摘要
以岩芯及野外观察、分析测试、测井等资料为基础,分析了川东北巴中-通南巴地区致密砂岩储层裂缝的类型及成因,结合裂缝充填矿物包裹体分析,厘定裂缝形成期次。在此基础上,探讨了岩性组合、岩层厚度、断层、褶皱变形强度对裂缝发育的控制作用。研究表明:研究区须家河组裂缝具有多成因、多期次、差异分布的特点。主要发育构造裂缝,且主要分布于致密砂岩储层中,可划分为3期:燕山中期(中侏罗世)的NNW和NWW向共轭构造缝,被细粒方解石充填;燕山晚期(白垩纪)的NE向断层、褶皱伴生高角度缝,被粗粒方解石或石英充填;喜马拉雅期(古近纪)的NW和近SN向断层伴生缝,被粗粒方解石半充填或未充填。成岩裂缝和超压裂缝的成因与黏土矿物失水收缩及烃源岩大量生烃引起的流体增压有关,主要形成时间为晚侏罗世-早白垩世。裂缝发育的差异性主要受控于岩性组合、地层厚度、断层及褶皱变形强度,单层厚度小、距断层距离近、褶皱变形强度大的中、细砂岩储层,裂缝最为发育。
The types and the causes of fractures in the Xujiahe Formation tight sandstone reservoir,in the Bazhong-Tongnanba area of northeastern Sichuan basin,were studied based on the core and outcrop observations,analysis and testing,loggings and other data which was combined with inclusion analysis to identify the fracture formation stages.Based on this,the relative control of lithology combination,stratum thickness,fault and fold deformation strength on fracture development is discussed.The results show that the fractures of the Xujiahe Formation in the northeastern Sichuan Basin were triggered by various causes,formed in multiple stages,and show differential distribution.Tectonic fractures,mainly developed and distributed in tight sandstone reservoirs,can be divided into 3 stages:the NNW and NWW directional tectonic fractures in the middle Yanshanian(Middle Jurassic),and filled by fine-grained calcite;the NE trending fractures associated with fault and fold were formed in the late period of Yanshan movement and were filled with quartz and coarse calcite;and the NW and SN trending fractures associated with fault were formed in the early period of Himalaya tectonic movement,and are either empty or partially filled with coarse grained calcite.The diagenetic fractures and overpressure fractures are related either to water shrinkage of clay minerals or the fluid pressurization caused by massive hydrocarbon generation in source rocks and formed in Late Jurassic-Early Cretaceous.The development of fractures is mainly affected by lithology combination,stratum thickness,fault and fold deformation strength.The middle and fine sandstone reservoirs with small stratum thickness,closer location to fault,and greater strength of fold deformation have developed more fractures.
作者
蒋有录
李明阳
王良军
刘景东
曾韬
赵承锦
JIANG Youlu;LI Mingyang;WANG Liangjun;LIU Jingdong;ZENG Tao;ZHAO Chengjin(School of Geosciences China University of Petroleum(East China),Qingdao,Shandong,266580;Sinopec Exploration Company,Chengdu,Sichuan,610041)
出处
《地质学报》
EI
CAS
CSCD
北大核心
2020年第5期1525-1537,共13页
Acta Geologica Sinica
基金
国家科技重大专项“四川盆地碎屑岩层系油气富集规律与勘探评价”项目(编号2016ZX05002004)资助成果。
关键词
四川盆地
巴中-通南巴地区
须家河组
裂缝特征
形成期次
控制因素
Sichuan basin
Bazhong-Tongnanba area
Xujiahe Formation
fracture characteristics
formation stages
controlling factors
