A common problem during the lifetime of oil and gas producing wells is the surge of the water-cut. High water-cut leads to poor economics due to oil productivity losse and increased water handling and operational cost. A widely used chemical water shut-off method relies on gelling systems consisting of a water soluble polymer and a crosslinking agent. This paper reports an experimental study of the shut-off water flow in fractured carbonate system using a polymer gel consisting of a copolymer of acrylamide-sodium acrylate crosslinked with chromium acetate. The experimental study consists of two parts: (a) the rheological characterization of the gel in presence of high salinity formation water (total dissolved solid of 172,000 ppm) and (b) core flood experiments using a length-wise artificially fractured limestone core (fracture width of 1 mm). From the rheological experiments, it was found that the gel system made with high saline formation water is stable at high temperatures (at 85 °C) for 4 days. More crssolinking of polymer chains occurred in presence of formation water. The core flow experiments revealed that gel is strongly blocking agent reducing the fracture conductivity by four orders of magnitude.

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