Abstract
Application of non-Newtonian Power-law fluids (e.g. polymeric solutions) for production enhancement in petroleum reservoirs has increased over the last three decades. These fluids are often injected as viscous solutions to improve mobility ratio and enhance oil recovery during chemical flooding. As part of the flooding operation, surfactant (or micellar) solutions are first injected at the leading edge of the flood to reduce interfacial tension between water and oil. Subsequently, a slug of polymer solution is injected ahead of normal water to increase viscosity of the water, improve volumetric sweep efficiency and accelerate oil production. Analysis of pressure tests conducted pre and post injection, to evaluate mobility of these fluids, is more demanding than conventional techniques, which were developed strictly for Newtonian fluids. In naturally-fractured reservoirs, flow of non-Newtonian fluids is more complex due to fracture-matrix interaction which is usually resonated in the pressure footprints. Some models have been developed to aid interpretation of pressure tests, but boundary effects on down-hole measurements due to structural discontinuity and presence of an active aquifer, have not been thoroughly investigated.
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