Optimization analysis of structure parameters of downhole vortex tool based on CFD and orthogonal studies

摘要

Liquid loading is one of the most serious problems in the gas wells with low pressure and production. It limits the production severely, due to the high cost of other deliquification technologies. The downhole vortex tool is an economic and efficient way to alleviate the liquid loading, but the optimal efficiency conditions still not clearly. In this paper, gas-liquid two-phase flow passing through a downhole vortex tool is studied by numerical simulation to optimize the structural parameters (Helix angle, helix height, helix width) and operating envelope (superficial gas velocity and superficial gas velocity) of the vortex tool. The Euler-Euler approach and Reynolds stress turbulence model are used to calculate the vortex field. The experimental results show that the pressure gradient downstream of vortex tool agrees well with the numerical results. An orthogonal design method was used to evaluate the performance of the vortex tool with different structural and operating parameters. The range analysis results show that the optimal combination is A(2)B(2)C(3)D(5)E(5) (alpha = 45 degrees, H = 6 mm, h = 15 mm, v(sg) = 18 m/s, v(sl) = 0.1 m/s), with the impact sensitively intensity to evaluate index of each factor as follows: A > E > B > D > C. The effective operating envelope of vortex tool is when superficial gas velocity range from 9 m/s to 16 m/s. The pressure gradient downstream of optimal tool decreased by about 20.3% compared to the original tool at the maximum value point.