Stability and flooding analysis of nanosilica/ NaCl /HPAM/SDS solution for enhanced heavy oil recovery

摘要

Oil and gas are main sources of energy globally. Limitations on these resources and the ability to explore and exploit them has led to the development of new technologies for enhanced oil recovery. The massive amounts of oil remain in reservoirs must be removed using common enhanced oil recovery methods and other complex methods. Nanotechnology can help solve many problems in the oil and gas industry. Nanoparticles can assist production of oil from reservoirs on the nanometer scale. Nanoparticles can increase oil recovery through polymer flooding, but there are few studies on polymer performance in the presence of nanoparticles and salt, especially HPAM. The current study investigated HPAM/nano-silica for enhanced oil recovery and stability of the injected fluid. To prepare a stable solution for injection, different concentrations of HPAM, nanosilica, salt and water were tested and the best combination of materials was obtained. It was found that the addition of a surfactant is needed to control suspension stability. The results of stability tests indicate that salt is main cause of instability of nano-suspensions. At high salinity single-valence ions show effects similar to bivalence ions on the stability of nano-suspensions. SDS can adsorb onto nano-silica particles and supercharge the interface to stabilize the nano-suspensions. Stable fluid was injected into a strongly oil-wet five-spot glass micromodel saturated with heavy oil and image processing was applied to analyze the displacement mechanisms and calculate the efficiency of each flooding test. The viscosity was measured for precise analysis of the experimental data. The oil recovery factor after one pore volume of injected fluid indicates that the ultimate oil recovery improved in the presence of nanosilica particles, which increased the viscosity of the injected fluid and altered the wettability of the pore walls. Nanoparticles appear to have the ability to change the wettability to water-wet in some portions of the micromodel. Measurements showed that nanosilica particles did not change the IFT between the crude oil and injected fluid.