河坝区块嘉二气藏储层特征及控制因素

四川盆地北部河坝区块嘉二气藏A201H井、A202H井相继获得197×104,136×104 m3/d的无阻流量,揭示该区嘉二气藏具有巨大的勘探开发潜力。综合岩心观察、薄片鉴定、压汞、测井等多种资料,对储层的基本特征及主控因素进行分析。结果表明,储层储集空间主要为残余原生粒间孔、晶间(溶)孔及粒内溶孔;喉道以片状为主,孔喉连通性较差,孔隙结构复杂;物性差,表现为特低孔致密储层的特征。储层发育受沉积及成岩作用控制,其中,微古地貌高点发育的砂屑滩是储层形成的物质基础;短暂暴露的岩溶作用及白云石化作用是储层形成的关键因素;初期压实与浅埋藏胶结充填部分孔隙是储层致密化的关键因素;裂缝性重结晶及埋藏溶蚀作用优化改造砂屑滩储层,是优质储层发育的关键因素。

Characteristics and controlling factors of the gas reservoirs in the second member of Jialingjiang formation in Heba block

In Heba block of the northern Sichuan basin, A201 H and A202 H wells successively obtained open flow capacity of 197 × 10~4, 136 × 10~4 m~3/d, which reveal that the gas reservoir from the second member of Jialingjiang formation has great exploration and development potential. Based on core observation, thin section identification, mercury injection, logging and other data, the basic characteristics and main controlling factors of the reservoir were analyzed. The results show that the reservoir space is mainly of residual primary intergranular pores, intergranular(dissolved) pores and intra granular dissolved pores; the throat is mainly of flaky, with poor connectivity and complex pore structure; the physical property is poor, showing the characteristics of ultra-low porosity tight reservoir. The reservoir development is controlled by sedimentation and diagenesis, and the sand chip beach developed at the high point of micro paleogeomorphology is the material basis of reservoir formation. Transient exposure of karst and dolomitization is the key factor of reservoir formation, initial compaction and part of pores with shallow buried cementation filling are the key factors of reservoir densification, and fracture recrystallization and buried dissolution are the key factors of high quality reservoir development.