Study and Application of Anionic and Cationic Polymers Alternative Injection for In-Depth Profile Control in Low Permeability Sandstone Reservoir

摘要

control technology referring to the alternative injection of anionic and cationic polymer for in-depth profile control in low permeability sandstone reservoir was proposed and developed when the oil wells were in high water cut stage. The adsorption equilibrium mass concentration of the cationic polymer is 1500 mg/l and the adsorption equilibrium time is about 8 hours, while the adsorption equilibrium mass concentration of the anionic polymer is 1000 mg/l and the adsorption equilibrium time is about 6 hours. The physical simulation experiment shows that anionic and cationic polymers alternative injection and prior injection of cationic polymer with high plugging capacity are better than the single polymer injection. The plugging capacity increases with the increase of injection rounds, the optimized injection round is no more than 3 times according to economic benefit. This technology is successfully applied in Shuangqian 6 well of Henan oilfield in June 2010. After treatment, the high permeability channel is effectively controlled, the water cut obviously decreased and the oil production increased, it is shown that this technology is a reliable and feasible technology and worthy to be widely applied in low permeability sandstone reservoir.