Simulation Investigation of Spontaneous Water Imbibition in a Matrix-Fracture System

Spontaneous imbibition plays an important role in the oil recovery from the fractured reservoirs. The principle driving mechanisms behind this process are capillary and buoyancy (gravity) forces which counteract the resistance. However, over time, these driving mechanisms decline, resulting in the lower production velocity from the matrix block. There are numerous studies done on the experimental and numerical investigation of spontaneous imbibition in the matrix-fracture systems. Nevertheless, the numbers of the simulation analysis over this subject are not quite considerable. This study mainly concentrates on the simulation of the co-current spontaneous imbibition in the single matrix block, which is fully immersed in the water. The selected simulator is COMSOL Multiphysics. To validate the results, a program is run in the MATLAB based on the related correlations in this domain. Regarding the capillary mechanism as the main problem for the success of validation and scrutinizing its effect, the MATLAB results support the COMSOL analyses in a reasonable way.

Keywords:

Spontaneous imbibition , Capillary pressure , Buoyancy pressure , Fractured reservoirs , Matrix-fracture systems.