川中地区金秋气田沙溪庙组致密砂岩有效储集岩石相形成与演化  

Formation and evolution of effective reservoir petrofacies in tight sandstone reservoirs of Shaximiao Formation in Jinqiu Gas Field of Central Sichuan

作　　者：王鸿蒂 罗晓容 王小娟 曹斌风[1] 庞小婷 潘珂 张力升 赵文晟 WANG Hongdi;LUO Xiaorong;WANG Xiaojuan;CAO Binfeng;PANG Xiaoting;PAN Ke;ZHANG Lisheng;ZHAO Wensheng(Department of Geology,Northwest University,State Key Laboratory of Continental Dynamics,Xi’an 710069,China;Research Institute of Exploration and Development,PetroChina Southwest Oil&Gasfield Company,Chengdu 610041,China)

机构地区：[1]西北大学大陆动力学国家重点实验室/地质学系,陕西西安710069 [2]中国石油西南油气田公司勘探开发研究院,四川成都610041

出　　处：《天然气地球科学》2025年第1期127-141,共15页Natural Gas Geoscience

基　　金：国家自然科学基金青年科学基金项目“成岩非均质性对致密砂岩裂缝发育的影响研究”(编号:41902135)资助.

摘　　要：有效储层是致密砂岩油气勘探开发关注的重点之一,整体低渗—致密条件下有效储集空间的形成机制和演化过程是认识有效储层的关键。以川中地区金秋气田沙溪庙组二段为研究对象,综合利用岩石矿物学、电子显微镜(SEM)、碳氧同位素等分析手段,分析储层岩石学和成岩作用特征及差异性,探究有效储集岩石相形成演化过程。针对沙溪庙组二段储层强非均质性的特点,依据岩石学组构、成岩程度与过程、孔隙特征等差异,划分出3种砂岩岩石相。其中,贫塑性颗粒砂岩压实中等,胶结物类型丰富但总量低,溶蚀作用强烈,孔渗性好。富塑性颗粒砂岩和方解石致密胶结砂岩孔渗性较差,前者压实强烈导致岩石致密化,后者因孔隙中大量方解石连晶状胶结致密。原始沉积物组分和结构控制了储层中岩石成岩方式和过程,不同类型岩石相经历了差异化的成岩演化过程。富塑性颗粒砂岩和方解石致密胶结砂岩在成岩早期已变得致密,构成了储层中各个尺度的隔夹层。而贫塑性颗粒砂岩埋藏演化中流体活动及流体—岩石作用多期发生,成岩早期保留了大量原生孔隙,后期流体作用活跃,形成致密储层中孔隙空间较发育、物性较好的有效储集岩石相,该岩石相多分布在分流河道单砂体的中—下部。Effective reservoirs are one of the key points of tight sandstone oil and gas exploration and develop⁃ment,and the mechanism and evolution process of effective reservoir space formation under the overall low per⁃meability to tight condition are the key to understanding effective reservoirs.Taking the second member of the Shaximiao Formation in the Jinqiu Gas Field in central Sichuan as the research object,the characteristics and differences of reservoir petrology and diagenesis were analyzed by comprehensive use of rock mineralogy,elec⁃tron microscopy(SEM),carbon and oxygen isotope analysis methods,and the formation and evolution process of effective reservoir petrofacies was explored.In view of the characteristics of strong heterogeneity of the reser⁃voir in the second member of the Shaximiao Formation,three sandstone petrofacies were divided according to the differences in petrological structure,diagenesis degree and process,and pore characteristics.Among them,permeable reservoir sandstone has medium compaction,rich cementation types but low total amount,strong dissolution and good porosity.The porous permeability of ductile lithic-rich sandstone and tightly carbonate-ce⁃mented sandstone is poor,the former is strongly compacted and leads to rock densification,and the latter is dense due to a large amount of calcite crystalline cementation in the pores.The composition and structure of the original sediments control the diagenesis of the rocks in the reservoir,and different types of petrofacies have un⁃dergone different diagenetic evolution.The ductile lithic-rich sandstone and tightly carbonate-cemented sand⁃stone have become dense in the early diagenetic stage,constituting interlayers of various scales in the reservoir,while the fluid activity and fluid-rock interaction occurred in the buried evolution of the permeable reservoir sand⁃stone,and a large number of primary pores were retained in the early diagenetic stage,and the fluid action was active in the later stage,forming an effective reserv

关 键 词：成岩作用 非均质性 有效储层 岩石相 致密砂岩储层 

分 类 号：TE122.23[石油与天然气工程—油气勘探]