A Method for Characterization of Flow Units Between Injection-Production Wells Using Performance Data

This paper presents a novel data mining method to characterize the flow units between injection and production wells in a waterflood, using carefully implemented variations in injection rates. The method allows the computation of weight factors representing th e influence of any of the injectors surrounding a given producer. The weight factors are used to characterize the effective contribution of injection wells to the total gross production in surrounding production wells. A wavelet approach is used to design the perturbation in the injection rates and to analyze the observed variation s in the gross production rates. Tracking the contribution of injectors to various producers can help in balancing voidage-replacement in waterflood optimization. A second application is reservoi r characterization, where information provided by the proposed procedure can help in mapping high permeability flow units such as channels and fractures as well as flow barriers between wells. The method was successfully calibrated and tested for simulated line drive and five spot patterns with various assumed flow units and flow heterogeneity conditions. The paper also includes a case study for a tight formation waterflood where the weight factors are intended to delineate the pattern of natural fractures causing preferential flows.