Perpustakaan Digital ITB

Artificial lift helps to increase the flow of well fluids to the surface or to a facility by adding pressure or extra energy, which is required when the reservoir pressure is insufficient to lift the liquid to the surface or facility. Besides, artificial lift is frequently used to increase the flow rate in naturally flowing wells. The electrical submersible pump (ESP), is a widely-used and reliable artificial-lift method for lifting high volumes of fluids from wellbores. ESP is easy to install and operate, but it has some limitations such as high-voltage electricity availability, non-applicable to multiple completions, unsuitable for deep and high-temperature oil reservoirs, troublesome gas and solids production, and costly installation and repair. Due to its pump capability not being suitable for reservoir performance, the ESP may become inefficient enough to lift the oil over time. As a result, as the reservoir pressure drops, the reservoir's performance declines, and the reservoir no longer has the support it once did to flow. A case study in this research is carried out on observing Well X. The main objectives of this study are to find the underlying cause of the production decline and to optimize the ESP performance by considering which parameters should be redesigned. In the redesign of the ESP, the new optimum rate obtained from the absolute open flow IPR is used. From the optimum rate, it can be seen whether the ESP being used is optimal or not. Observation of the plot from diagnosis results in declining production, the decline of well productivity was caused by the occurrence of multiphase flow, indicated by a sudden high increase in gas production. From calculating the IPR, it is obtained that the optimum rate does not match the production range of the ESP that is being used, so the ESP needs to be redesigned. The ESP design resulting in a recommendation to replace the pump from the previously used QN-55 130 series to QN-70 130 series and replace the motor from 225 HP/2220 V/58 A to 64.3 hp/ 1342 V/ 35.1 A.