Study On Cleaning Technology Of Inner Wall Of Tubing Based On Cavitating Jet

During the exploitation of gas fields,the oil composition,pressure,temperature.etc are changing,there easily appear scaling and wax deposition in the inner wall of oil pipe and so on,which will bring adverse effects to production and even lead to stop well and suspend production.There are many ways to clean the inner wall of oil pipe,and cavitation water jet cleaning can stand out in many cleaning methods because of its low working pressure,strong impact force,economic and environmental protection,high efficiency.etc advantages.It combined with water jet technology and cavitation,taking advantage of high temperature and high pressure shock wave produced by broken cavitation bubbles to enhance the effect of jet hitting.In a bid to get cavitation nozzle sutible for inner wall of oil pipe of the inner diameter is 62 mm cleaning with good performance,the optimization of the nozzle structure parameters are obtained while CFD numerical simulation is based on the design method of orthogonal test are adopted,regarding cylindrical length,diffusion length,the diffusion angle and the target distance as the test factors,hitting force and the effective hitting radius as the test index,apply ICEM software to construct three-dimensional model of the nozzle and divide the grid,and proceed grid independent analysis,adopt FLUENT software to calculate the numerical simulation on the flow field,and the turbulence model k-ε,the Mixture mixed model,Zwart-Gerber—Belamri cavitation model are applied to numerically simulate the internal flow field each group of combination of cavitation nozzle structural parameters,through the range analysis and variance analysis,the optimum structural parameters of cavitation nozzles are obtained.After the best cavitation single nozzle structure is determined,comparing the performance between cavitation nozzles and ordinary nozzles,which proves the performance of cavitation nozzles is better than that of ordinary nozzles.Numerically simulate the internal flow field of cavitation single cavitation nozzles,and obtain its flow field characteristics.Number of injector in the whole nozzle is four.Under the condition that which can ensure the cleaning effect and improve efficiency,numerical simulation analy is applied for whole cavitation nozzle to obtain the distribution law of hitting force and effective hitting area.The test stand of water jet pipeline cleaning is designed for verifying the correction of the simulation results.While proceedinging Orthogonal test,use pressure sensors to get jet force of cavitation nozzle,and then compare the measured value of the hitting force and the simulated one,and demonstrate that the experimental result is consistent with the simulation result.;with aluminum piece as a jetting sample in cavitation nozzle impact test,and adopt electronic balance to measure quality loss before and after hitting,comparison of mass loss caused by cavitation nozzles and ordinary nozzles.The whole cavitation nozzle is used to clean inner wall of oil pipe,observing changes in the surface of inner wall of the tubing before and after cleaning,which is proved that the cleaning effect of the cavitation nozzle designed in this paper is remarkable.The research result in this paper provides the theoretical foundation and scientific basis for widespread application of cavitating water jet cleaning,which can provide technical support for improving tubing cleaning technology and remanufacturing technology and reducing the cost of oilfield exploitation.