Reservoir Characteristics And Controlled Factors Analysis Of Feixianguan Formation In Yangjiaping-Zhengba South Area, Northeastern Sichuan

The exploration of the oolitic shoal reservoir in the Feixianguan Formation of Triassic in the northeastern Sichuan Basin has great exploration potential.However,there are fewer well locations in the study area,reservoir characteristics,reservoir control factors.The distribution law does not have a clear understanding,become the difficulty of restricting exploration.In this paper,the oolitic shoal reservoirs in the Feixianguan Formation of the Lower Triassic in Yangjiaping-Zhengba-southern area of northeastern Sichuan are studied,and the characteristics of reservoirs and developmental control factors are studied.Based on the theories of oil and gas geology,sedimentary geology,reservoir geology and geochemistry and geochemistry,the petrological characteristics of the study area are summarized on the basis of core.The lithologic assemblage,the corresponding characteristics of logging and the paleontological characteristics are the main basis,and the boundary of the strata is defined,and the inner part of Feixianguan Formation is divided into five cycles.The study area was established as an isolated carbonate platform deposition system,and the study area was divided into platform margin subfacies and open platform(intraday)subfacies.Based on the physical data of the core,combined with the actual production effect and the previous research results,it is considered that the reservoir lithology is dissolved oolitic dolomite,residual oolitic dolomite and bright oolitic dolomite.The types of porosities are mainly intergranular pores,intergranular pores,dolomite intergranular pores,intergranular dissolution and gypsum tuberculosis.Physical properties of the overall belongs to the special low hole,low permeability.The reservoir development in the study area is mainly controlled by sedimentation and diagenesis.Sedimentation controls the distribution of reservoirs and the final distribution of reservoirs.The edge of the platform edge of the platform and the development of the open platform of the beach for the study area of the advantages of sedimentary facies.Diagenesis is the key to the formation of reservoirs.The diagenesis of the study area is divided into constructive diagenesis and destructive diagenesis according to the influence of reservoirs.Compaction,pressure dissolution and cementation are destructive diagenesis.Dissolution and dolomitization are constructive diagenesis.According to the petrological characteristics,there are two periods of dissolution in the study area,ie,the dissolution of the same period and the dissolution effect during the burial period.According to petrological characteristics and geochemical characteristics,it is considered that the dolomite model in the study area is divided into three categories:near-surface dolomite model,buried dolomite model and tectonic hydrothermal dolomitization model.The reservoirs in the study area are classified into three types:?,? and ?.The reservoirs in the study area are dominated by class ? and ? reservoirs.In the vertical direction,the reservoirs are distributed in the ?,? and ? cycles of Feixianguan Formation.The reservoirs in the margin are mainly developed in the ? cycle,and the reservoirs in the open platform are mainly developed in the ? cycle.On the plane,the cycle I reservoir is mainly distributed in Yangjiaping,Huangjinchang,Dongsheng,Wulong,Tieshanpo West,Huanglong field,Luojiazhai,Gunziping,and Jinzhuoping in the open platform.Cyclops ?reservoirs are mainly distributed in the Huangjinchang,Qili North,Gunziping,Yangjiaping,Luojiazhai area,was "L"-like.The cyclic ? reservoir is mainly distributed in the area of Zhengba South and Huanglong field.