| As the development of the national oil and gas resources development,the utilization,and exploitation of low-permeability reservoirs and unconventional oil and gas resources are expanding and has become the pillar and driving force for the future energy and economic development of the world.China's onshore oil and gas exploration and development are also gradually expanding to the periphery.The proportion of non-self-spraying wells and non-selfblasting reservoirs,which are characterized by low pressure,low porosity and low permeability,also increases year by year in natural gas exploitation.For example: Changqing,Daqing,Xinjiang,Sichuan,Henan,Liaohe,Victory and other large oil and gas to "three low" as the characteristics of the development of reservoir input scale.In this kind of gas fields,gas wells are inevitable in the late stage of mining,and fluid accumulation will gradually reduce the production of gas wells and even shut down the wells.Vortex tools drainage gas production technology is the earliest by the United States put into trial production by China National Petroleum Corporation in recent years the introduction of new technologies in China.Therefore,this paper analyzes and studies the technology and working characteristics of the drainage and gas production of vortex tools,designs a self-sealing vortex drainage gas production tool and analyzes and optimizes the main parameters of the tool to adapt to different downhole conditions to improve the vortex tools Liquid carrying capacity.This paper mainly aims at the current unsatisfactory status of downhole vortex drainage and gas recovery tools in China.The purpose of this study is to improve the performance of the process.First of all,a new type of sealed eddy current drainage and gas recovery tool has been designed.Through the designed sealing unit,the volume loss of the tool is significantly reduced and the vortex tool extraction capacity is improved.Second,through theoretical research and numerical simulation methods,the flow state of the vortex tool in the tubing and the liquid carrying mechanism of the tool are studied.Having analyzed and compared the liquid-carrying performance of the vortex tool before and after sealing.The calculations show that the vortex tool can increase the flow rate of the two phases in the tubing by 17% and increase the cross-sectional hold-up rate of the wellbore by 13%.The effects of different working conditions and the main structural parameters of the tool on the drainage performance of vortex tools were studied separately.Calculate the liquid carrying capacity of the vortex tool under different parameters and the maximum velocity of the liquid phase in the river basin.Determined the main factors affecting the vortex tool's effectiveness.At last,based on the influence of the main structural parameters of the tool on the effect of drainage,the response surface methodology(RSM)and particle swarm optimization(PSO)were used to optimize the design of the vortex tool.Increases the tool's liquid carrying capacity by 16%.Through optimization,the tool parameter values for the best draining effect under different working conditions are determined to achieve the optimization of the vortex tool's drainage and gas recovery.It is of great significance to improve the efficiency of drainage and gas recovery of tools,extend the continuity of mining,and increase the recovery of natural gas. |
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