Transition from Gas Lift to Electric Submersible Pump in Wells with High Gas Volume Fraction - Avenues for Profitability in Challenging Markets - A Novel Case Study of an Indian Offshore Field

Abstract

Abstract 27 gas lift wells of an Indian Offshore field were studied for feasibility of conversion of Gas lift mode to ESP. The wells have good productivity indices ranging from 1 barrel /day/psi to 6.9 barrel /day /psi. However, the production challenge was to operate these wells in a region where bubble point pressure was higher than the formation pressure itself and thus posed problem of gas evolution at the wellbore. During ESP operation in High Gas Volume Fraction (GVF) regions, extreme difference in the densities of the liquid and gas lead to a low pressure area in the Impeller during the pumping operation across the stages of ESP, resulting in gas accumulation. Free gas in these stages displaces liquid and lowers down the volumetric efficiency of the pump. In the past, 13 offshore wells were installed with ESP and many of these ESPs failed. Their failure analysis was used as a guiding light for designing successful ESP solution for other 27 candidate wells of the same Offshore field. Different methods & practices for handling gassy wells were studied and their application was analyzed. This study was aimed at finding solutions to mitigate the effect of gas interference in ESP while enhancing the production from the wells. Moreover, the paper also draws a strategy for future ESP pilot projects in high GVF fields.