Numerical Modeling of Spontaneous Imbibition and Investigating the Impact of Boundary Conditions on the Oil Recovery

In this work, a reliable mathematical model for numerical modeling of co-current and counter-current spontaneous imbibition in 1D and 2D modes is presented using MATLAB software and validated. Then, several studies are conducted on the effect of boundary conditions on the imbibition process. Results show that the oil recovery in co-current imbibition was 1.5 times greater than counter-current imbibition after 20 days. The results also show that in blocks with different heights, oil recovery is different. Investigation of the counter-current spontaneous imbibition in 2D mode in a large matrix block fully immersed in water indicated the effect of the gravity force in doubling the oil recovery after 120 days. Moreover, reducing the matrix block-water contact results in a decrease in the performance of imbibition process in the oil production so that the amount of the counter-current imbibition oil recovery decreased from 49% (four faces in contact with water) to 30% (one face in contact with water) after 10 days. The results show the increase of the water-contacted boundaries improves the spontaneous imbibition process efficiency.