Development And Application Of Electric Dehydration Flow Evaluation Device

In oil field production,the electric dehydrator has become the most widely-used oil-water separation device for its low energy consumption,high efficiency and wide range.However,as a result of oil field development,especially the utilization of tertiary recovery,the efficiency of the equipment is getting lower and its stability is getting worse.Therefore,it is necessary to optimize the operating parameters for different emulsions based on performance evaluation and stability analysis of the electric dehydrator.Skid-mounted emulsion preparation device and electric dehydration device are well designed and manufactured.Based on the specifications,the overall size and layout drawing of the skid-mounted devices are settled,as well as every other parts including the coated stock tank,mixing system,heating system,control system and pipelines.Also,the tank and pipelines are coated with heating wires and insulating layer.The designing and manufacturing of the electric dehydration device are based on oil field investigations.The designing include but not limited to the following parts: the overall structure and size of electric dehydration device and the main shell,liquid distributor and collector tube,the structure and type of electrode,and the material of electrode end cap.The effects of water content,shear rate and temperature on droplet size and distribution pattern are well investigated.Results show that emulsions with long emulsifying time,large shear rate,low temperature and low water content is more stable,and a more evenly distribution of the dispersed phase.The research of indoor experiment on droplet coalescence and separation characteristics mainly bases on electric field parameters and operation parameters.Experimental results show that electric field strength is the key factor affecting electrostatic coalescence,where the critical electric field strength of heavy oil is lower than that of medium oil.Optimal frequency exists in the coalescence process,to sum up,the optimal frequency is between 50 and 100 Hz.When the water content is low,the exposure time plays a leading role.While water content is above 20%,electric field force becomes the leading factor and thus the effect of electric field intensity gets stronger correspondingly.With the increase of temperature,electrostatic coalescence works better,and he electric field strength for electro-dispersion decreases as well.Oil-water separation efficiency basically fit withthe droplet size varation.The water oil separation efficiency increases with the increase of plate voltage,water content and temperature.Electrode voltage is dominant factor affecting energy consumption,the energy consumption of the bare electrode barely change with frequency.The energy consumption increases with the increase of water content and temperature,and the effect of water content counts more than that of the temperature.The energy consumption of the bare electrode utilized in the experiment is much larger than that of the VIEC and CEC insulation layer under the same conditions.To sum up,the conclusions obtained in this paper are as follows: 1)the efficiency of oil-water separation increases with the increasing electric field strength,temperature and electric field exposure time;2)there is a optimal frequency in the coalescence process;3)the effect of electric field strength on oil-water separation counts more than that of the frequency.