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

作　　者：王波[1] 宋光永 张荣虎 曾庆鲁 王艳清 孙秀建[3] 吴志雄[1] 李森明 李雅楠 宫清顺 WANG Bo;SONG Guangyong;ZHANG Ronghu;ZENG Qinglu;WANG Yanqing;SUN Xiujian;WU Zhixiong;LI Senming;LI Yanan;GONG Qingshun(PetroChina Qinghai Oilfield Company;PetroChina Hangzhou Research Institute of Geology;Northwest Branch of PetroChina Research Institute of Petroleum Exploration&Development)

机构地区：[1]中国石油青海油田公司,甘肃省酒泉市736202 [2]中国石油杭州地质研究院,浙江省杭州市310023 [3]中国石油勘探开发研究院西北分院

出　　处：《海相油气地质》2025年第1期59-70,共12页Marine Origin Petroleum Geology

基　　金：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。

摘　　要：在大量岩心、铸体薄片、扫描电镜、X衍射全岩矿物、测井等资料分析的基础上,系统研究了柴北缘超深层(深度超过7000 m)基岩油气藏的储层主控因素及成藏条件。研究表明:①中酸性花岗质基岩作为储层的优质岩性,在多期变质、构造成缝、风化剥蚀等有利成储因素的耦合效应下,形成以裂缝及溶蚀孔为主要储集空间且受埋藏压实影响小的风化壳与内幕2类成因的有效储层;②侏罗系碳质泥岩(亦是烃源岩)与古近系路乐河组膏质泥岩2套有效盖层为油气长距离运移和有效聚集创造了条件;③生烃期与输导断层及圈闭形成期同步是油气富集成藏的关键因素;④主要分布于凹陷区的侏罗系高成熟煤型气源岩与下伏基岩储层构成侧接式上生下储源储组合,并以断层和基岩顶部的不整合面为烃类运移通道,形成源外、源内2类油气藏。受接替式油气运移机制及盖层条件控制,形成构造高部位聚集石油且充满度与丰度低,构造中—低部位聚集天然气且充满度与丰度高的成藏特点。认为柴北缘超深层基岩具备较大的油气勘探潜力。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 7000 m)reservoirs in the northern Qaidam Basin.The specific findings are as follows:(1)Intermediate-acidic granitic bedrocks serve as highquality 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 longdistance 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

关 键 词：超深层 基岩 储层特征 成藏条件 柴达木盆地 

分 类 号：TE122.3[石油与天然气工程—油气勘探]