Reservoir characteristics of lower sub-member 4 of Shahejie Formation in Luojia area,Bonan Sag
The lower forth member of Shahejie Formation in Luojia area of Bonan Sag has a good exploration prospect,with several wells of high industrial oil flow.However,the current study on its reservoir character-istics is weak,which restricts the exploration and development.To define the reservoir characteristics,the reservoir petrology,physical properties and pore texture characteristics were studied by combining the data of core,cast thin section,physical properties and high pressure mercury injection.The results show that:the reservoir lithology is composed of fine-medium lithic arkose and fine-medium arkosic arenite.The reservoir spaces are mainly intergranular pores,and a small number of intragranular pores are developed.Physical properties vary greatly,it developed medium-high porosity with medium-high permeability,and the pore structure is generally good.According to physical property data,pore type,curve shape of high-pressure mercury injection and various parameters,the pore structure can be divided into three types from good to poor:Ⅰ,Ⅱ and Ⅲ,with Ⅱ as the main type and Ⅰ as the second.
Bonan SagLuojia areathe lower member 4 of the Shahejie Formationreservoir characteris-ticspore structure