This paper addresses a study of gas-oil gravity drainage in fractured carbonate rock subjected to equilibrium gas injection in low interfacial tension. The purpose of the four experiments described in the paper was to investigate gas injection in fractured carbonate reservoirs, focusing on gravity drainage using equilibrium gas followed by re-pressurization . Gas injection experiments were performed on 20 cm long and low permeable outcrop chalk core surrounded with a fracture established with a novel experimental set-up in reservoir conditions. The core was saturated with binary mixture live oil consisting of C1 and C7 of a known composition, while the fracture was filled with sealing material to obtain a homogeneous saturation.After core initialization, the sealing material was removed by increasing the temperature to higher than its melting point. Gas was then injected into the fracture. Gravity drainage experiments were performed in low interfacial tension (< 0.5 mN/m) where the IFT between the phases were measured experimentally. Pressure and temperature were selected to give proper IFT. Experiments were performed at different pressures and reversibility of the effect of the interfacial tension was checked by re- pressurization process. The oil recovered from the bottom side of the block was measured versus time.
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