Research On Techniques Of Polymer Injection Wells Integration Plug Removal

Polymer flood has been one of the most promising tertiary oil production methods, which possesses characters of enhancing recovery efficiency and economic benefit to a great extent. Daqing oilfield has entered into industrialized popularization application sting and achieved better effects of increasing oil and decreasing water. But along with the increasing injection volume of polymer, Under injection situations such as intermittent injection or short of injection allocation for it's high injection pressure are highlighting increasingly, which affect polymer flood effects seriously. Aiming at these problems, conventional hydraulic fracture and chemical plug removal have been applied in field, but it can't solve the short valid period radically although some effects have been made. Lacking systematic analysis that causes under injection of polymer injection wells is the main reason. The investigational of plugging reason plugging extent plugging rule don't make progress thoroughly even if the reasons of under injection has been realized more; Lacking a suit of effective plugging diagnosis and treatment optimizing technology result in a blind measure. It is imperative that short valid period problem after low permeability reservoir was reconstructed must be solved.Base on analysis of the reason of forming plug in polymer injection wells, this paper compares the capability of removing plug of some different plug removing agent through laboratory test and theory analysis, a better plug removing agent and a plug removal technique is obtained. The test choose agent such as, NaClO, (NH₄) S₂O₈, FeSO₄, Na₂C₂O₆, NaBO₃ to degradation the polymer gel, through compare the viscosity before degradation and after degradation to determine the plug removing agent which can remove the plug in polymer injection wells. Test results show that H₂O₂ have stronger capability of removing plug than others at different concentration and different temperature, it can effectively break the polyacrylamide gel rapidly, and the viscosity of the post-breaking residual fluid is low. The optimized agent can effectively degradation the plugging bring from the polymer injection wells rapidly, it showed that H₂O₂ can reach the demand reduce viscosity and remove plug in polymer injection wells.