A Novel Method for Mapping Fractures and High Permeability Channels in Waterfloods Using Injection and Production Rates

Abstract

AbstractThis paper extends the work reported in SPE114222 for managing waterfloods using estimation of flow characteristics from only injection and production rates. The method first estimates the finite impulse response (FIR) curve corresponding to the fluid-flow between all injector-producer pairs. This FIR curve is analogous to the pressure curves obtained from pulse testing. Reservoir parameters, such as connectivity between wells, can be estimated from this curve, which can also be used to characterize variations of relative flow as a function of storage capacity (F-C plots), thus making it possible to quantify the heterogeneity of flow paths between wells.Our proposed method is capable of identifying the flow channel relationships between all injector-producer well pairs. This helps in reservoir characterization, where information provided by the proposed procedure can describe the characteristics of flow-path between injector-producer pairs. It can also help in waterflood optimization by tracking sweep efficiency and balancing voidage-replacement. The method has been successfully tested and calibrated for simulated line drive patterns with various fracture geometry conditions. It successfully quantifies the interwell connectivity and the heterogeneous properties in the numerical simulations.Our procedure has several advantages over pulse testing and tracer tests. In comparison to pulse testing, pressure data is not required and the only data needed are injection/production rates, which are often routinely available with high temporal resolution for many reservoirs. The quality of measured production rates affects the estimated properties. Because the proposed procedure can be routinely performed and implemented, the proposed procedure leads to a dynamic approach for reservoir and fluid flow mapping, where the results can be refined over time. Additionally, our procedure could also be used for better designs of pulse or tracer tests. Finally, once the flow channels are mapped, one can balance the flood and make diagnostic predictions about future response under any given injector scenarios.