Research On Hydrocyclone Used In Downhole Oil-water Separation Of Offshore Oil Field

In order to inject separated water in the well and produce oil to thesurface, downhole oil-water separator (DOWS) device uses hydrocyclones inthe well bottom to separate oil and water which are different in densities.DOWS are used in Caofeidian oil field, Alliance oil field and so on. Thestudy of hydrocyclone which is the core equipment of DOWS is at animitation stage at present in China. This is not reliable to change a structureparameter with experience when the problems appeared in the process ofproduction. Therefore, it is necessary to study the structure optimization andseparating property of the hydrocyclone. This subject focus on the core issueof hydrocyclone through the numerical simulation to optimize the structureparameters, and study the separation efficiency at different operatingparameters. At the same time, we build the laboratory, pick up theexperimental data and compared with the numerical simulated results in orderto test the validity of simulation.The diameter and other structure parameters of hydrocyclone werecalculated based on the data supplied by a marine oil field. Structureparameters were optimized with Fluent. According to the optimized structure parameters, the inlet flow, viscosity and specific gravity, which were effect theseparation efficiency of hydrocyclone, were analysed. The numericalsimulation results were contrasted with experimental data obtained from theexperiments.The internal flow field was the most reasonable when the diameter ofoverflow was5mm,the big cone angle was20°and the small cone angle was3°through the numerical simulation. To the hydrocyclone, the separationefficiency was accelerated with the increase of the inlet velocity in a certainrange. But the separation efficiency was decrease when the inlet velocity wasgreater than11m/s. The cyclone separation efficiency increased from61.1%to21.7%when the viscosity of the continuity increases from0.0013Pa s to0.013Pa s. The hydrocyclone lost the separation performance when thespecific gravity surpassed0.95.