Chemical EOR Strategy Optimization in the Presence of Economic and Technical Uncertainty

Field implementation of chemical EOR is subject to significant uncertainty economic and technical. This study presents a workflow and a method to produce optimal Chemical EOR policies considering uncertainty in heterogeneity, reservoir properties and economic costs. The study implements an approximate dynamic programming algorithm developed earlier known as the Least Squares Probabilistic Collocation method. In this study this algorithm is extended to incorporate uncertainty in reservoir heterogeneity. The technical uncertainties considered were the chemical flooding related properties. Reservoir permeability was also considered as a stochastic field and two methods were used to generate the stochastic realizations: two-point and multiple point statistical methods. The economic uncertainties considered were the oil price and chemical cost. Three reservoir models were used in implementing this method. Two-dimensional and a three dimensional reservoir model along with a synthetic fractured carbonate reservoir model that is analogous to Middle Eastern carbonate fields. The optimal policy was determined for the following control variables: chemical EOR process to be used and initiation time. Results show that it was possible to produce the optimal policies for chemical EOR implementation and that using the VoF concept supports the implementation of a dynamic strategy.