四川盆地德阳-安岳裂陷槽东西两侧震旦系灯影组天然气地球化学特征差异及其成因  

Geochemical differences in natural gas of Sinian Dengying Formation on the east and west sides of the Deyang-Anyue rift trough and their genesis,Sichuan Basin,SW China

作　　者：宋泽章 金世贵 罗冰[3] 罗情勇 田兴旺 杨岱林[3] 张子羽 张文锦 武鲁亚 陶佳丽 何家欢[3] 李文正[4] 葛冰飞 王冠 高嘉玮[1,2] SONG Zezhang;JIN Shigui;LUO Bing;LUO Qingyong;TIAN Xingwang;YANG Dailin;ZHANG Ziyu;ZHANG Wenjin;WU Luya;TAO Jiali;HE Jiahuan;LI Wenzheng;GE Bingfei;WANG Guan;GAO Jiawei(National Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum(Beijing),Beijing 102249,China;College of Geosciences,China University of Petroleum(Beijing),Beijing 102249,China;Exploration and Development Research Institute of PetroChina Southwest Oil&Gas Field Company,Chengdu 610051,China;PetroChina Hangzhou Research Institute of Geology,Hangzhou 310023,China)

机构地区：[1]油气资源与工程全国重点实验室,中国石油大学(北京),北京102249 [2]中国石油大学(北京)地球科学学院,北京102249 [3]中国石油西南油气田公司勘探开发研究院,成都610051 [4]中国石油杭州地质研究院,杭州310023

出　　处：《石油勘探与开发》2025年第2期374-384,共11页Petroleum Exploration and Development

基　　金：国家自然科学基金面上基金项目“深层、超深层热液活动及其对古油藏改造效应定量表征”(42272161);中国石油天然气股份有限公司重大科技专项“海相碳酸盐岩油气规模增储上产与勘探开发技术研究”(2023ZZ16);中国石油天然气股份有限公司西南油气田公司勘探开发研究院“四川盆地Xai源岩特征及富Xai潜力评价实验研究”(2024D101-01-06)。

摘　　要：以四川盆地德阳—安岳裂陷槽两侧(裂陷东侧高石梯—磨溪地区和川中古隆起北斜坡;裂陷西侧威远地区和大探1井区)震旦系灯影组天然气藏为研究对象,在充分对比不同地区灯影组天然气地球化学参数(组分、同位素组成)的基础上,明确裂陷槽两侧灯影组天然气地球化学特征差异及其成因。研究表明:①裂陷槽两侧灯影组气藏以原油裂解气为主,成熟度高,为典型的干气;②受较强的硫酸盐热化学还原反应(TSR)改造,裂陷东侧灯影组气藏的H_(2)S、CO_(2)含量高,δ^(13)C_(2)偏重(平均值大于−29‰);威远地区灯影组气藏受TSR影响小,遵循水溶气析出成藏模式,δ^(13)C_(1)较裂陷东侧稍重,部分碳同位素组成发生倒转;大探1井灯影组气藏基本不受TSR影响;③裂陷西侧大探1井区及威远地区基底花岗岩广泛发育且断裂垂向输导高效,灯影组气藏He含量显著高于裂陷东侧;④受烃源岩沉积期的古水介质盐度控制,裂陷西侧灯影组气藏的δ^(2)H_(CH4)较东侧稍轻;⑤大探1井区灯影组天然气除了来自寒武系筇竹寺组烃源岩外,还有震旦系灯影组三段及陡山沱组烃源岩的贡献。Taking the natural gas reservoirs of the Sinian Dengying Formation on the east and west sides(Gaoshiti-Moxi area and north slope of central Sichuan paleo-uplift on the east;Weiyuan and Well Datan-1 block on the west)of the Deyang-Anyue rift trough in the Sichuan Basin,China,as the research object,the geochemical parameters(component,isotopic composition)of natural gas from the Dengying Formation in different areas are compared,and then the differences in geochemical characteristics of Dengying natural gas on the east and west sides of the Deyang-Anyue rift trough and their genesis are clarified.First,the Dengying gas reservoirs on both sides of the rift trough are predominantly composed of oil-cracking gas with high maturity,which is typical dry gas.Second,severely modified by thermochemical sulfate reduction(TSR)reaction,the Dengying gas reservoirs on the east side exhibit high H_(2)S and CO_(2) contents,with an elevatedδ^(13)C_(2) value(average value higher than-29‰).The Dengying gas reservoirs in the Weiyuan area are less affected by TSR modification,though theδ^(13)C_(1) values are slightly greater than that of the reservoirs on the east side with partial reversal of carbon isotope composition,likely due to the water-soluble gas precipitation and accumulation mechanism.The Dengying gas reservoir of Well Datan-1 shows no influence from TSR.Third,the Dengying gas reservoirs reflect high helium contents(significantly higher than that on the east side)in the Weiyuan and Datan-1 areas on the west side,which is supposed to attribute to the widespread granites in basement and efficient vertical transport along faults.Fourth,controlled by the paleo-salinity of water medium in the depositional period of the source rock,theδ^(2)H_(CH4) values of the Dengying gas reservoirs on the west side are slightly lighter than those on the east side.Fifth,the Dengying natural gas in the Datan-1 area is contributed by the source rocks of the Sinian Doushantuo Formation and the third member of the Dengying Formation,in addition

关 键 词：硫酸盐热化学还原反应(TSR) 大探1井 富氦气藏 震旦系灯影组 德阳—安岳裂陷槽 四川盆地 

分 类 号：TE122.1[石油与天然气工程—油气勘探]