苏里格气田东区马五段储层特征及控制因素

(中国石油长庆分油田勘探开发研究院,陕西 西安 710018)

苏里格气田; 奥陶系; 马五段; 储层特征; 控制因素

Reservoir characteristics and their controlling factors of Ma 5 Member in the Eastern Sulige Gasfield,Ordos Basin
FENG Min,BAI Hui,LIU Zhi-heng,LI Fu-ping,ZHANG Ji

(Cploration Development institute of Changqing Oil field Company,CNPC,Xi'an 710018,China)

Sulige Gasfield; lower Ordovician; Ma 5 member; reservoir characteristics; controlling factors

DOI: 10.13800/j.cnki.xakjdxxb.2019.0216

备注

下奥陶统马家沟组马五1-5段是苏里格气田东区主要产层段,其勘探潜力巨大。基于岩心观察、铸体薄片及分析化验等资料,对马五段进行储层特征及控制因素分析。研究表明,苏里格东区在马五5期为局限台地相带的潮坪亚相沉积。马五1-4为含膏云坪亚相,马五5为颗粒滩相; 发育含膏细-粉晶白云岩和中-粗晶白云岩。苏里格气田东区马五1-5段储集空间包括孔隙和裂缝2大类,其中孔隙主要为溶蚀孔、膏模孔、晶间孔、晶间溶孔和裂缝包括溶蚀缝、微裂缝和构造缝等。储层发育和分布主要受控于:沉积环境决定了多类型储层发育; 马五1-4层段准同生白云石化和渗透回流白云石化及马五5段埋藏白云石化作用是碳酸盐岩储层发育的决定条件,白云石化作用改善了储集性能; 苏里格气田马五1-5层段碳酸盐岩储层经历了不同阶段溶蚀作用(同生、表生、埋藏)而形成有利的溶孔、溶缝储层,提高了储层储集性能。

Ma 5 member of the lower Ordovician Majiagou Formation are main production layers with great exploration potential in the eastern Sulige Gasfield of Ordos Basin.Based on core observation,thin section and experimental analysis material,the reservoir characteristics and their controlling factors are analyzed.The results show that Ma 5 member of the lower Ordovician Majiagou Formation are deposited in tidal flat facies of restricted platform and dolostones are well developed and can be divided into two types: gypsodolomite and mid-macrocrystalline dolomite in the eastern Sulige gasfield.Reservoir space of Ma 5 member can be divided into two types,including dissolved pore,gypsum mould pore,intercrystalline pore,intercrystalline solution pore,dissolution fracture and microfracture etc in the eastern Sulige gasfield.The development and distribution of reservoirs is mainly controlled by the following three aspects:Microfacies are the basis for controlling the development and distribution of different types of reservoirs.Dolomitization of Penecontemporaneous and seepage-reflux in the Ma 51-4 and burial dolomitization of Ma 55 are prerequisites to development of carbonate reservoir,which improve reservoir performance.The carbonate reservoir has gone through several different stages of dissolution,such as syngenetic,supergenetic and burial dissolution,which caused formation of the dissoluted fissures reservoir and improved accumulating space.