Electric Submersible Pump Setting Depth Optimization- A Field Case Study

Abstract Well completion design consideration, in artificially-lifted wells, are typically governed by the philosophy of operators and dictated by the conditions and type of well and reservoir being produced. Fluid properties is also an important parameter to be considered in the design of the system. Typically, electric submersible pumps, ESP's are set close to the producing zone for different considerations of flow efficiency and well completion. This paper presents a field case study of optimizing ESP setting depth. The study was conducted on field actual case and considered the pump performance at different setting depth for certain well completion menu and different operational aspects of well integrity, etc. The main objective was to check the lowest setting point without jeopardizing ESP performance or violating well integrity/control mandates, and avoiding the potential vibration associated with multiphase flow. This is to reduce cost of cable, improve operating conditions without jeopardizing pump flow efficiency. Flow simulation of multiphase flow through the ESP was conducted to examine the gas volume fraction and total dynamic head to evaluate performance at different setting depth. Flow simulations are presented for the case study. Results indicated that fluid properties, completion design, production practices dictate the setting depth. Sensitivity runs were made for cases to cover the life cycle of the pump, including the changes water percentage, formation pressure, and flow different values pf productivity indices and pumping wellhead pressures. Operation practice may not sometimes allow such setting to avoid exposure of fluid to the permanent casing. Simulation supported that the ESP depth , for the cases in study, could be set at much lower depth before it exhibit any degradation in performance and deviation from performance curve. Gas volume fraction was less than the limit of 15% by some manufacturer of ESP's for the pump to exhibit degradation in performance. The pump setting depth of the case was low enough, ±2000’, that would result in saving in pipe, cable, and may prolong the operation of the pump due to operating at lower temperature. Comprehensive approach to calculate performance of ESP at different depths and consider operational aspects, were conducted. Operational considerations included well performance, integrity, and reservoir monitoring, well control. Special calculation were made to check the gas volume fraction in pump stage that will impact performance. The approach was good to have an answer of the setting depth. Subsequently, cost saving in pipe, cable could be realized. Thermal effect on flow and performance could be considered to improve calculations.