Influence of different pore structure types on the occurrence features of movable fluid in Chang-10 reservoir in Wuqi–Ansai Oilfield

Abstract Chang-10 reservoir in Wuqi–Ansai oilfield of Ordos Basin is restricted by its strong microscopic heterogeneity, complicated pore structure and unclear oil–water movement rules. The technology nuclear magnetic resonance (NMR) an excellent method to quantitatively evaluate the fluid different types, experiments such as cast thin slices, scanning electron microscope (SEM) high-pressure mercury injection were also used analyze differences occurrence features types their influencing factors. experimental results show that sandstone Oilfield are mainly medium-fine arkose lithic arkose. intergranular pore, feldspar turbiditic zeolite cuttings pore. combination type pore-throat belongs mesopore–micropore microlarynx–microlarynx. By experiment analyzed characteristic capillary pressure curve, structures classified into Type I, II, III IV due movable features. obviously controlled pore-throat, orders control effect from weak saturation gradually becomes low when radius decreases.