Spontaneous Imbibition in Niger Delta Cores

Abstract

Abstract Spontaneous imbibition is a process where the non-wetting fluid is displaced by the wetting fluid in a porous medium by means of capillary forces. Spontaneous imbibition plays a key role in oil recovery. This paper presents experimental data for countercurrent spontaneous imbibition into cores with different porosity and permeability. Experiments were performed using Niger Delta sandstone core samples. Core samples were initially saturated with brine. Crude oil samples of different viscosities were then injected into the core samples. Synthetic reservoir brine was used as the wetting phase. Scaling the experimental data of spontaneous imbibition with different injection fluids is crucial to properly design improved recovery methods and to predict their performances. In this work an analytical solution of a model describing counter-current imbibition was derived. Recovery curves were used for scaling the data in different cores and at different interfacial tensions. The scaling approach developed by Li and Horne yielded satisfactory correlation for all the cases. The results obtained were compared with the model we developed which also correlated satisfactorily. We also used the solutions of the model we developed to gain insight into the parameters that control oil recovery by spontaneous imbibition.