四川盆地梓潼—南部地区雷四^(3)亚段天然气成藏地质条件  

Reservoir-forming conditions in T_(2)l_(3)^(4) submember,Zitong-Nanbu area,Sichuan Basin

作　　者：刘辉[1] 战薇芸[1] 叶茂[1] 刘鑫[1] 吴雪峰[1] 孙豪飞[1] 陈尘[1] 潘政屹 张竞月 Liu Hui;Zhan Weiyun;Ye Mao;Liu Xin;Wu Xuefeng;Sun Haofei;Chen Chen;Pan Zhengyi;Zhang Jingyue(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

出　　处：《天然气勘探与开发》2021年第2期19-27,共9页Natural Gas Exploration and Development

基　　金：中国石油西南油气田公司科学研究与技术项目“四川盆地海相碳酸盐岩储量升级评价研究及应用”(编号:20210311-25)。

摘　　要：四川盆地梓潼—南部地区中三叠统雷口坡组四段勘探程度低,勘探尚未取得突破。因此,有必要对该区域开展较为系统的成藏地质条件研究,为下步勘探提供方向。为此,从区域地层划分、沉积相、储层发育分布特征及控制因素、烃源条件、古构造演化等方面开展研究,以期为雷四段天然气扩展勘探提供理论支撑。研究结果表明:①烃源主要来自须一段泥页岩,优质烃源岩分布在其中上部;②研究区位于雷口坡组多期膏质潟湖边缘发育区,以云坪相沉积为主,台内颗粒滩体欠发育;③储层受沉积、岩溶和构造破裂作用的共同控制,纵向多套薄层叠置,横向上有向东逐渐变好的趋势,储层与烃源岩发育"上生下储"和"旁生侧储"两种匹配模式;④区域烃源生烃期、排烃期和气藏调整期均位于须底古构造斜坡区,现今大型构造圈闭和断裂欠发育;⑤构造上倾方向向南膏盐岩侧向封堵、向东储集物性变好、厚度变大,形成大型构造—岩性复合圈闭,成藏条件较好,是下步的有利勘探区。In Zitong-Nanbu area,Sichuan Basin,Leikoupo 4 Member(T_(2)l^(4))hasn’t been deeply explored,and no breakthrough has been made yet.To find some favorable targets for next exploration,it is necessary to systematically study the geological conditions to form natural-gas reservoirs in this area.So,some study was carried out from aspects of regional stratigraphic division,sedimentary facies,reservoir development and distribution,and controlling factors,source-rock conditions,paleo-structural evolution with the intent to provide theoretical support for expanding gas exploration in Leikoupo 4 Member.Results show that,(1)most source rocks mainly originate from the shale in Xujiahe 1 Member,and some high-quality source rocks are distributed at the top shale intervals;(2)the study area,located at multi-stage gypsum lagoon margin of Leikoupo Formation,is dominated by dolomite flat facies and less developed with intra-platform grain bank;(3)controlled by sedimentation,karstification,and tectonic rupture,the reservoirs are thin and stacked vertically,and tend to get better horizontally toward the east.There are two kinds of association containing"top source and bottom reservoir"as well as"one side source and the other reservoir";(4)hydrocarbon generation,expulsion,and accumulation periods happened in the paleo-structural slope at the bottom Xujiahe Formation,but modern large-scale structural traps and faults are less developed;and(5)gypsum-salt rocks seal the south structure at the updip direction,and Leikoupo 4 reservoirs become better in physical properties and larger in thickness toward the east,resulting that a large-scale structural-lithological trap with good reservoir-forming conditions forms,which is favorable for next exploration.

关 键 词：四川盆地 川中—川西过渡带 梓潼—南部地区 雷口坡组 成藏条件 有利勘探区 

分 类 号：P618.13[天文地球—矿床学]