基于地震相分析的四川盆地侏罗系凉高山组湖盆演化及页岩发育区预测  

Seismic facies to analyze lacustrine-basin evolution and predict shale blocks extended into the Jurassic Lianggaoshan Formation,Sichuan Basin

作　　者：白桦 洪海涛 邱玉超 张少敏 秦春雨 周红飞 韩璐媛 余凯 BAI Hua;HONG Haitao;QIU Yuchao;ZHANG Shaomin;QIN Chunyu;ZHOU Hongfei;HAN Luyuan;YU Kai(Exploration and Development Research Institute,PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610041,China)

机构地区：[1]中国石油西南油气田公司勘探开发研究院,四川成都610041

出　　处：《天然气勘探与开发》2024年第6期8-17,共10页Natural Gas Exploration and Development

基　　金：中国石油天然气股份有限公司重大科技专项(编号:2024D1ZD-02-01)。

摘　　要：目前针对四川盆地侏罗系凉高山组沉积演化以及页岩发育区的研究较少,缺乏盆地级尺度的湖盆演化及页岩分布的成果认识,难以从盆地角度出发,明确页岩油气勘探方向。为了明确凉高山组湖盆迁移,预测页岩油气勘探方向,立足地震资料,综合录井、测井等分析结果,识别并厘清凉高山组各亚段地震相特征。研究成果表明:(1)凉高山组具有西薄东厚特征,凉一段沉积中心位于川东以及川中东部地区,凉二段沉积中心位于川东以及川东北部地区,凉三段在川东沉积厚度最大;(2)凉高山组识别出4类地震相,其中,Ⅲ类地震相为厚层、连续、强反射地震响应特征,对应于深湖—半深湖沉积页岩发育区;(3)四川盆地凉高山组经历3次湖泛以及对应的湖盆迁移,凉一段深湖—半深湖发育于盆地东部,凉二段时期迁移至盆地中部,凉三段时期发育于盆地中北部;(4)凉一段和凉二段是凉高山组深湖—半深湖页岩主要发育层段,页岩叠合发育区位于平昌—渠县—垫江一带,面积达2.2×10^(4)km^(2),页岩油气勘探潜力大。Currently,there are not systematic studies on both sedimentary evolution in the Jurassic Lianggaoshan Formation of Sichuan Basin and shale blocks extended into the formation,resulting that the basin-scale lacustrine-basin evolution and shale extension remain unknown.It is challenging to pinpoint favorable exploration prospects of shale oil and gas on the basin scale.Thus,seismic-facies attributes were identified for each Lianggaoshan members based on seismic,well-logging and testing data to clarify lacustrine-basin migration and predict shale oil and gas exploration direction for the whole formation.Results show that(i)this formation features thin in the west and thick in the east.And the depocenter in Lianggaoshan 1 Member is located in eastern basin and east of central basin,and that of Lianggaoshan 2 Member in eastern basin and north of eastern basin,and the largest sedimentary thickness of Lianggaoshan 3 Member in eastern basin,respectively;(ii)four categories of seismic facies can be found in this formation.Among them,category III is characterized by big thickness,continuous and strong reflection response,which corresponds to deep to semi-deep lacustrine shale;(iii)the formation experienced lacustrine flooding three times which are meant for lacustrine-basin migration.The deep to semi-deep lacustrine facies was extended into eastern basin during the deposition of Lianggaoshan 1 Member,migrated to central basin during the deposition of Lianggaoshan 2 Member,and developed into north of central basin during the deposition of Lianggaoshan 3 Member;and(iv)both Lianggaoshan 1 and 2 members are the main intervals developed with the deep to semi-deep lacustrine shale.Covering 2.2×10^(4)km^(2),the superimposed shale block is situated in Pingchang-Quxian-Dianjiang area,signifying great potential for shale oil and gas exploration.

关 键 词：四川盆地 早侏罗世 地震相 湖盆迁移 页岩 

分 类 号：P618.13[天文地球—矿床学]