Simulation studies on the application of horizontal wells in different types of heavy oil reservoirs

The horizontal well technology in combination with steam injection is being widely used for the development of heavy oil reservoirs. The recovery processes with horizontal wells mainly include steam stimulation, steam drive, and Steam-Assisted Gravity Drainage (SAGD). The feasibility study on thermal recovery with horizontal wells for different types of heavy oil reservoirs using numerical simulator is presented. It is shown that a different recovery process should be adopted in terms of the reservoir characteristics. Reservoir thickness and oil viscosity are the key parameters affecting the performance of thermal recovery with horizontal wells. For super-heavy oil reservoirs with oil viscosity less than 100,000 mPa-s and formation thickness greater than 5 meters, steam stimulation and steam flooding processes with horizontal wells can obtain good recovery performance. But for the extra-heavy oil reservoirs with oil viscosity greater than 100,000 mPa-s, the SAGD process must be adopted. However, for a successful SAGD project, the formation thickness must be greater than 20 meters due to drilling problem and gravity effect.