Structure Optimization Of An Inner Cone Type Oil-water Separation Cyclone Based On CFD

In the context of most domestic oilfield production gradually entering the medium to high water content stage,the scale of oilfield surface water treatment equipment is expanding and the treatment cost is increasing year by year.Under such circumstances,oil-water separation cyclones are ideal for downhole oil-water separation equipment due to their low cost and high separation efficiency.However,existing research shows that the double tangential inlet structure of conventional oil-water separation cyclones is large in size and difficult to adapt to the downhole tubular space.In order to solve the practical application problems of conventional oil-water separation cyclone,an internal cone type oil-water separation cyclone is designed in this paper.Firstly,the internal oil-water separation process is analyzed by computational fluid dynamics(CFD)method;then the influence of structural parameters on the separation performance of the internal cone type oil-water separation cyclone is studied by single factor method;finally,the structural parameters of the internal cone type oil-water separation cyclone are optimized by orthogonal test method.Finally,the structural parameters of the internal cone type oil-water separation cyclone are optimized by using orthogonal test method,which lays a solid theoretical foundation for the practical engineering application of the internal cone type oil-water separation cyclone for downhole oil-water pre-separation and co-well reinjection.The following main results were achieved in this paper:1.CFD method is used to study the structure scheme of single cone oil-water separation cyclone and internal cone oil-water separation cyclone.Through comparative analysis,it was concluded that the separation performance of the internal cone type oil-water separation cyclone was better,so the internal cone type oil-water separation cyclone was finally selected as the subsequent structure optimization research object.2.The main structural parameters of the internal cone type oil-water separation cyclone were analyzed by the single factor method,and the influence of each parameter on the separation performance of the internal cone type oil-water separation cyclone was investigated by CFD numerical simulation technology.The influence of structural parameters such as inner cone height,inner cone bottom diameter,cyclone chamber length,blade number,blade wrap angle on the bottom flow oil removal rate,overflow dewatering rate and pressure drop was obtained.3.The structure optimization study of the internal cone type oil-water separation cyclone is carried out by using the orthogonal test method,with the bottom flow oil removal rate,overflow dewatering rate and pressure drop as the evaluation indexes,and finally the optimization model 1 derived from the intuitive method of bottom flow oil removal rate is the optimal structure.The optimization results show that the influence of each factor on the bottom flow oil removal rate of internal cone type oilwater separation cyclone is in the following order: Inner cone height > number of blades > blade wrap angle > swirl cavity length > inner cone bottom diameter;compared with the initial model,the bottom flow oil removal rate of optimized model1 reaches 98.86%,an increase of 5.65%;the overflow dewatering rate reaches 79.09%,an increase of 13.76%,and the pressure drop decreases by 1.4 k Pa.The feasibility of optimization was confirmed.