摘要
塔里木台盆区下古生界海相碳酸盐岩地层是我国深层油气勘探的热点领域,但深层-超深层天然气的成因来源判识及成藏过程分析至今仍是天然气地球科学的难点问题。本次研究对塔里木台盆区下古生界天然气的组分及同位素组成进行了测定,结合前人研究成果及地质条件,认为甲烷氢同位素组成(δ^(2)H_(1))是研究区更可信的成熟度评价指标,并建立了利用δ^(2)H_(1)值、烷烃气碳同位素值及干燥系数讨论天然气成因来源、生气机理及次生作用的新模式。研究表明:塔里木台盆区下古生界富集了由不同热演化程度、不同成因类型和不同地球化学组成特征的烃源岩生成的天然气,且大部分天然气藏来源于相对开放的生烃系统的贡献,原油裂解气的贡献相对较低,但受控于碳酸盐岩储层和疏导体系发育的强非均质性,也有部分天然气藏来源于相对封闭的生烃环境且具有较高的原油裂解气的贡献。这些成因来源复杂多样的天然气在运聚成藏过程中还发生了以混合和氧化蚀变为主的次生改造作用。
The Lower Paleozoic marine carbonate strata of the cratonic platform area,Tarim Basin are a deep oil and gas exploration hotspot in China.However,the origin of deep and ultra-deep natural gases and their accumulation process are still difficult problems in natural gas geoscience.In this study,the chemical and isotopic compositions of natural gases in the Lower Paleozoic were determined.Combined with previous results and regional geology we believe the hydrogen isotopic composition of methane(δ^(2)H_(1))is a more reliable maturity indicator for source rocks in the study area,and a new way of discussing the origin,generation mechanism and secondary alterations of natural gas reservoirs is established using δ^(2)H_(1) value,δ^(13)C values of alkane gases and gas dryness coefficient.The Lower Paleozoic accumulated gaseous hydrocarbons generated from source rocks of different maturities,genetic types and geochemical characteristics.Moreover,most of the natural gas reservoirs were formed under relatively open environments,with low contribution of oil cracking gases.Nevertheless,there are also some natural gas reservoirs formed under relatively closed environments that received large amounts of oil-cracking gases due to high heterogeneity in carbonate reservoirs and transport systems,where natural gases of complex,diverse origins have undergone secondary transformations,mainly mixing and oxidative alteration,during the accumulation process.
作者
陈泽亚
陈践发
黎茂稳
付娆
师肖飞
徐学敏
伍建军
CHEN Zeya;CHEN Jianfa;LI Maowen;FU Rao;SHI Xiaofei;XU Xuemin;WU Jianjun(PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083,China;State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum(Beijing),Beijing 102249,China;Petroleum Exploration and Production Research Institute,SINOPEC,Beijing 102206,China;CNOOC Central Laboratory(Shanghai),CNOOC EnerTech-Drilling and Production Co.,Shanghai 200941,China;National Research Center for Geoanalysis,Beijing 100037,China;PetroChina Tarim Oilfield Company,Korla 841000,China)
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2023年第6期232-246,共15页
Earth Science Frontiers
基金
国家自然科学基金企业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(U19B6003)”。
关键词
塔里木盆地
下古生界
氢同位素
成因来源判识
次生作用
Tarim Basin
Lower Paleozoic
hydrogen isotope
genetic identification
secondary alteration
