苏里格气田下古生界储层特征及主控因素

Characteristics and controlling factors of Lower Paleozoic reservoir in Sulige Gas Field

苏里格气田下古生界马家沟组储层目前已成为该气田稳产的有力支撑,分析其储层特征及控制因素对维持气田稳产具有重大意义。利用岩心观察、薄片鉴定、阴极发光等资料,系统分析了马家沟组主力储层特征。研究表明:马家沟组储层以颗粒白云岩、晶粒白云岩和微生物岩为主,储集空间主要为晶间孔、晶间溶孔、膏模孔、小型溶蚀孔洞及粒间孔等;储层展布主要受控于岩溶作用及古地貌分布,加里东期表生岩溶作用对储层改善贡献不大,甚至是一种破坏作用;岩溶古地貌高部位主要受表生岩溶作用的影响,对储层的储集空间和连通性有一定的改造作用,使储层物性较好,单井产气量高,而岩溶古地貌低部位主要受准同生期岩溶作用的影响,物性相对较差,单井产气量低。该研究成果可为苏里格气田下古生界气藏的有利区预测提供地质依据。

The reservoir of Lower Paleozoic Majiagou Formation in Sulige Gas Field has become a strong support for stable production of the gas field.It is of great significance to analyze the reservoir characteristics and control factors for maintaining stable production of the gas field.The main reservoir characteristics of Majiagou Formation were analyzed by means of core observation,thin section identification and cathodoluminescence.The results show that the reservoir of Majiagou Formation is mainly granular crystalline dolomite,grain crystalline dolomite and microbiological rock.The reservoir pores are mainly intercrystalline pore,intercrystalline dissolved pore,gypsum mould pore,miniature dissolved holes,intergranular pores.Reservoir distribution is mainly controlled by karstification and paleogeomorphic distribution.Epidiagenetic karstification in the Caledonian period has little contribution to the reservoir,even a destructive effect.The high part of karst palaeogeomorphology is mainly affected by epidiagenetic karstification,which has a certain transformation effect on the reservoir space and connectivity,resulting in better reservoir physical properties and high gas production per well,while the low part of karst palaeogeomorphology is mainly affected by the karstification in the quasi-contemporaneous period,with relatively poor physical properties and low gas production per well.The research results can provide geological basis for the prediction of favorable areas of Lower Paleozoic gas reservoirs in Sulige Gas Field.