Enhanced Oil Recovery in Fractured Carbonate Reservoirs

A collaboration between 3 University research groups in France, UK and Norway and 3 oil companies will try to improve oil recovery in fractured carbonate reservoirs by establishing a better understanding of the dominant in-situ oil recovery mechanisms dur ing stimulated production; including waterfloods and gas injection, emphasizing the effects from wettability. An EOR-strategy for gas- and waterfloods in carbonates is to induce wettability alteration to create wetting phase bridging, thus a goal will be to determine the amounts of additional 1)viscous waterflood oil recovery by establishing water continuity over fractures or 2)improved gas sweep by establishing oil continuity across fractures. Using complimentary in-situ imaging (UoB and ConocoPhillips); NTI in large scale fractured blocks of carbonate rock, with emphasis on oil wet conditions, and using MRI with high spatial resolutions of fluid flow and saturation development inside fractures in stacked core plug experiments it will be determined how t he fracture network impacts the oil recovery mechanisms. History matching of the experiments by numerical simulations will compare not only fluid production, but also the local in-situ fluid advancement. The project will develop improved predictive numeri cal tools by focusing on the understanding of the pore-scale displacement processes using pore network models (Imperial College) and develop averaged transport properties for use in field-scale simulation of fractured reservoirs. The project will expand t he understanding of wetting phase bridging to 3-phase flow by conducting 3-phase experiments at LEPT-ENSAM, Bordeaux. Project deliverables are detailed description and determination of oil recovery locally around fractures, impact from fractures at variou s wettabilities, experimental and numerical determination and prediction of mechanistic fluid flow behaviour across fractures and suggested strategies for increased oil recovery in fractured carbonate reservoirs.