TABLE OF CONTENTS Most reservoir engineering calculations involve the use of the material balance equation(MBE). Some of the most useful applications of the MBE require the concurrent use of fluid flow equations, e.g., Darcy s equation. Combining the two concepts would enable the engineer to predict the reservoir future production performance as a function of time. Without the fluid flow concepts, the MBE simply provides performance as a function of the average reservoir pressure. Prediction of the reservoir future performance is ordinarily performed in the following three phases:
Phase 1: The first phase involves the use of the MBE in a predictive mode to estimate cumulative hydrocarbon production and fractional oil recovery as a function of declining reservoir pressure and increasing gas oil ratio (GOR). These results are incomplete, however, because they give no indication of the time that it will take to recover oil at any depletion stage. In addition, this stage of calculations is performed without considering:
the actual number of wells;
the location of wells;
the production rate of individual wells;
the time required to deplete the reservoir.
Phase 2: To determine recovery profile as a function of time, it is necessary to generate individual well performance profile with declining reservoir pressure. This phase documents different techniques that are designed to model the production performance of vertical and horizontal wells.
Phase 3: The third stage of prediction is the time production phase. In these calculations, the reservoir and well performance data is correlated with time. It is necessary...
