Study On Sedimentary Characteristics And Reservoir Control Factors Of The Middle Triassic Leikoupo Formation,Sichuan Basin

Sichuan Basin occupies an important position in China's petroleum-bearing basins.Among them,Marine carbonate formations are of particularly interest in oil and gas exploration in the Sichuan Basin.With the successive breakthrough of oil and gas exploration in the Leikoupo Formation,it has become a hot spot for oil and gas exploration.this paper is based on the investigation of the sedimentary background of the Leikoupo Formation in the Sichuan Basin,combined with the data of previous achievements and used drilling cores,well logs,field profiles,thin slices and other data to In-depth discussion the characteristics of sequence stratigraphic,sedimentary facies and storage.The Leikoupo Formation in the Sichuan Basin can be divided into two three-level sequences and both including high-level system domains and transgressive system domains;The sedimentary facies types of the Leikoupo Formation are dominated by evaporative platforms and limited platforms,and open platforms and platform marginal facies are developed in some areas;The dolomite reservoirs of the Leikoupo Formation have better physical properties than limestones,among which the microbial dolomite,granular dolomite,and powdered dolomite have good physical properties,which are the main reservoir rock.The reservoir of the Leikoupo Formation in the study area can be roughly divided into four categories:(1)the platform margin beach facies reservoirs are mainly developed in the third member of the Leikoupo Formation,distributed in the western marginal area of the Sichuan Basin;(2)the platform beach The facies reservoirs are developed in each interval of the Leikoupo Formation,mainly distributed in the western Sichuan Basin;(3)Microbial reefs Reservoirs are developed in the fourth member of the Leikoupo Formation,mainly distributed in the middle section of the western Sichuan Basin,and are distributed in a north-east and south-west.(4)Restricted tidal flat reservoirs are developed in each interval of the Leikoupo Formation,mainly distributed in Uplifted area in the central Sichuan Basin.Reservoir performance and distribution of the Leikoupo Formation are mainly affected by sedimentary facies and diagenesis.Sedimentary facies control reservoir lithology,and diagenesis affects the preservation of the original pores and the development of secondary pores.