Carboxymethyl cellulose-based preformed particle gels for water management in oil and gas reservoirs

Abstract

Carboxymethyl cellulose (CMC) based materials have been proposed as preformed particle gels (PPGs) for reducing excessive water production in oil and gas reservoirs. Multi-sized dry particles ranging between 100 and 1180 μm have been synthesized using microwave-assisted grafting copolymerization of CMC and acrylamide (AM)/n,n''-methylene-bisacrylamide (MBA). FTIR and SEM confirmed CMC crosslinked polyacrylamide's chemical structure and morphology (CMC/CPAM). Thermo-gravimetric analysis has demonstrated the thermal stability of dry PPGs up to 309 °C. CMC/CPAM showed slightly high absorbency in brine 2 (TDS = 67.3 g/L) compared to brine 1 (TDS = 33.65 g/L), 1% NaCl, and deionized water, with swelling ratios (SR) between 7.1 and 12.9 g/g at room temperature regulated by MBA weight ratio. The effect of particle size, pH, temperature, and aging on SR and mechanical strength was investigated and discussed based on the CMC/CPAM structures. The swollen PPGs showed excellent resistance to temperatures up to 100 °C with a storage modulus of 9 kPa. The particle size was estimated based on salinity, pH, and temperature and controlled between 118 μm and 3 mm at high temperature (100 °C) and high salinity (TDS = 67.3 g/L) conditions to match the need for carbonate reservoirs. Core flooding experiments demonstrated the effective plugging efficiency of the PPG in open fracture models.