A Simple Analytical Model for Simulating Heavy Oil Recovery by Cyclic Steam in Pressure-Depleted Reservoirs

The cyclic injection of steam to stimulate or produce wells in heavy oil reservoirs is extensively employed by the oil industry. The performance of such wells may be predicted from empirical correlations, simple analytical models or thermal reservoir simulators. Empirical correlations can be extremely useful for correlating data within a field and for predicting performance of new wells in that and similar fields. However, use of such correlations for situations much different from the ones that led to their development can be subject to large errors. On the other hand one can use a compositional thermal model to predict the performance of cyclic steam operations. While thermal models are based on the fundamental laws of conservations, the fluid flow is related to pressure gradient through the empirical concept of relative permeability. In addition, the inherent sophistication of a thermal model makes it sensitive to rock properties, fluid properties and geological features. Much of this information is often unknown and must be estimated from limited data and experience in similar situations.