Study On Collaborative Plugging Removal And Increasing Injection Technology Of Polymer Injection Well In Jinzhou 93 Oilfield

Jinzhou 93 oilfield has carried out polymer flooding pilot test, whose apparent effect of increasing oil makes it an important mean of production performance. But every coin has two sides, part of polymer injection wells appeare reservoir plugging near wellbore which leads to the increasing of injection pressure and the decreasing of injection volume, unable to meet the demand of injection and affecting the overall effect of polymer flooding. Therefore, it is necessary to study the corresponding safe and efficient plugging removal technology for polymer injection wells according to the characteristics of offshore oilfield and the actual circumstance of Jinzhou 93 in order to restore reservoir permeability and low injection pressure, only by this, the technology of polymer flooding could be developted smoothly.This article firstly made plugging reason clear by detecting bottomhole contaminant and analysing factors affecting polymer flocculation and blocking. Then principal agent formula of lifting polymer blockage and inorganic blockage was determined by the polymer degradation experiment and minerals and fouling substances corrosion experiment. Under simulating the actual injection conditions, plugging experiment and plugging removal experiment were developed to make sure the best parameters and the variation law of polymer injection capacity after plugging removal, based on which period of validly plugging removal model was finally established. Research shows that, the synergistic degradation agent can degrade marine polymer down to 1.0 mPa?s, dissolution rate of downhole polymer pollutants sample is 85.8% and dissolution rate of solid blockage is 88.6%. Injecting the reservoir protection fluid can effectively prolong the valid period of polymer injection.