Reservoir characteristics and classification evaluation of diamictites in Es3L of A Oilfield
Due to an unclear understanding of the characteristics of different types of diamictite reservoirs in the Lower Submember of the 3rd Member of the Econe Shahejie Formation(Es3L)in A Oilfield,the characteristics of diamictite reservoirs were comprehensively studied with data from drilling,logging,laboratory and production of development wells in the study area,and the productivity evaluation index of development wells was introduced to classify and evaluate the reservoirs.The results showed that:1)The delta sedimentary system and the shore-shallow lake mixed beach-bar sedimentary system are developed in Es3L in the study area.2)The types of reservoir rocks are mainly calcareous sandstone,dolomitic sandstone,sandy limestone,and sandy dolomite.3)Most reservoir spaces are intergranular pores,dissolution pores and fractures are developed,the average porosity of the reservoir is 25.4％,and the average permeability is 55.1 mD.4)The productivity evaluation index of diamictite reservoirs weighted by three logging parameters of permeability,resistivity and carbonate content has a good correlation with the initial productivity of development wells.The initial productivity of a single well is greater than 110 m3/d when the productivity evaluation index is greater than 20.The initial productivity of a single well ranges from 40 to 70 m3/d when the productivity evaluation index is between 6 and 20.The initial productivity of a single well is less than 20 m3/d when the productivity evaluation index is less than 6.5)The reservoir can be divided into three categories:type Ⅰreservoirs with medium-high porosity and medium-high permeability are mainly distributed in the mixed dolomitic area of mixed beach-bar facies;type Ⅱ reservoirs with medium porosity and medium-low permeability are mainly distributed in the mixed dolomitic area of mixed beach-bar facies;type Ⅲ reservoirs with medium-low porosity and low permeability reservoirs are mainly distributed in the mixed argillaceous area of mixed beach-bar facies.
万方数据
维普
