Coupling Nanoparticles with Waterflooding to Increase Water Sweep Efficiency for High Fines-Containing Reservoir - Lab and Reservoir Simulation Results

Waterflooding is an established conventional method to improve oil recovery. When water flows into pores in a rock formation occupied by hydrocarbons, clays and other formation fines are released and flow with the injection water. Left unaddressed, the released formation particles can accumulate and plug the pore throats in the flow channels, which cause higher water injection pressure, lower water sweep-efficiency and lower oil recovery. Chemical additives in the injection water to stabilize formation clays and fine particles during waterflooding operations are partially helpful. Several major operators established a goal for 70% oil recovery, motivating the research of higher performing waterflooding formulations. As the nanoparticle-loaded water drives hydrocarbons toward the producers, the nanoparticles fixate formation fines at their sources in the water flow channels, resulting in fewer fines accumulating at the near-wellbore region of the producers (causing less choking to the production of hydrocarbons) and resulting in water-sweep-efficiency increases. This paper presents the results with and without using nanoparticles in simulated waterfloodings. In addition to cleaner water effluent, lower pressure drop occurs across the porous media containing nanoparticles under the same flow rate of 5%KCl and the same porous media compositions of sand and simulated formation fines. Full reservoir simulation details the benefits of coupling the nanoparticles and waterflooding in high fines-containing reservoirs with various reservoir properties. This paper presents the use of select nanoparticles in waterflooding to significantly improve oil recovery in reservoirs susceptible to formation fines migration. The research shows the unique ability of select nanoparticles in stabilizing formation clays and fines in waterflooding operations. The lab results demonstrate a much higher performance of the new nanoparticle-blended waterflooding than the currently used technology of stabilizers for formation clays and fine particles. Lab tests, even visually, show a clear improvement of the water-effluent quality (less fines) when the nanoparticle-blended waterflooding is pushed through the lab-constructed permeable media. The simulation resulted in 37% more production than regular waterflooding in a higher permeability reservoir case and 95% greater production in a lower permeability reservoir scenario. The paper includes the scientific principle behind the nanoparticle functioning, detailed lab results and the reservoir simulations.