Multi-parameter Optimization for Downhole Gas Compression System

Downhole gas compression (DGC) is a novel artificial lift technology for gas wells since it can increase the gas flow rate and decrease the abandonment pressure. The downhole gas compression realizes the gas pressurization by installing the downhole gas compression device at the bottom of the well. The process parameters of DGC directly affect the application effect. This article introduced the multi-parameter optimization method for DGC system. Three factors, the device installation depth, the tubing inner diameter and the compression ratio, were selected as the optimization parameters. Two evaluation indexes, the gas flow rate and the abandonment pressure, were considered simultaneously for the optimization. Based on the orthogonal experimental design method, a L₁₆(4³) table was implemented to improve the optimization efficiency. The evaluation indexes were obtained based on the results of node analysis. The range analysis was performed to get the optimal combinations of process parameters and the influence degree of each process parameter on evaluation indexes were obtained. The synthetic analysis was conducted to get the multi-parameter optimized combination. The verified simulations were conducted to validate the proposed optimization. The simulated results indicated that the optimal process combination achieved better gas flow rate and lower abandonment pressure at the same time. The comprehensive optimization of two evaluation indexes can be achieved and it provides a potential method for DGC application optimization.