Study On Sustainable Plug Removal Technology Of Offshore Polymer Injection Wells

Polymer flooding has been proven significantly effective and economical in the offshore oil field. However, as the injected volume of polymer solutions increase, the inject pressure increase, makes it hard to inject enough polymer solution to drive crede oil and it is highly detrimental to enhance oil recovery efficiency. Therefore, On the basis of the literature review and analysis in the investigation, specific to SZ36-1 offshore oil field in Bohai bay, this paper investigated the mechanism of plug of polymer injection well and developed propariate plug removal agent. The main cognition and conclusion are as follows:(1) Due to the characristics of SZ36-1 formation and the limited space of platform, suspended solids and polymer glue will inevitably plug the injection well;(2) The well soluted polymer solution will not cause completed jam the injection well, but the apprerence of insoluable impurities will finally jam the injection well totally;(3) The plug of offshore polymer injection well is the compound of organics and inorganics, and those plugs mainly exist in the near well bore areas;(4) This paper estabilised a numerical simulation model to investigate the radius of polymer edge, the example show that the most contaminated zone of polymer adsorption is less than 25m;(5) On account of characteristics of injection well, this paper proposed a new chemical plug removal techlonogy:combination of oxidizer and acids and surfactant;(6) Selectd the most suitable oxidizer-SA-PR through experiments, it has strong ablity to decompose polymer plugs;(7) Developed a new acid system-InteAcid, it has strong ability to dissolve plugs and prevent secondary sediment;(8) Aimed at enhance stimulation and prolong period of validity, selected the best surfactant, it can decrease interfacial tension and increase flowability;(9) The numerical simulation indicate that the most suitable plug remove radius is 1.5-3m;(10) On the basis of experiments, take the special condition of offshore oilfield into consideration, the sequence of injection should be oxidizer to isolation fluid to preflush to treating acids to after flush to cleaning fluids;(11) The filed application vetifies the perfomace of compound plug removal agent is excellent. It is feasible and worthwhile to promote.Overall, the research of this paper completes the mechanism of plug of polymer injection and succefully developed highly effective plug removal agent.