松辽盆地北部中央古隆起基岩气藏形成条件与有利勘探区  

Favorable exploration area and formation condition of bedrock reservoir in the of central paleo-uplift,northern Songliao Basin

作　　者：冉逸轩 王健[1] 张熠 RAN Yixuan;WANG Jian;ZHANG Yi(School of Geosciences,China University of Petroleum(East China),Qingdao 266580,Shandong,China;Exploration and Production Research Institute,Daqing Oilfield,Daqing 163712,Heilongjiang,China)

机构地区：[1]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [2]大庆油田勘探开发研究院,黑龙江大庆163712

出　　处：《岩性油气藏》2024年第6期66-76,共11页Lithologic Reservoirs

基　　金：国家科技重大专项“松辽盆地致密油开发示范工程”(编号:2017ZX0071)资助。

摘　　要：为寻找松辽盆地中央古隆起基岩天然气富集区,分析了其天然气成因和有利成藏条件,优选了基岩气藏有利勘探区块。研究结果表明:①松辽盆地北部中央古隆起天然气组分和成因与徐家围子断陷类似,均是以甲烷为主的高—过成熟的煤型气,显示基岩气藏气源主要来自古隆起东侧徐家围子断陷。②优质烃源岩、有利储层、立体输导通道和优良盖层等有利条件耦合是形成基岩气藏的关键,沙河子组烃源岩泥岩和煤岩TOC平均分别为4.33%和32.56%,处于高过成熟阶段,宋站和徐西等生烃洼槽生烃强度普遍大于180×10^(8)m^(3)/km^(2),是基岩重要的气源;受风化和破裂作用影响,基岩顶、底形成的风化壳孔缝层、内幕裂缝层等有利储层孔隙度分别为4.3%和1.3%,渗透率分别为0.45 mD和6.3 mD;风化壳、断层和裂缝耦合形成“S”型、“T”型和“断缝体”型输导通道,促进了天然气的侧向运移;登娄库组泥岩厚度大、突破压力高,且其形成时间早于天然气大规模运移和充注成藏期,使得基岩气藏得以保存。③中央古隆起带可分为3个有利勘探区,北部汪家屯凸起和昌德凸起主要为风化壳气藏,发育“S”型、“T”型输导通道,气藏受输导通道和保存条件联合控制,南部肇州凸起则以基岩内幕气藏为主,发育“断缝体”型输导通道,气藏受储层厚度、物性和圈闭影响明显。The favorable area of bedrock gas exploration in the central paleo-uplift of Songliao Basin was selected on the basis of genesis and formation condition analysis,in order to find the gas accumulation areas.The result shows that:(1)The gas composition and genesis in the central paleo-uplift of northern Songliao Basin is similar to Xujiaweizi fault depression.They are all coal-type gas formed in high and over mature stage,indicate that the gas in the central paleo-uplift is come from the Xujiaweizi fault depression.(2)The union of formation condition such as favorable source rock,favorable reservoir,transport system and favorable cap are the key factors for bedrock reservoir.The TOC of source rocks of Shahezi Formation mudstone and coal is 4.33%and 32.56%,which are in mature to high state.The hydrocarbon generation intensity in Songzhan sag and Xuxi sag is greater than 180×10^(8)m^(3)/km^(2),which is main gas source for the bedrock reservoirs.The pore layer on top of weathering crust and fracture layer in bottom of inner bedrock are the favorable reservoirs,which are formed by"weathering+fracture",with a porosity of 4.3%and 1.3%,and permeability of 0.45 mD and 6.3 mD.There are“S”type,“T”type and“fault-fracture”transport channels coupled by the crust of weathering,fault and fracture,promote the natural gas migration in lateral.The mudstone of Denglouku Formation formed early than gas migration,which is characteristic by great thickness and high breakthrough pressure,due to the preservation of gas reservoirs.(3)Central paleo-uplift can be divided to three favorable exploration areas.The gas in Wangjiatun and Changde bulge are mainly crust of weathering,with a“S”type and“T”type transport channel.The gas are control by the union of transport channel and preservation condition.The gas in Zhaozhou bulge are bedrock gas reservoir,with a transport channel of“fault-fracture”body,which is under controlled by reservoir thickness,quality and trapes.

关 键 词：基岩气藏 成藏条件 风化壳孔缝层 内幕裂缝层 内幕致密层 沙河子组烃源岩 中央古隆起 松辽盆地北部 

分 类 号：TE122.3[石油与天然气工程—油气勘探] P618.13[天文地球—矿床学]