Research On Scale Prevention And Removal Technology For Oilfield Based On Ultrasonic And Electromagnetic

As an important means to enhanced oil recovery and maintain formation pressure, waterflooding has been widely used in the domestic and overseas oilfields. In recent years, with theongoing process of water flooding, scaling problem of water injection strata, oil wells andsurface gathering system becomes more and more serious; oilfield scaling problem hasattracted more and more attention. This paper presents a new anti-scaling and descalingtechnology based on ultrasonic-electromagnetic coordination field. This method combinesultrasonic and electromagnetic; it has advantages of low cost, wide applicable range, notcause environmental pollution, etc. At the same time this method can solve the problem thateffect of single physical field on the chemical and physical properties of water is small andanti-scaling and descaling effect is not obvious.Firstly, this article studies the mechanism of ultrasonic and electromagnetic anti-scalingand descaling, analyzes the factors affecting effects of ultrasonic and electromagnetic scaleprevention and removal. Then uses MATLAB and ANSYS do the modeling and simulation toget the best parameters and conditions of ultrasound and electromagnetic scale prevention andremoval. On this basis studies the synergistic mechanism of ultrasound-electromagnetic.Power supply system is the core of t ultrasonic-electromagnetic scale prevention andremoval device, this paper uses TMS320LF2407DSP as control chip, according to theworking principle of ultrasonic-electromagnetic power supply and load characteristic,completes the design of the power supply:(1) Rectifier part of the main circuit adopts the chopper-type rectifying circuit structure;High frequency part adopts the cascade multilevel inverter structure, by controlling switchangles of cascade units, realizes minimum total harmonic content while eliminating lowfrequency harmonic, simulation model is set up to prove the accuracy of this method; (2) Frequency tracking adopts variable step length DPLL method, through changing theworking frequency of the inverter to implement;(3) Power controlling adopts incremental PI regulating method, by adjusting the chopperswitch tube duty ratios to implement;(4) Designs the related sampling circuit, RMS conversion circuit, drive circuit andprotection circuit, etc;(5) Under the CCS environment, completes the PWM driver, frequency tracking, PIregulation related programs.Studies the impedance characteristic of the ultrasonic transducer, designs the dynamicmatching scheme based on magnetic flux controlling adjustable reactor. Simulationexperimental results show that by changing the injection current of the reactor secondary sidecan realize dynamic matching of transducer, under the assist of phase-locked loop can realizethe consistent of system resonance frequency and the transducer series resonance frequency,also reduces the harmonic content of load current.Finally, completes the3units7levels inverter, the output voltage waveform quality isgood, suitable for high frequency high power condition. Scale prevention and removalexperiments of ultrasonic, electromagnetic and ultrasonic-electromagnetic mixed field havebeen done, the experiment results show that ultrasonic and electromagnetic synergy cangreatly increased the anti-scaling and descaling effect, the result is better than a singlephysical field.