摘要
近年来,四川盆地中二叠统勘探成效显著,是目前勘探开发和研究的热点层位,但其成藏模式、成藏过程与有利勘探区分布尚不明晰。为此,在分析含海泡石层段沉积环境的基础上,修编了中二叠世岩相古地理图,阐述了通江—长寿凹陷控制下的源储配置及成藏模式,明确了中二叠统勘探有利区。研究结果表明:①受古特提斯洋扩张演化、勉略洋俯冲与峨眉大火成岩省构造热事件影响,四川盆地内部中二叠世形成通江—长寿克拉通内凹陷;②在栖霞期沉积时期,沉积相带呈现出北东向和北西向共存的特征,通江—长寿凹陷控制了台内北西向滩体的展布;③到了茅口组二期沉积时期,沉积相带展布主要受通江—长寿凹陷控制,呈现出北西—南东向展布,凹陷两侧边缘滩体发育;④通江—长寿凹陷的发育为中二叠统的源储配置提供了自生自储和旁生侧储两种源储组合新模式;⑤凹陷内海泡石沉积厚度大,大量有机质被吸附,在凉水环境下得到保存,形成优质烃源岩,在埋藏环境中,海泡石开始大量转化与溶解,形成大量有机质孔和黏土微孔,在凹陷内形成自生自储的配置关系,同时海泡石转化释放出的富镁离子的成岩水,通过侧向和垂向运移,将凹陷边缘滩白云石化,形成优质的白云岩储层,形成旁生侧储的配置关系。结论认为,通江—长寿凹陷控制着四川盆地中二叠统油气分布,中二叠统自生自储型非常规泥质灰岩气藏最有利勘探区主要分布在通江—长寿凹陷内,勘探面积约为24800 km^(2),旁生侧储型常规气藏的最有利勘探区主要分布在凹陷两侧边缘带,勘探面积约为47700 km^(2)。
In recent years,the Middle Permian in the Sichuan Basin has achieved significant results in natural gas exploration,and is the current focus horizon of exploration,development and research,but its hydrocarbon accumulation model and process and the distribution of favorable exploration areas have not been clarified.To address these problems,this paper modifies the lithofacies paleographic map of the Middle Permian after analyzing the sedimentary environment of sepiolite bearing strata.Then,the source-reservoir configuration and hydrocarbon accumulation model under the control of Tongjiang-Changshou sag are illustrated,and the favorable exploration areas of the Middle Permian are defined.And the following research results are obtained.First,influenced by the extension evolution of the Paleotethys Ocean,the subduction of the Mianlue Ocean,and the tectonic thermal event of the Emeishan large igneous province,the Tongjiang-Changshou intracratonic sag was formed in the Sichuan Basin during the Middle Permian.Second,during the sedimentation of the Qixia Formation,sedimentary facies belts were of NE and NW trending,and the distribution of the intra-platform NW beach was controlled by the Tongjiang-Changshou sag.Third,during the sedimentation of the second Member of Maokou Formation,the sedimentary facies belts were distributed along the NW-SE direction mainly under the control of the Tongjiang-Changshou sag,and the marginal beaches on both sides of the sag were developed.Fourth,the growth of the Tongjiang-Changshou sag provides two new modes of source-reservoir assemblage(i.e.,self source and self reservoir,and side source and side reservoir)for the source-reservoir configuration of the Middle Permian.Fifth,the sepiolite in the sag is thick,so abundant organic matter is adsorbed and preserved in the cold water environment to form high-quality source rocks.In the burial environment,a large amount of sepiolite is transformed and dissolved to form a great number of organic pores and clay micropores.Thus,the configuration of self-source and selfreservoir is formed in the sag.In the meantime,the magnesium ion rich diagenetic water released during sepiolite transformation dolomitizes the marginal beach of the sag through lateral and vertical migration,forming high-quality dolomite reservoirs.Thus,the configuration of side source and side reservoir is formed.In conclusion,the Tongjiang-Changshou sag controls the distribution of the Middle Permian oil and gas in the Sichuan Basin,and the most favorable exploration area of the Middle Permian unconventional argillaceous limestone gas reservoir of selfsource and self-reservoir type is mainly located in the Tongjiang-Changshou sag,covering an exploration area of about 24800 km^(2),while the most favorable exploration area of the conventional gas reservoir of side source and side reservoir type is mainly distributed in the marginal belts on both sides of the Tongjiang-Changshou sag,covering an exploration area of 47700 km^(2).
作者
宋金民
刘树根
李智武
张本健
邓宾
江青春
金鑫
孙玮
汪华
郭海洋
陈骁
王佳蕊
田小彬
张玺华
叶玥豪
杨迪
范建平
罗平
SONG Jinmin;LIU Shugen;LI Zhiwu;ZHANG Benjian;DENG Bin;JIANG Qingchun;JIN Xin;SUN Wei;WANG Hua;GUO Haiyang;CHEN Xiao;WANG Jiarui;TIAN Xiaobin;ZHANG Xihua;YE Yuehao;YANG Di;FAN Jianping;LUO Ping(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation//Chengdu University of Technology,Chengdu,Sichuan 610059,China;Xihua University,Chengdu,Sichuan 610039,China;PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610051,China;PetroChina Research Institute of Petroleum Exploration&Development,Beijing 100083,China;Southwest Geophysical Prospecting Research Institute of BGP INC.,China National Petroleum Corporation,Chengdu,Sichuan 610036,China;Exploration and Development Research Institute,PetroChina Daqing Oilfield Company,Daqing,Heilongjiang 163712,China)
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2023年第11期54-71,共18页
Natural Gas Industry
基金
国家自然科学基金企业联合创新发展联合基金项目“海相深层油气富集机理与关键工程技术基础研究”(编号:U19B6003)
国家自然科学基金重点项目“青藏高原东缘若尔盖古高原形成与破坏过程及其动力学机制”(编号:42230310)
国家自然科学基金面上项目“川西地区深层雷口坡组微生物岩及其储层形成机理研究”(编号:41872150)。
关键词
四川盆地
中二叠统
通江—长寿凹陷
成藏模式
含海泡石层段
有利勘探区域
Sichuan Basin
Middle Permian
Tongjiang-Changshou sag
Hydrocarbon accumulation model
Sepiolite bearing strata
Favorable exploration area
