Research On The Characteristics Of Ordovician Carbonate Reservoir In The Shunbei Area Of The Tarim Basin

The area of Shunbei is located at the shallow uplift of Shuntuoguole which is bounded by the Awati depression to the west and the Manjar sag to the east in the midwest of the Tarim Basin.Guided by theories such as petroleum geology,petrology,structural geology and geophysics,this study,mainly explores the sedimentary facies,sequence strata,characteristics,main controlling factors and development models of Ordovician carbonatite reservoir in the Shunbei Area.The sedimentary and diagenetic characteristics of carbonatite are revealed;a three-level sequence stratigraphic framework in the research area are constructed;the sedimentary facies and development models of reservoirs are suggested in this paper.Research shows that the main reservoir rocks in the study area are limestone and a small amount of dolomite.By analyzing the sedimentary facies of the core,3 sedimentary facies,4 sedimentary subfacies and 6 sedimentary microfacies are identified in the research area.Under the theoretical guidance of Vail sequence stratigraphic pattern,3,4 and 1 three-level sequences in the Penglaiba Fm,Yingshan Fm and Yijianfang Fm are clsssfyed,respectively.Based on the comprehensive analysis of cores observation and thin section microscopic identification,8 kinds of carbonate diagenesis are identified in the studied area,one of them such as fracturing,dissolution and dolomitization belong to the constructive diagenesis,another such as recrystallization,cementation,siliconization and compaction belong to the destructive diagenesisThe main reservoir space of carbonate in the Shunbei area are pores,caves and fractures;according to the combination type of reservoir space,three kinds of reservoirs such as limestone cave-fractured reservoir,dolomite porous reservoir and fractured reservoir and their development models are suggested.The key controlling factors of reservoir development in the Shunbei Area may be ascribed to strike-slip fault system of multi-stage activities,different types karstification at different period.