Research On Downhole Drainage Gas Collection Device For Supersonic Atomization

At present,the biggest problem limiting natural gas production is the accumulation of liquid at the bottom of gas wells,and drainage gas production is an effective extraction technology.Gas well production and mining technology generally has the characteristics of large equipment investment,complex process and unstable effect.Based on the background of low-pressure and low-yield gas reservoir exploitation in the later stage of gas well exploitation,this paper proposes a controllable ultrasonic atomization drainage mining technology based on ultrasonic atomization drainage mining technology,and independently designs a downhole supersonic atomization drainage nozzle to realize the use of formation gas reservoir energy for drainage.In this paper,the process scheme design of supersonic atomization drainage gas collection technology is carried out,the supersonic atomization nozzle is designed based on supersonic atomization technology,the flow law in the supersonic atomization nozzle of the core component is studied,and according to the characteristics of the nozzle,the flow field simulation is carried out by Fluent,which verifies the feasibility of supersonic atomization of the nozzle,and simulates the flow of the nozzle to obtain the trajectory distribution of atomized particles.The influence of gas-liquid phase parameters and structural parameters on the diameter of atomized particles was analyzed,and finally the size of the largest droplet was studied.It is found that the diameter of the atomized droplets of the designed nebulizer is smaller than the diameter of the portable droplets,and can be completely carried out of the wellbore.Secondly,a set of test system and atomizer model were designed for experimental research,using orthogonal design method,the average particle size(SMD)distribution characteristics of Salter were selected as the evaluation index,the gas-liquid phase parameters and structural parameters were optimized,and the influence of experimental parameters on the atomization effect was discussed through range analysis,and the optimal parameter combination A4B1C1D2 was obtained,and then the model was verified according to the optimal atomization combination,and the model verification experimental results showed that the structural parameters and gas-liquid phase parameters preferred by orthogonal experiments were reasonable.The atomization effect is still the best,and the particle size of the droplets obtained by the experiment is smaller than the minimum critical liquid-carrying diameter of the designed atomizer after atomization,which can be carried out of the wellbore,and can be freely combined with the gas-liquid phase parameters and structural parameters to adapt to the complex and changeable gas-liquid flow state of the downhole.The experimental results were compared with the numerical simulation results,and the influence of fluid parameters and structural parameters on the particle size of droplets was compared.The comparative results show that the variation of droplet particle size with gasliquid phase parameters in the experimental results is consistent with the numerical simulation.In the experimental study,the variation of droplet size with structural parameters was highly consistent with the numerical simulation analysis results,indicating that the experimental results were reliable.Finally,on the self-constructed test platform,the result parameters of the atomization test are obtained,and the correlation analysis of the test results is carried out.On the basis of the experimental data and sensitivity analysis,SPSS and Matlab were used to construct a multiple nonlinear regression atomization model,after calculation,the coefficient of determination of the atomization model R2 was 0.973,and the average relative error between the prediction result and the experimental value was 17.36% by the fitted atomization model,and the error was small,the model was established more accurately,and the size of the droplet particles under various conditions could be predicted,which had certain significance for guiding the atomization nozzle drainage and gas production.In this paper,a series of studies on supersonic atomization mining technology are carried out,which have certain significance for improving the wellbore liquid carrying efficiency and drainage efficiency,and have certain reference significance for the development of atomization mining technology in the future.