Study Of Water Medium Dispersible Type Polyacrylamide Emulsion Profile Control Technique Used In Offshore Oilfield

Based on the developing and building characteristics of offshore oilfield, such as limited working volume of the platform, easy to be effected by the unfavorable weather, very rigid requirement about safety and environment, short of fresh water. A novel seawater based insant dissolving profile control system was developed, which is friendly to the environment. The water medium dispersible type polyacrylamide emulsion was used as viscosifier, and the water soluble phenol formaldehyde resin was used as crosslinker. Through Investigating the effect of polymer concentration, crosslinker concentration, temperature, salinity and pH value on the performance of the profile control system. The formula and usable range of the profile control system was be optimized: the ideal concentration of the emulsion P-1 is 1000mg·L^-1～6000mg·L^-1. The satisfactory concentration of the resol SG-3 is 1250mg·L^-1～3000mg·L^-1, The gelling time can be changed from 48h to 192h. The gel strength is -0.06MPa～-0.095MPa. The temperature range is 50℃～85℃. The highest salinity must be less than 80000mg·L^-1 for Na+. The pH range is 3～11. Evaluate the dissolving performance and the viscosifying action of the profile control system. From the lab experiment, we can conclude that at normal temperature the emulsion could dissolved at about 15～20 min. The process of online profile control in offshore oilfield was designed, and the jet mixer and static mixer were designed and manufactured. The online profile control process was simulated in the laboratory. From the test, we can conclude that when the concentration of polymer is less than 0.5%, the polymer and water could mixed sufficiently in 10～15min. It could meet the need of online building. A pilot test was runned in ChengDao oilfield CB1B-6, and the building effect was tracked and evaluated. The water intake rate of main water intake layers Ng41 and Ng42 declined form 82.4% to 65.8%. and the water injecting pressure increased from 5.6MPa to 7.2MPa. The water cut of the correspondent oil well decline about 4.1%. Up to april of 2009, the accumulated increased oil production is about 2000t.