Improving Well Performance with Bottom Feeder Intake on Electric Subsmersible Pump in Gassy Wells

Abstract

Oz is an offshore oil field with Electric Submersible Pump (ESP) as the main artificial lift system. Gassy well condition become a key challenge in this field as some ESP wells trip due to pump gas locking, and this is leading to production deferment and ESP failures. Several applications such as gas separator, gas handler, and multiphase pump have been installed on the ESP system, but gas locking is still occurring in some wells. This paper will present a new approach at Oz field to improve well performance by implementing bottom feeder intake application on electric submersible pumps in gassy well.
To analyze this gas locking problem, well production simulations were performed and found out that flow pattern below the ESP completion is slugging at some well conditions. As in slugging flow pattern the liquid hold up in the annulus may reduce to 30%, thus when the slug reach pump intake a large amount of gas volume will enter the pump and create gas locking. In this condition, gas separator or gas handler would not able to prevent gas locking to happen on the pump. Bottom Feeder Intake (BFI) was proposed as a solution in handling gas when slug flow pattern occur in ESP wells.
Electric submersible pump with bottom feeder intake were successfully installed in several wells in 2016. The bottom feeder intake was combined with gas separator and still operating since then. This application significantly minimizes gas locking problem, reduces deferred production, and gives opportunity to increase production of ESP wells.
Through well production simulation and analyzing the effect of fluid flow pattern below ESP completion to pump gas locking symptom, bottom feeder intake has been chosen as an effective solution minimize gas locking in gassy well.