Experimental and numerical study of vapor extraction process (VAPEX) in heavy oil fractured reservoir

Heavy oil occurring in carbonate reservoir, mostly fractured, is an important resource which accounts for one-third of the total heavy oil world-wide. However production from such reservoir is challenging, due to very high oil viscosity. The Vapor Extraction (Vapex) process, a newly developed Enhanced Oil Recovery technique, has been studied theoretically and experimentally for conventional heavy oil reservoirs. While applicability of this process in naturally fractured reservoir has not been addressed yet. In this work, vapor extraction process was studied by using a laboratory cell which consists of a matrix block surrounded by horizontal and vertical fractures. Scaling analysis was used to scale up the Vapex process in fractured reservoirs and compare the involved forces in both experimental model and real reservoir. Moreover, for extrapolating the laboratory results to reservoir condition, a numerical model has been developed by CMG simulation software and was validated with experimental data. Experimental results indicate significant difference in the pattern of solvent flow in fractured model compared with the conventional model and also presence of fracture network can compensate the low permeability of matrix block and enhance the whole process.