川西新场地区中三叠统雷口坡组气藏天然气来源  

Gas source of the Middle Triassic Leikoupo Formation gas reservoir in Xinchang area of western Sichuan Basin,China

作　　者：宋晓波[1,2] 刘勇[1,2] 隆轲[1,2] 何莹[1] 苏成鹏 廖荣峰 蔡左花[1] SONG Xiaobo;LIU Yong;LONG Ke;HE Ying;SU Chengpeng;LIAO Rongfeng;CAI Zuohua(Exploration and Development Research Institute of Southwest Branch Company,SINOPEC,Chengdu 610041,China;Geological Central Lab of Southwest Branch Company,SINOPEC,Chengdu 610081,China)

机构地区：[1]中国石化西南油气分公司勘探开发研究院,四川成都610041 [2]中国石化西南油气分公司地质中心实验室,四川成都610081

出　　处：《天然气地球科学》2024年第12期2121-2131,共11页Natural Gas Geoscience

基　　金：中国石化科技攻关项目“西南探区天然气富集规律与目标评价”(编号:P20059-3)资助。

摘　　要：新场中三叠统雷口坡组气藏是川西地区在新一轮海相油气勘探背景下发现的首个深层海相气藏,多年来,对该气藏气源的认识一直存在争议。利用新一轮钻井的天然气地球化学测试数据,结合油气输导条件梳理,开展了新场雷口坡组四段天然气成因及气源分析。结果表明,新场雷口坡组四段气藏的上、下储层段以及不同构造部位之间在天然气组分与碳氢同位素特征等方面存在一定差异,下储层段较高的H_2S含量可能与其经历相对更强的TSR反应有关,气藏东侧可能存在陆相或海陆过渡相煤成气影响。新场雷口坡组四段气藏中西部的天然气主要表现为海相油型气特征,成熟度相对较高,对应发育“接力式”远源油气输导体系,天然气主要来自二叠系烃源岩,部分来自雷口坡组烃源岩;气藏东北部天然气主要表现为海相与陆相混源气特征,成熟度相对偏低,对应发育雷口坡组顶“棋盘格状”节理网络近源输导体系,天然气主要来自雷口坡组和马鞍塘组—小塘子组烃源岩。It’s the first deep marine gas reservoir discovered in the Middle Triassic Leikoupo Formation in Xin⁃chang area in the latest round of marine hydrocarbon exploration in the western Sichuan Basin.There has been controversy over the understanding of the gas source of this gas reservoir for years.Based on the geochemical da⁃ta of natural gas from the latest round of drilling,combined with hydrocarbon conveyance conditions,the analy⁃sis of the origin and source of natural gas in the fourth member of Leikoupo Formation in Xinchang area was car⁃ried out.The research results indicate that there are differences in natural gas composition and hydrocarbon iso⁃tope characteristics of alkane gas between the upper and lower reservoir sections of the fourth member of Leikou⁃po Formation gas reservoir in Xinchang area,as well as different structural position.The higher H2S content may be related to its relatively strong TSR reaction in the lower reservoir section.The east part of the gas reser⁃voir may have its source from continental or marine-continental coal type gas.The natural gas in the central and western of Xinchang area is mainly characterized by marine oil-type gas with relatively high maturity,corre⁃sponding to the development of relay remote source transport system,indicating that the natural gas mainly come from Permian source rocks,with partly coming from the Leikoupo Formation source rocks;While the nat⁃ural gas in the northeast of Xinchang area is mainly mixed from marine and continental source gases,with rela⁃tively low maturity,corresponding to the development of the near source conveyance system of the orthogonal joint on the top of the Leikoupo Formation,indicating that the natural gas mainly comes from the source rocks of the Leikoupo Formation and Maantang-Xiaotangzi formations.

关 键 词：四川盆地 新场地区 雷口坡组 天然气地球化学 输导体系 气源 

分 类 号：TE122.1[石油与天然气工程—油气勘探]