Abstract: In order to solve the problems of high flow resistance and difficulties in production of super-heavy oil in low-permeability area during steam stimulation and steam flooding, in-situ catalytic reforming and viscosity reduction technology for super-heavy oil in low-permeability area was proposed. Reactor method and physical model experiment method were used to select high-efficiency in-situ reforming catalysts, and the catalyst injection method was studied. Five types of catalysts and their reforming conditions were selected. The study showed that: when organozinc was used as catalyst, the amount of catalyst was 0.1%, the water content of heavy oil was 50%, the super-heavy oil showed a better performance in reforming and viscosity reduction; the effect of physical model experiment method on in-situ catalytic reforming and viscosity reduction was better than that of reactor method; under conditions that the water content of heavy oil was 50%, the amount of catalyst was 0.1%, the reaction temperature was 240 ℃, the back pressure of sand filling pipe was 8 to 10 MPa and the reaction time was 24 h, the viscosity of heavy oil was decreased to 54 260 mPa·s from 145 000 mPa·s, and the viscosity reduction rate was 62.58%; the density and acid value of the heavy oil reformed by physical model experiment were decreased, the content of heavy components (colloid and asphaltene) was decreased by 10.85 %, and the fractions before 300 ℃ and 500 ℃ were increased by 6.75% and 17.29%, respectively. At 240℃ and 10 MPa, the self-made biomass-based profile control agent was used to block the dominant seepage channel, and the catalyst was injected into the low-permeability sand-packed pipe and then water flooded. The viscosity of the reformed heavy oil was reduced to 68 450 mPa·s, the viscosity reduction rate was 52.79%, the process flow resistance was reduced by 19.74%, the recovery rate reached 95.22%, and the comprehensive recovery rate of heavy oil was increased from 46.94% to 85.13%. The method provides references for in-situ catalytic reforming and viscosity reduction of heavy oil in low-permeability areas to enhance the oil recovery in the process of steam stimulation and steam flooding of super-heavy oil.

Key words: super-heavy oil, catalyst, in-situ catalytic reforming, oil solubility, steam stimulation, steam flooding, enhanced oil recovery