Design And Application Reserch Of Three-phase Separator For Wellstream Enhanced By Electric Field Pre-separation

With the advent of the tertiary enhanced oil recovery in some oilfields domestically and overseas,the wellstream fluid of these oilfields witness constantly rising water content and gradually complicated qualities,which results in a series of increasingly prominent problems including the ability decline of the three-phase separator,the electric field collapse in the electric dehydrator and etc.Thus,developing electric field enhanced three-phase separators to improve the pre-water separation capacity for wellstream fluid can find more expansive engineering application and more significant academic research values.Firstly,the thesis analyzes the composition of the liquid sample in Shengli Oilfield to ascertain its basic physical parameters.And the Anton Paar MCR302 electrorheological instrument was used to analyze viscosity-temperature characteristics,rheological properties and kinetic stability characteristics of samples.The experimental data were fitted for a regression equation.A static experiment device equipped with insulated electrodes was designed to explore the electric field demulsification characteristics of crude oil emulsion.And the results shows that the treatment efficiency is 73%at the optimum electric field parameter of 1.29kV/cm and 2 kHz.Secondly,in the case of replacing crude oil by kerosene to prepare simulated emulsion,the static experiment with insulated electrodes was conducted again leading to a conclusion that the optimal electric field parameter combination is 5kV/3kHz and the water content should be less than 50%.Then,based on the principle of eletrocoagulation,a static experimental device equipped with metal electrodes was designed to conduct electric field demulsification experiments.And the results indicated that the optimal electric field parameter combination is65V/2kHz and the water content should be greater than 50%.Afterwards,an indoor dynamic experimental system was constructed mainly composing of a small horizontal separator and two electrode assemblies,which were designed following the rules of making Reynolds number equal and making electric field strength similar.In the case of installing a small insulated electrode assembly,W/O simulated emulsions with water content 20%was adopted to conduct experiment.In the case of installing a small metal electrode assembly,W/O simulated emulsions with water content 90%was adopted to conduct experimen.And it's oberserved that both circumstances show outstanding separation efficiency under specific combinations of electric field parameters.In the following part,a electric field enhanced three-phase separator medium test device with a handling capacity of 240m~3/d was designed and manufactured to run a field test at Shengli Oilfield 106 Platform.The results show that the optimal electric field parameters are 7kV,2kHz,and the water content of the separator oil outlet is reduced from 20%to 4%.Finally,engineering amplification applications was discussed.More concretely,the tank size model for the F4000 three-phase separator was established.Two electrode assemblies with different structural and electric field parameters were designed.The structural parameters were optimized by ANSYS MAXWELL numerical simulation software.Its optimal installation position inside the three-phase separator was delved.This thesis studied the electrostatic demulsification characteristics of two emulsified type of production fluids from various aspects.The advantages and potentials of electric field synergy in improving the efficiency of three-phase separator processing are verified.It has laid a solid foundation for efficient treatment of high water-containing oil well production fluid.