Understanding Foamy Oil Mechanisms for Heavy Oil Reservoirs During Primary Production

A set of experiments in porous media was performed to determine oil recovery factor during natural depletion for a heavy oil reservoir. Results on {open_quotes}critical or mobile{close_quotes} gas saturation, produced fluid characterization, residual oil saturation, production profile and effective viscosity versus pressure are presented. In order to characterize the ability of the heavy oil to trap the released gas, conventional and non conventional PVT tests were carried out. By comparing the experimental results during differential liberation tests, a gas trapping factor for the oil was obtained. It accounts for the amount of solution gas that has been thermodynamically released but does not form instantaneously a free gas cap. The so called pseudo-bubble pressure was obtained. In this work the hypothesis involved in the {open_quotes}Low Viscosity Model{close_quotes} was also tested.