change of Xiaoheba Formation was divided into two transgression-regression cycles,which was divided into four sections X1,X2,X3 and X4 from bottom to top.X1 and X3 sections were transgressive system tracts(TST),with warm and humid climate,lower paleosalinity,strong water reducibility and upper paleo water depth.X2 and X4 sections were high system tracts(HST),with dry and hot climate,high paleosalinity,weak water reducibility and shallower paleo water depth.
作者
张昭丰
王良军
张立强
黎承银
ZHANG Zhao-feng;WANG Liang-jun;ZHANG Li-qiang;LI Cheng-yin(School of Geosciences,China University of Petroleum(East China),Qingdao 266580,China;SINOPEC Exploration Company,Chengdu 610041,China)
出处
《天然气地球科学》
EI
CAS
CSCD
北大核心
2020年第9期1239-1249,共11页
Natural Gas Geoscience
基金
国家科技重大专项(编号:2016ZX05002-004)
中国科学院战略先导科技专项(编号:XDA14010202)
中国石油天然气股份有限公司重大科技专项(编号:ZD2019-183-001)联合资助。
关键词
川东南
小河坝组
元素分析
沉积环境
Southeast Sichuan Basin
Xiaoheba Formation
Elemental analysis
Sedimentary environment