Research On Selective Profile Control And Water Plugging Technology In Polymer Breakthrough Wells On Block J16

In combination with geological and development conditions of oil reservoir in Block J16,crossflow mechanism of and the corresponding influence factors on polymers were studied.On the basis of sufficiently utilizing masses of underground residual polymers,the principle of sewage purification by purifier commonly adopted for sewage treatment in oil fields was applied to study and optimize kinds,dosage,injection modes and slug size,etc.of new cationic plugging agents.To be specific,the principle is that a flocculation reaction can take place between cationic flocculant and polymers.Static experimental results show:when concentrations of polymers were equal to 100,500,1000 and 1500mg/L respectively,optimum concentrations of plugging agents 1,2 and 4 were 0.1%,0.3%,0.5% and 1% correspondingly,by contrast,plugging agents 1,2 and 4 all generate favorable coagulation effects as far as 7 cationic plugging agents selected are concerned when concentrations of polymers did not exceed 1500mg/L.Dynamic experimental results show:cationic plugging agents 1,2 and 4 could all react with polymers in the artificial core so as to play a role of postponing the polymer breakthrough time,reducing the peak concentration of polymers,lowering the time-to-Peak force for polymers and improving the initial polymer injection pressure.In addition,regarding an identical plugging agent,the higher the injection concentration and the injection rate were,the larger the injection pressure difference would be.As a consequence,the initial polymer breakthrough time was further delayed and the associated peak concentration also became much lower.Nevertheless,considering that the amount of polymers was definite,the peak concentration declines at a slower pace after increases in injection concentration and rate reached a certain degree.The stemming ratio went beyond 96.6% in the subsequent core plugging effect experiment,which signified that the plugging system had a good erosion resistance property in the rock core.So experimental results suggested that the injection concentration of plugging agent and the injecting slug should be greater than 0.6% and 0.5PV separately.