| Compared with the vertical well,horizontal well has the advantages of increasing the deflated area,increasing the production of single well,reducing the drilling of vertical well,and being economical.However,due to the special well structure and characteristics of horizontal wells,the drainage gas recovery method commonly used in vertical wells with good application effect is not suitable for horizontal wells,so it is necessary to research and promote the drainage gas recovery technology of horizontal wells.According to the idea that the vertical well vortex tool can generate gas-liquid two-phase swirl flow to improve the gas well drainage and recovery capacity,the horizontal well internal vortex tool is designed,which can be directly connected with the casing to run into the horizontal section of the horizontal well.After the natural gas enters the internal vortex tool,the gas-liquid two-phase flow state can be changed to improve the liquid carrying capacity.In order to solve the problem of liquid accumulation in horizontal wells,the structural parameter optimization and drainage effect of the internal vortex drainage gas recovery tool are studied in this paper.In order to accurately judge the fluid accumulation in horizontal wells,the gas-liquid interfacial tension,gas compression factor,droplet deformation parameters and drag coefficient in the critical fluid carrying flow model were modified.The improved critical fluid carrying flow model was verified by using production data from 30 gas wells,and its accuracy was proved.The dynamics analysis of liquid droplets and liquid films in the swirl field provides a theoretical basis for the analysis of gas-liquid two-phase flow in the post-swirl field with the internal vortex tool.In order to improve the liquid carrying capacity of gas well and the effect of internal vortex tool,the orthogonal test method was used to optimize the structural parameters of internal vortex tool,and the liquid carrying effect of the optimized internal vortex tool was analyzed.Based on the analysis of the effect of the internal vortex tool carrier in,using the theory of gas-liquid two phase flow fluid to flow through the internal vortex tool to study the gas-liquid two phase flow,with the analysis of level and mathematics such as variable separation method is established within the internal vortex tool application calculation model of drainage gas recovery.Numerical simulation was carried out on the two-phase flow after the internal vortex tool was used to analyze the attenuation law of the gas-liquid two-phase swirl flow after the tool was used.The accuracy of the mathematical model was verified by comparing the numerical simulation results with the theoretical model calculation results,so as to evaluate the effect of the internal vortex tool.In order to improve the calculation model of internal vortex tool application,the influence of well angle on the effect of internal vortex tool was fully considered,and the running series of internal vortex tool with different well positions were designed.According to the study,the importance of the structural parameters of the internal vortex tool on the drainage effect is as follows: swirl angle > swirl height > swirl width > swirl number,and the optimal structural parameters are determined as follows: The swirl angle is 60°,the swirl height is 20 mm,the swirl width is 4mm,and the number of swirl lines is 1.The internal vortex tool can change the flow track and flow state of gas-liquid two-phase flow and improve the liquid carrying capacity of gas well.The effect of the internal vortex tool decreases with the increase of distance.The field application design of internal vortex tool for 15 gas wells in actual production can provide a basis for optimizing the selection of internal vortex tool in practical application.The above results can provide theoretical guidance for the application of internal vortex tools in horizontal gas wells. |
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