Scaled physical model studies of the steam drive process. Second annual report, September 1978-September 1979

A scaled physical model was operated to simulate steam drive operations in five-spot patterns with reservoir and operational parameters similar to those encountered in California reservoirs. The goal of this study was to elucidate the role of two important controllable parameters, viz., steam injection rate and steam quality and to explore the role of two important factors, oil viscosity and reservoir permeability on the performance of the steam drive. In addition, the influence of bottom water and a basal permeable layer were investigated. The experiments demonstrated that there is an optimum injection rate; that in the vicinity of this optimum an increased quantity results in improved oil steam ratios; that the viscosity of the oil at steam temperature, raised to a fractional power, 0.5, appears to correlate with oil production; that permeabilities in the darcy range have little effect on performance, but an increasing one with low viscosity oil, and that bottom water, which facilitates injection, results in toorer early performance but one which eventually rivals the oil/steam ratio of a uniform reservoir at a somewhat higher recovery of original oil in place. It has been concluded that the major value of the physical model is in describing the role of the reservoir and operational parameters of a class of steam drive operations rather than providing an exact prediction of a given operation.The problem of supplying the latter lies in the virtually impossible-to-define distribution of oil, gas and water in the reservoir on initiating the steam drive. Two years of this project have now been completed. During the forthcoming final phase of the program, effort will be devoted to studying the relative effects of solvent and gas addition to the steam, of diurnal injection, and of (horizontal) well placement.