Characterization of Pore Structure and Two-Phase Seepage Pattern in Sandstone Conglomerate Based on CT Scanning

Abstract

Oil and gas occurrence characteristics and seepage characteristics of tight reservoirs are the key to production. CT technology can monitor displacement and advance seepage front in time In this chapter, NMR experiments of spontaneous imbibition and CT monitoring experiments of differential pressure displacement are carried out for dense conglomerate to clarify the law of two-phase seepage. The results show that in spontaneous imbibition, the fluid circulation in the pore of tight glutenite is high, and there is no micro-fracture The pore volume of clay minerals with high content increases when exposed to water, which improves the imbibition recovery ratio However, the highly heterogeneous gravel distribution increases the complexity of seepage path and thus enhances the imbibition recovery ratio. The strong heterogeneity of sandy conglomerate leads to the formation of preponderant passages in seepage In the early stage of displacement, the water flooding effect is poor and a large amount of water accumulates With the increase of displacement time, there is no obvious change in oil saturation at both ends of the middle part of a large number of water rock samples The oil saturation is lower at both ends and higher in the middle.