1.中海石油中国有限公司天津分公司 天津 塘沽;2.东北石油大学 提高油气采收率教育部重点实验室 黑龙江 大庆
Aiming at the problems of rich heavy oil, serious heterogeneity and poor water drive development effect in Bohai reservoir, the effect of using particle diversion agent or heavy oil emulsifier alone to improve oil recovery is not ideal. Therefore, it is of great significance to study the performance of heavy oil emulsifier and particle diversion agent composite system. The performance of emulsifier, polymer microspheres and gel dispersions of heavy oil in LD5-2 heavy oil reservoir in Bohai Sea and the effect of liquid flow diversion were studied and analyzed by means of laboratory evaluation. The results show that the median initial particle size of polymer microspheres is 8.7～9.2 μm and the expansion ratio is 2.5～3.0. The dispersion of gelatin showed irregular morphology in vitro, and the effect of retarding swelling was not obvious. Adsorption of surfactant by steering agent particles reduces the effective content of heavy oil emulsifier and decreases the effect of emulsification and viscosity reduction, but the quality ratio of oil to viscosity reducing system still has good viscosity reduction effect in a certain range. Surfactant molecules are adsorbed on the surface of microspheres or gel dispersions in the binary system of "heavy oil emulsifier/particle diverter", resulting in electrostatic repulsion between particles, resulting in loose arrangement structure. Compared with using particle steering agent alone, the particle steering agent in the composite system has good shear resistance, injectability and deep profile control and displacement ability. For reservoirs with large channel or extra high permeability, granular diversion agents must be combined with strong gel to exert synergistic effect of micro and macro fluid diversion.