Multi-Criteria Analysis and Optimization of Waterflood Systems in Brownfields

Abstract

This paper describes a methodology for waterflooding pattern optimization based on multi-criteria analysis of the interaction between producers and injectors. This method takes advantage on the use of streamlines which are generated from the post-processing of finite difference simulation results to define the flow paths between injectors and producers and characterize flow allocation between interacting wells. This information is then combined with well production/injection data (oil / water rates, pressures etc.) to calculate parameters like compensation ratio and injection efficiency for each well. Having all this information, a set of cross-plots is used to rank the producers and injectors by their sweep / drainage efficiency. The results of such analysis allows the planning of workovers, optimization and allocation of the volumes of injected water and ultimately enables a comparative assessment of the efficiency of each individual workover event in terms of incremental oil production, water-cut reduction and decrease in non-effective water injection. One of the advantages of this method is the use of already available results from finite difference simulation. This fact dramatically increases the time available for the waterflood optimization process and significantly widen the range of scenarios where streamlines technologies can be applied. Moreover, this approach does not require significant or time-consuming computational efforts, which make it a very convenient decision-making tool for field operations planning.