Joint adjustment and optimization on the operation parameters of gas lift-electric submersible pump combined lifting in oil wells

In the process of gas lift-electric submersible pump combined lifting under a given production target, the production is discordant due to low-efficiency working conditions. To solve this problem, the coupling mathematic model of gas lift and electric submersible pump lift was established after the inflow performance of oil well, the multi-phase flow characteristics of wellbore, the kinematics and dynamic characteristics of lifting process and their mutual energy effect were investigated. Then, the working conditions of oil well were analyzed by means of node analysis method. Thus, the optimization and joint adjustment method for the operation parameters of gas lift-electric submersible pump combined lifting to reach different production targets was developed, and the optimal operation parameters of electric submersible pump and gas lift under different production targets were provided. The calculation results show that when low-efficiency working condition occurs in the gas lift-electric submersible pump combined lifting system, the working condition can be analyzed using the acquired production performance data. When the production rate changes, the decision on operation parameter adjustment is made based on the quantitative analysis result of the working condition. In this way, the frequency-gas injection joint adjustment scheme of gas lift-electric submersible pump well is prepared scientifically, and oil reservoir, well and equipment are coordinated. And in the operation with immovable string, the combined-lifting oil well can run efficiently.