| At present,many large oil fields are in the stage of both high rate of water content and high recovery percentage of OOIP(original oil in-place).Enhanced Oil Recovery method has become an effective means to increase production.Polymer-surfactant flooding has become one of the main displacement methods owing to its obvious effect on EOR.But there are still some issues.Polymer-surfactant flooding has a hige cost,high risk and it’s difficult to realize field conduction.There are still a lot of polymers and surfactants in the formation after Polymer-surfactant flooding.To make full use of these polymers and surfactants,we can reduce the cost of production greatly.In view of the reservoir stratum condition of Gangxi-3 Oilfield,this paper proposes that recycle the polymers and surfactants detained in the reservoir stratum by injecting polymer flocculant、fixing agent and surfactant replacement agent.The author finishes the sedimentation experiment,plugging experiment,sand filling tube displacement experiment and rheology tests,and selects the treatment agents go for Gangxi-3 Oilfield,including the polymer flocculant SD-401 and fixing agent ALC(aluminium citrate),and does a optimization on the injection parameters.The best ratio of the two parts is determined through the laboratory oil displacement experiment,and form a optimum scheme of chemical displacing injection.In view of the way of the surfactants detained in the reservoir,this paper proposes a experiment scheme that injecting a replacing agentsodium polyphosphate.Reduce the adsorbing capacity of BHS-01,and make a desorption of parts of BHS-01 adsorbed in the stratum through the competitive adsorption between sodium polyphosphate and BHS-01,to achieve the recycling aim,and parameters of displacing agent injection are optimized.This paper forms a complete set of technology scheme of the recycle of the polymers and surfactants after the polymer-surfactant flooding. |
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