A comprehensive, three-dimensional, numerical model study was conducted to optimize steamflood performance of dipping, heavy-oil reservoirs. Results show that a reduction in steam (heat) injection rate after steam breakthrough is much superior to the constant rate injection. A linear rate reduction is preferred, when rate reduction is initiated at steam breakthrough. However, if the rate reduction is started after the entire project area is covered with steam (which is the case for several existing projects), an exponential rate reduction is preferable.
A line drive configuration with rows of injectors and producers along the direction of the dip and injectors located near the downdip edge of the patten is preferred. This configuration better utilizes gravity override and drainage and recovers significant additional oil over conventional pattern drives, especially for higher viscosity oils. For confined systems, single-pattern results agree well with multi-pattern (up to six patterns in the direction of dip).