Improved Polymer-Flood Management Using Streamlines

Abstract

Summary Recently, modern streamline (SL) simulation has been extended to polymer flooding. In this work, we extend the applicability of SL simulation further for efficient management of polymer-injection projects. We first present our method and then demonstrate the applicability of our approach using a Romanian field as an example. Owing to the price of polymers, an optimized injection strategy is crucial to minimize costs, maximize sweep, and thereby ensure profitability of a polymer flood. The biggest advantage of SL simulation in comparison to traditional finite-difference (FD) modeling is that polymer floods can be optimized on an individual-well-pattern basis. By being able to plot cumulative oil produced as a function of polymer injected for an individual well pattern, underperforming patterns—injectors and associated offset producers—can be indentified easily and rates, concentration, and slug size can be modified to improve the local efficiency of the flood. In this paper, we introduced a new metric—the polymer-injection efficiency as a function of time for each pattern—and we show how it is central to containing costs while improving oil recovery. We demonstrate our management method on a Romanian oil field that has been operating since 1961 with 21 injectors and 136 producers. We show that the utility factor (UF) (mass of polymers injected per volume of incremental oil produced) can be reduced while sustaining oil recovery. We conclude with a discussion on SL simulation as an enabling technology for reservoir-management decisions for polymer floods.