摘要
为明确鄂尔多斯盆地杭锦旗地区不同区带天然气特征及来源上的差异,通过天然气气体组分分析和碳同位素分析等手段,对杭锦旗地区3个主要勘探区带天然气地球化学组成特征进行了详细的对比剖析,并结合各区带天然气在成藏过程中的差异,对其来源进行了分析探讨。研究区天然气烃类气体含量较高(以甲烷为主),干燥系数多低于0.95,整体呈现出湿气特征,非烃类气体主要为二氧化碳和氮气,含量较低;天然气碳同位素δ^(13)C_(1)、δ^(13)C_(2)和δ^(13)C_(3)组成表现为正碳序列分布,但不同区带天然气碳同位素组成之间存在着差异,其中什股壕区带天然气δ^(13)C_(1)值最重,而新召区带天然气δ^(13)C_(2)和δ^(13)C_(3)值要明显重于其他2个区带。成因分析结果表明,研究区3个区带天然气均为有机成因气,呈现出煤型气(腐殖型气)的特征,主体为干酪根初次裂解气,且其气源岩处于高成熟—过成熟热演化阶段。结合气源对比结果与地质背景,推测新召区带天然气主要由下伏山西组烃源岩供烃,独贵加汗和什股壕区带天然气则来源于断裂南部太原组和山西组烃源岩的共同贡献,但前者太原组烃源岩贡献比例相对更高。
In order to clarify the differences of characteristics and sources of natural gas in different zones in Hangjinqi area of Ordos Basin,the geochemical composition characteristics of natural gas in three major exploration zones in Hangjinqi area were compared and analyzed in detail by means of gas composition analysis and carbon isotope analysis,and sources of natural gas in different zones were discussed based on the differences in the process of gas accumulation in different zones.The results show that the natural gas of the study area has a high content of hydrocarbon gases(mainly methane),and the drying coefficients are mostly lower than 0.95,suggest-ing that the natural gas is dominated by wet gases.The non-hydrocarbon gases are mainly carbon dioxide and nitrogen,which have lower contents.The carbon isotopes δ^(13)C_(1),δ^(13)C_(2) and δ^(13)C_(3) of natural gas show a positive carbon series distribution,but there are differences among natural gas carbon isotopes compositions in different zones.The δ^(13)C_(1) value of natural gas in Shiguhao zone is the heaviest,and the δ^(13)C_(2) and δ^(13)C_(3) values of natural gas in Xinzhao zone are significantly heavier than that in the other two zones.The genetic analysis results show that the natural gas in the three regions of the study area is of organic genesis,showing the characteristics of coal-type gas(humus-type gas),and the main body is kerogen primary cracking gas,and the source rocks are in the stage of high-mature to over-mature thermal evolution.Combined with the results of gas-source correlation and geological background,it is inferred that the natural gas in Xinzhao zone is mainly derived from the underlying source rocks of Shanxi Formation,and the natural gas in Duguijiahan and Shiguhao zones is sourced from the source rocks of Taiyuan and Shanxi formations in the southern part of the fault,but Taiyuan source rocks contribute more.
作者
张迈
宋到福
王铁冠
何发岐
张威
安川
刘悦
陆振港
ZHANG Mai;SONG Daofu;WANG Tieguan;HE Faqi;ZHANG Wei;AN Chuan;LIU Yue;LU Zhengang(National Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum(Beijing),Beijing 102249,China;North China Company,SINOPEC,Zhengzhou,Henan 450000,China)
出处
《石油实验地质》
CAS
CSCD
北大核心
2024年第1期124-135,共12页
Petroleum Geology & Experiment
基金
国家重点研发计划项目“富氦天然气成藏机制及氦资源分布预测技术”(2021YFA0719000)资助。
作者简介
张迈(1995-),男,博士生,从事有机地球化学、油藏地球化学等方面的研究。E-mail:zhangmai2024@163.com;通信作者:宋到福(1983-),男,博士,副教授,从事有机地球化学、油藏地球化学等方面的研究。E-mail:songdaofu2008@163.com。
