Document Type : Review paper


Department of Petroleum Engineering, Ahwaz Faculty of Petroleum Engineering, Petroleum University of Technology (PUT), Ahwaz, Iran



Spontaneous imbibition of aquifer brine is one of the main mechanisms of hydrocarbon recovery in the water-invaded zone of fractured reservoirs. Most of the fractured reservoir rocks are oil-wet carbonate. Simulation of spontaneous imbibition becomes more important when an enhanced oil recovery (EOR) method such as modified salinity injection is applied for wettability alteration towards a more water-wet state. Since 1962, many scaling equations have been proposed to develop transfer functions and improve the simulation of spontaneous imbibition. Unfortunately, most of those proposed scaling equations are developed based on ideal conditions in the laboratory and, hence, have not considered the real conditions of a fractured reservoir. High temperature, rock oil-wettability, live oil properties, wettability alteration, lithology specification and gravity force are among important factors that are ignored in most of the developed scaling equations in the literature. These effective but neglected elements can cause over-/under-estimation of hydrocarbon recovery by spontaneous imbibition. In this review, literature scaling equations advantages and limitations (with a critical point of view) are discussed and many research topics are recommended for researchers interested in experimental works or data analysis in the spontaneous imbibition research area. The ideal goal of decades of research in this area is to reach a general scaling equation with a special term for each specific lithology and EOR strategy.


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