石油勘探与开发2025，Vol.52Issue(2)：374-384,11.DOI:10.11698/PED.20240289
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
摘要
Abstract
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 H2S and CO2 contents,with an elevated δ13C2 value(average value higher than-29‰).The Dengying gas reservoirs in the Weiyuan area are less affected by TSR modification,though the δ13C1 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,theδ2HCH4 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 to the Cambrian Qiongzhusi Formation.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Key words
thermochemical sulfate reduction(TSR)/Well Datan-1/helium-rich gas reservoir/Sinian Dengying Formation/Deyang-Anyue rift trough/Sichuan Basin分类
石油、天然气工程引用本文复制引用
宋泽章,陶佳丽,何家欢,李文正,葛冰飞,王冠,高嘉玮,金世贵,罗冰,罗情勇,田兴旺,杨岱林,张子羽,张文锦,武鲁亚..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[J].石油勘探与开发,2025,52(2):374-384,11.基金项目
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) （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) （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) （2024D101-01-06）
