Preformed Particle Gel Strengthened with the Reinforcement of Nanomaterial for the Control of Unwanted Water Production in Brownfield Oil Reservoirs: Synthesis, Characterization, and Performance Evaluation.

Preformed particle gels (PPGs) have been introduced as an efficacious chemical technology to alleviate or reduce unwanted water production from heterogeneous mature oil fields. However, there are some limitations to the existing developed PPGs, such as mechanical robustness, temperature stability, and formation fluid resistance. To address these limitations, a nanomaterial-reinforced preformed particle gel was introduced. In this current research work, the authors have reported a new type of novel nanomaterial-reinforced PPG using the reinforcement of zinc oxide (ZnO) nanomaterial, methacrylic acid, N,N-dimethyl acrylamide as a monomer, and N,N-methylene bis acrylamide as a cross-linker. The newly developed reinforced PPG, termed RF-PPG, shows high mechanical strength and exceptional long-term thermal resistance, salinity tolerance, and pH resistance. The resulting PPG (RF-PPG) exhibited superior performance compared to conventional PPG (without nanomaterial), i.e., WRF-PPG. Preformed particle gel with reinforcement (RF-PPG) has shown the equilibrium swelling of 119 and 32 in distilled water and 30,000 ppm of NaCl brine solution, respectively. The elastic modulus of RF-PPG is up to 2100 Pa, which is significantly higher than the particle gel without reinforcement (WRF-PPG), i.e., 600 Pa. Moreover, the swelling characteristics of RF-PPG, in high salinity and pH, show less variation, although the swelling capacity of RF-PPG is less in different solvents as compared to WRF-PPG. The nanomaterial reinforcement significantly improved the long-term thermal resistance for more than 185 days in 30,000 ppm of NaCl brine solution at 100 °C and shows an increment in swelling at higher temperatures. Laboratory sandpack flooding study demonstrated that RF-PPG provides exceptional plugging capacity of more than 90% and residual resistance factor of 11.92 and 15.03 for high permeable sandpacks at 100 °C. Considering the unique characteristics of the engineered preformed particle gel, RF-PPG is ideally suited for water shutoff jobs in heterogeneous reservoirs.