Numerical evaluation of a combined chemical enhanced oil recovery process with polymer and nanoparticles based on experimental observations

Abstract

Polymer flooding is the most widely implemented chemical enhanced oil recovery (CEOR) process. However, polymer degradation, caused by chemical, thermal, and mechanical stresses, is still the most notable limitation on the implementation of the technology at the field scale. Recent studies have shown that the addition of nanoparticles in a traditional polymer flooding can improve operating conditions and hydrocarbon production. Thus, a comprehensive numerical simulation study is presented to model the performance of the co-injection of polymers with nanoparticles in oil reservoirs. An articulated process was followed to take into account most of the physical and chemical mechanisms of the technique. Initially, a conceptual model was developed by identifying relevant mass transport and surface mechanisms, and their dynamics. The following phases are accounted in the model: oleic, volatile, and aqueous. Then, local mass balance equations were written for the following components: oil, gas, water, solid nanoparticles and polymers. An extended black-oil model for the hydrocarbon and aqueous phases was used. Constitutive equations were specified for polymer adsorption, rheology, degradation, and nanoparticles retention and remobilization, as well. The numerical strategy was described for numerically solving the Jacobian matrix. The model was subsequently validated in two steps: initially, the simulation results of a polymer flooding are compared to the ones obtained using a commercial software. Then, the nanoparticles transport and retention on the solid matrix was validated with experimental core-flooding tests reported in specialized literature. A set of numerical experiments of the co-injection of polymer-nanoparticles were done, showing that the synergy between both chemical species allowed to retain the viscoelastic network, which considerably improves operational and production parameters. This investigation provides a powerful tool for Oil & Gas industry and can be used to design novel CEOR deployment strategies in sandstone reservoirs.