Structure Design And Performance Research Of Adjustable Constant Flow Water Injection Blanking Plug

With the development of high water excavated old oildfields in China,which have many problems such as residual oil scattered,prominent contradictions among,with and plane,over injection under injection,invalid cycle serious,increasing environmental pressure and so on.So the third generation of water drive fine potential tapping technology which takes fine layering technology as its core has been developed in major old fields at present.But when the layer segment is subdivided to more than 7 segments,the pressure difference between the segments will increase,the interlayer interference will be serious,and the difficulty of measurement and adjustment and the workload will increase exponentially.The mechanical eccentric constant current water distribution plug can make the water injection quantity not change with the water injection pressure,formation pressure and the water injection condition of other intervals of the well.It can reduce the workload of measurement and adjustment to a certain extent,and has low cost,and has been well applied in layered water injection technology.However,when the injection flow is changed,the constant current can not be adjusted,so it is necessary to fish and replace the water nozzle manually to match the flow again.It is difficult for the existing plug to solve the problem of increasing the difficulty of measurement and adjustment when the subdivision interval is increased,this paper developed a mechanical adjustable constant flow water injection plug in the confined space.A new type of central rod type adjustable constant current water injection plug structure is designed,which can realize constant current when the water injection condition changes,and can realize constant current regulation by controlling the opening of the regulating valve through the rotation of the fishing head.The flow field characteristics of the new type adjustable constant current plug were simulated,and the distribution law of the pressure and velocity field and the stress of the valve core were obtained.Based on the results of the numerical simulation,the opening of the adjustable constant flow control valve is matched,and the theoretical calculation formulas of the flow rate,the opening of the adjustable valve and the spring stiffness are established.The parameter matching of the adjustable constant flow water injection plug is completed.At the same time,indoor experiments are carried out.The results show that under the condition of 0.5Mpa-0.4Mpa pressure difference,it can achieve constant flow and adjustable flow within 45m3/d-60m3/d range.The new type of mechanical adjustable constant flow water injection plug can reduce the times of the plug,reduce the cost of water injection,improve the efficiency of measurement and adjustment,and effectively solve the bottleneck of the multi-layer subdivision layer water injection technology.