海相油气地质2025，Vol.30Issue(1)：59-70,12.DOI:10.3969/j.issn.1672-9854.2025.01.005
柴达木盆地超深层基岩气藏勘探发现及启示
Discovery and geological significance of ultra-deep bedrock gas reservoirs in the Qaidam Basin
摘要
Abstract
Based on analysis of a large number of core samples,thin sections,scanning electron microscopy,X-ray diffraction of whole-rock minerals,and well logging data,a systematic study is conducted on the favorable geological factors and conditions for hydrocarbon accumulation in the bedrock(at depths exceeding 7 000 m)reservoirs in the northern Qaidam Basin.The specific findings are as follows:(1)Intermediate-acidic granitic bedrocks serve as high-quality reservoir lithologies.Under the coupled effects of multiple phases of metamorphism,tectonic fracturing,weathering and erosion,and other favorable reservoir-forming factors,two genetically distinct effective reservoirs have formed:weathering crust and interior reservoirs,with fractures and dissolution pores as the main storage spaces and minimal impact from burial compaction.(2)Two effective sealing layers,namely Jurassic carbonaceous mudstones(which are also source rocks)and Paleogene Lulehe Formation gypsiferous mudstones,provide condition for long-distance hydrocarbon migration and effective accumulation.(3)The synchronization of hydrocarbon generation periods with conductive faults and trap formation periods offers excellent conditions for hydrocarbon enrichment and reservoir formation.(4)The Jurassic high-maturity coal measure gas source rocks,primarily distributing in the depression area and overlying the bedrocks,form a laterally adjacent source-reservoir association with the bedrock reservoirs,with faults and the unconformity at the top of the bedrock serving as hydrocarbon migration pathways,resulting in two types of hydrocarbon reservoirs:extra-source and intra-source.Controlled by differential or successive hydrocarbon migration mechanisms,the reservoirs exhibit characteristics of oil accumulation at structurally high positions with low fullness and abundance,and gas accumulation at structurally medium to low positions with high fullness and abundance.The research indicates that the ultra-deep bedrocks still hold significant potential for hydrocarbon exploration.The analysis of the favorable conditions for hydrocarbon accumulation and their spatiotemporal configuration in these ultra-deep bedrocks can provide target areas for hydrocarbon exploration in this region and also contribute to a deeper understanding of the reservoir-forming and hydrocarbon accumulation processes in deep to ultra-deep bedrocks.关键词
超深层/基岩/储层特征/成藏条件/柴达木盆地Key words
ultra-deep/bedrock/reservoir characteristics/conditions for hydrocarbon accumulation/Qaidam Basin分类
石油、天然气工程引用本文复制引用
王波,宫清顺,宋光永,张荣虎,曾庆鲁,王艳清,孙秀建,吴志雄,李森明,李雅楠..柴达木盆地超深层基岩气藏勘探发现及启示[J].海相油气地质,2025,30(1):59-70,12.基金项目
本文受中国石油天然气股份有限公司重大科技专项"叠合盆地中下组合规模储层形成机制与分布规律研究"(编号:2023ZZ0204)资助 （编号:2023ZZ0204）
