天然气工业2025，Vol.45Issue(11)：69-82,14.DOI:10.3787/j.issn.1000-0976.2025.11.006
柴达木盆地北缘下侏罗统煤系砂岩储层发育机制与天然气勘探方向
Development mechanism and natural gas exploration direction of Lower Jurassic coal-measure sandstone reservoirs in the northern margin of the Qaidam Basin
摘要
Abstract
The development degree of deep and ultra-deep Lower Jurassic coal-measure sandstone reservoirs in the northern margin of the Qaidam Basin is a key geological issue faced by natural gas exploration in this are-a.However,there is less research on the reservoir-controllinge mechanism,and the understanding on reservoir development characteristics cannot meet the needs of deep and ultra-deep natural gas exploration and development.Therefore,it is in urgent need to research the formation mechanism of Jurassic coal-measure sandstone reservoirs.Based on the cast thin section analysis,combined with the basic testing and analysis data of whole-rock mineral,porosity,permeability,seismic and logging,this paper systematically analyzes the characteristics of the Lower Jurassic coal-measure sandstone reservoirs in the northern margin of the Qaidam Basin,clarifies the formation mechanism and development characteristics of reservoirs,and points out the exploration direcction of deep and ultra-deep natural gas.The following results are obtained.First,the reservoir space in the Lower Jurassic coal-meatsutre sandstone is dominated by secondary dissolution pores,and the dissolution intensity is a key factor affecting the development of quality coal-measure sand-stone reservoirs.Second,the distance frrom the unconformity surface at the top of the Maesozoict ctontrols the vertical distributioon of quality csoal-smeasure sanodstone reservoirs.Third,three sets of reiservoir intervals ae identified vertically in the Lower Jurassic coal-measure sandstone.The first reservoir interval is distributed within 100 m from the unconformity surface at the top of the Mesozoic,where the leaching and dissolution of atmospheric water is the main controlling factor,and medium-porosity and low-permeability reservoirs are developed;the second one is distributed at a distance of approximately 100-1 000 mfrom the unconformity surface at the top of the Mesozoic,where the dissolution of humic acid is the main controlling factor,and low-porosity and extra low-permeability reservoirs are developed;the third one is more than 1 000 m far from the unconformity surface at the top of the Mesozoic,where the dissolution of organic acid is tne main controlling factor,and ultra-low porosity and ultra-low permeability reservoirs are developed.In conclusion,dissolution-type reservoirs are widely developed in the coal-measure sandstone,and their physical properties have no obvious correlation with the current burial depth,but are closely related to the distance from the unconformity surface at the top of the Mesozoic.The first and second reservoir intervals have better physical properties,while the third one is relatively dense,but all of them can serve as effective reservoirs of natural gas.What's more,the proposal that"the distance from the unconformity surface at the top of the Mesozoic"controls the vertical distribution of reservoirs is of great guidance significance to the exploration of deep and ultra-deep natural gas in the Qaidam Basin.关键词
柴达木盆地/深层—超深层/下侏罗统/煤系砂岩/不整合面/控制因素/天然气勘探方向Key words
Qaidam Basin/Deep and ultra-deep strata/Lower Jurassic/Coal-measure sandstone/Unconformity surface/Control factor/Natural gas exploration direction分类
能源科技引用本文复制引用
王波,徐帆,王艳清,周飞,朱超,宋光永,刘占国,石正灏,宫清顺,裴梓薇..柴达木盆地北缘下侏罗统煤系砂岩储层发育机制与天然气勘探方向[J].天然气工业,2025,45(11):69-82,14.基金项目
新型油气勘探开发国家科技重大专项项目"柴达木盆地盆山体系油气成藏机制与新领域勘探技术"(编号:2025ZD1400600)、中国石油天然气股份有限公司科技专项项目"超深层碎屑岩大中型油气田形成条件与有利区评价"(编号:2023ZZ14YJ01). （编号:2025ZD1400600）
