Reservoir characteristics and main controlling factors of Fu 3 member of Qintong west slope

Thin layer sand of delta front was developed in Fu 3 member of Qintong west slope and the reservoir space was mainly composed of intergranular pores and secondary inter-crystalline micropores, and dissolution pores were developed locally. The cementation is mainly of clay mineral cementation, and the comprehensive reservoir evaluation is medium and low porosity, low and ultra-low permeability and fine throat reservoir. The types of sedimentary microfacies and diagenesis are the controlling factors of reservoir physical properties.The reservoir physical properties are better in the area of micro-facies development of underwater distributary channel, and worse in the area of distal bar development. Compaction and cementation are destructive to the reservoir, while the dissolution is conducive to the improvement of reservoir physical properties. The reservoirs in the Fu 3 member of Qintong west slope can be divided into Ⅰ , Ⅱ and Ⅲ categories.