Reservoir Characteristics Of Feixianguan Formation Gas Reservoirs In Shuangjiaba Area And Optimization Of Favorable Areas

This paper takes Shuangjiaba Feixianguan Formation's oolitic reservoir for the study.This paper consists of sedimentology,reservoir geology,developmentgeology,oil-gas geology and structural geology as a theoretical guide.On the basis of previous studies,this paper makes full use of study area's drilling,logging and logging data.Then it conducts studies about the sequence stratigraphic division and comparison,sedimentary facies analysis,oolitic-bank distribution characteristics,reservoir characteristics,reservoir control factors,favorable area optimization in Shuangjiaba Feixianguan formation.Based on the upward shallowing cycle feature in study region,Feixianguan is divided into 5 sedimentary cycles.At the same time the characteristics of each cycle get analyzed.This study has set corresponding sedimentary phases and has divided the study area into everal subfacies:restricted and evaporate platform,open platform,edge platform,trough-slope facies and some micro facies,of which platform-margin facies as favourable oolitic reservoir's zone.For the open platform,the first to the third cycles are oolitic-bank growth stages.For the edge platform,the second and the third cycles are oolitic-bank growth stages.And in the rough-slope facies,the oolitic-bank growth is between the third and the fourth cycles.Within the study region,pore oolitic-bank reservoir is mainly developed.The oolitic dolomite reservoir properties are the best in the reservoir rock.From the study,the third class reservoir is the main reservoir,and the first and the second class reservoir barely exist in the study area.The reservoir's development is limited by three main factors:sedimentary facies,structural fracture and diagenesis.Prospecting oolitic-bank reservoir is mainly affected by the mixed water dolomization and burial dolomitization geological influence factors.Study suggests that the edge platform belt is better accumulation area for oil and gas.Oolitic gas reservoir is analyzed in the researched region,and the origin types of gas reservoir are further confirmed.The promising exploration belts are pointed out which are classified into class I and class II favorable areas.