Study On The Change Rule Of Liquid Film Thickness Of Horizontal Pipe Wall Under The Action Of Vortex Tool

With the development of natural gas field,liquid loading of gas wells is inevitable.If the problem of liquid loading in gas wells is not found in time and effective drainage measures are taken,not only the gas reservoir production cycle will be shortened,but also the formation will be polluted and harmed.Vortex tools are very promising downhole drainage technology,but this technology is still in its infancy at present.It is necessary to deepen the research on the mechanism and effect of vortex tools,in order to better guide the investment and use of this technology in China's gas fields.In this paper,a theoretical model for calculating liquid film thickness of horizontal pipe wall in different stages of gas-liquid two-phase flow under the action of vortex tools is established.Based on the actual physical phenomena,the governing equations of the spiral groove section of vortex tools,the free shear swirl section and the annular flow section of the gas-liquid two-phase in the horizontal pipe are established.According to the flow characteristics of different stages,reasonable boundary conditions are assumed.By analyzing the order of magnitude,ignoring the high-order infinitesimal,the model is simplified.Based on the surface force balance conditions and mass transfer conditions at different flow stages of gas-liquid two phase flow,the liquid film thickness was solved by the control equation.Finally,the theoretical calculation model of the liquid film thickness at different flow stages of gas-liquid two phase flow was obtained.Designed two parallel conductance probe-sensor with adjustable depth.The liquid film thickness of different liquid film development stages in the horizontal pipe after the installation of vortex tools were measured by laboratory experiments.It is found that the liquid film thickness of the spiral groove section of vortex tool changes periodically with the change of the spiral circumference angle,and the periodic variation of the liquid film thickness of the free shear swirl section is gradually weakened,and the liquid film thickness tend to be uniform in the annular flow stage.The liquid film thickness at the bottom of the horizontal pipe is higher than the liquid film thickness at the top of the pipe.By changing the gas phase and liquid phase speed,the variation of liquid film thickness in horizontal pipe under different working conditions was studied.It is found that with the increase of gas phase speed,the liquid film thickness in the horizontal pipe is attenuated,and the degree of attenuation is positively correlated with the increase of gas phase speed.With the increase of liquid phase speed,the liquid film thickness in the horizontal pipe increased,and the degree of increase was positively correlated with the increase of liquid phase speed.By comparing the changes of liquid film thickness in different liquid film development stages in the horizontal pipe,it is found that the liquid film thickness gradually decreases with the increase of the axial movement distance of the liquid film,but the attenuation amplitude of the different liquid film development stages is different.