Genetic Mechanism And Characteristics Of High Water Consumption Zones Of The Delta Front Mouth Bar Reservoir In No.8 Sand Group Of The Second Member Of Shahejie Formation In The South Of Tuo11 Area

Reservoir in No.8 sand group of the second member of Shahejie Formation in the south of Tuo11 area is a self-contained fault block reservoir under delta front sedimentary environment,with complex geological conditions.Since the reservoir was put into development in 1965,it has entered the late stage of ultra-high water cut,and high water consumption zones have been formed in some high permeability zones,showing the development status of high comprehensive water cut and low recovery rate.However,the unclear spatial distribution of high water consumption zones has affected the further potential tapping of remaining oil.In order to solve this problem,comprehensive use of core,logging,seismic and production dynamic data,guided by the development geological theories,and based on the establishment of fine stratigraphic framework in the study area,the reservoir architecture classification scheme 4,5 and 6 level architecture characteristics and distribution patterns of the No.8 sand group in the second member of Shahejie formation are defined.Starting from the difference in reservoir quality of different architecture units,the dominant architecture units for the development of high water consumption zones are summarized as bar 2,bar 1 and upside channel.The paper analyzes the genetic mechanism of high water consumption zones from two aspects of original geological factors and later development factors,and proposes that the types and characteristics of reservoir architecture play a major role in the development degree,location and geometric shape of high water consumption zones.At the same time,five reservoir parameters such as thickness,permeability,permeability ratio and permeability breakthrough coefficient,and three fluid parameters such as water saturation,pore sweep extent and water content are selected as characterization parameters of high water consumption zones,and identification standards of high water consumption zones are established.There are three types of high water consumption zones:developmental,potential and undeveloped.Combined with production dynamic data,the spatial distribution of high water consumption zones in the whole region is predicted,the distribution law of high water consumption zones is revealed,and the characteristics that the high water consumption zones are mostly vertical distributed in8₃sub layer and are mainly distributed in the dense well network areas in the north and the middle are pointed out.