A review of the phenomenon of counter-current spontaneous imbibition: Analysis and data interpretation

Spontaneous imbibition is an area of significant interest to the petroleum industry due to its large contribution to oil production in mature and fractured fields. This work discusses the physics behind the phenomenon of counter-current spontaneous imbibition: the key studies and experiments are reviewed along with how these projects influenced the understanding of the process. The work also simplifies the derivation of the semi-analytical solution of counter-current spontaneous imbibition (Schmid et al. 2011, 2016) and the equation by Schmid et al. (2012) to upscale the rate of spontaneous imbibition from the core to the field scales. Numerical applications of the solution for counter-current spontaneous imbibition, such as determination of relative permeability and capillary pressure, and oil recovery calculations are also discussed. The purpose of this work is to provide a clear and presentative overview of the main mathematical and theoretical concepts and their applications. The work compiles previous significant contributions to the topic and addresses development and applications of the semi-analytical solution, counter-current SI upscaling schemes, imbibition mechanisms and role of capillary backpressure.