The Matching Design Of Downhole Oil-water Separation System With Electric Submersible Pump And Hydrocyclone

Now,with the difficulty of exploting oil wells becoming larger and larger, water flooding technique is used widely.The using of this technique brings a series of problems,such as the problem of dealing with sewage water on ground, the problem of wasting energy resources and so on. On this situation, the downhole oil-water separation technique developes.The essence of this technique is to realize separating oil and water,lifting up oil of low water percentage,injecting water in the one oil well and in the same time.At the present, the downhole oil-water system has many styles. The downhole oil-water separation system with submersible pump and hydrocyclone is chosen in this paper. This systerm adopts the inverted submersible pump with double flow channel, which solves the problem of running bypass pipe before. And,this system applies double series hydrocyclone with tri-crossed flow channel, which improves the separating rate of oil and water. Besides,this system adopts the inverted protector.Aiming at this system,the pipe string is designed in this paper. The units can be guaranteed to reach downhole, using the following tools,such as release sub,packer,seat for improving pressure,inverse seat,sealing intubate,sliding side door and so on.Now,the downhole oil-water separation technique is still in the stage of experiment,the reason of which is that it is difficult to realize lifting oil and injecting water in the same time.In view of this,one set of method is studied to make units realize lifting and injecting simultaneously.Appling downhole inflow performance relation,the relation between bottom-hole pressure and oil production is obtained. Basing on the Orkiszeswki's method,the pressure drop of multiphase flow in well bore is calculated. Meanwhile,adopting the method of nodal system analysis,the pressure and flow rate are pushed out in every position of well bore.For realizing the matching of pressure and flow rate,the chokes are used after underflow or overflow port of hydrocyclone.According to the pressure drop characteristics of choke,the diameters of chokes can be calculated.In one word,the method and steps are achieved for matching design of downhole units in this paper.At the same time, ont set of method is established to inspect downhole parameters according to the datas tested on ground,by which,the working condition of wellbore can be adjusted and optimized by changing the parameters in wellhead.Using the above theory analysis, ont software is compiled.This software can be used to match units and inspect downhole parameters when the downhole oil-water separation system is applied.The software provides certain theory basis for the using of downhole oil-water separation system in the future.