Steam channeling control in the steam flooding of super heavy oil reservoirs, Shengli Oilfield

Abstract

In view of the severe steam channeling in the steam flooding of super heavy reservoir, lab experiment on steam channeling control were carried out. The combination of nitrogen foam and thermoset blocking agent was tested to seal steam channeling, in which thermoset blocking agent plugs big pore throats, while nitrogen foam adjusts steam absorption profile. The optimized foam formulation has a resistance factor of over 30 at 300 °C, can plug low oil saturation areas selectively, and applies to the plugging of high permeability zones in super-heavy oil reservoirs. Thermoset blocking agent, which would consolidate at 120 °C in 4 h and consolidate at 150 °C in 2 h, can provide effective plugging during dynamic steam flooding. The best steam channeling control mode was determined using parallel tube model. By the combination of nitrogen foam and thermoset blocking agent, the recovery rate is 5.7% higher than the application of nitrogen foam only, with the overall sweeping efficiency reaching up to 60.8%. In 2011, the mode was used in the steam flooding in Shan-56 reservoir. The water cut drops 10.2%, the wellhead temperature of producer drops more than 15 °C, the oil production of the well group increases over 28 tons per day, the valid period of a single cycle is up to 198 days, and the oil production increases 2 562 t, showing significant improvement in steam flooding. Key words: super heavy oil, steam flooding, nitrogen foam, thermoset blocking agent, steam channeling