A Mathematical Model of Reservoir Response During the Cyclic Injection of Steam

A mathematical model of reservoir behavior during one cycle of the intermittent steam injection process is presented. A cycle of the process is considered to be made up of 3 stages: injection, condensation, and production. The model concentrates on behavior during the production stage. The influence of several parameters on production improvement is described, using the results obtained with a numerical equivalent of the model. The reservoir system parameters considered are thickness, reservoir thermal conductivity, oil viscosity, solution gas-oil ratio, and the change in oil effective permeability with temperature. Operating parameters investigated are heat injection rate, steam temperature, and cumulative injection time. The model appears to perform fairly well in matching the behavior observed during an actual test. This makes the model a useful means of selecting projects. The model may also be utilized to select an optimum set of operating conditions for a particular project. (18 refs.)