Application Of Hybrid ESP-Gas Lift In Multilayer Carbonate Reservoir Of Ujung Pangkah East Java Offshore Field

Abstract

Ujung Pangkah Offshore Field as the main oil & gas producing field of Pangkah PSC Block, has been produced from a total of 30-40 wells since 2007. The field has been using gas lift as its main artificial lift method considering the availability of gas rate to be injected and gas lift handling equipment capacity. However, the increase of more oil development wells & oil converted wells since 2019, all renders gas lift injection capacity considerably limited. Based on these constraints, in addition to the unused power
availability from gas turbine generator, ESP (Electrical Submersible Pump) is decided to be trialed starting in 2020.

X1 & X2 wells, formerly a gas-lift-enabled oil producing wells, are selected for ESP trial well candidates. These wells are both qualified to install and utilize ESP since these wells have relatively high productivity index and meet ESP artificial lift selection criteria. In addition to the usual ESP components (multistaged pump, motor, power cable, surface control equipment & Variable Speed Drive), gas lift valves inside gas lift mandrels are also installed above ESP system to enable contingent production with gas lift and to ensure the sustainability of well production rate when these ESP components experience trip/failure. To accommodate for ESP operation with pump maximum GOR limitation, these wells are also equipped with AGH (advance gas handler) and gas separator sub to remove free gas from produced fluid through annular venting valve. This annular venting valve & annular packer installations, as part of ESP completion, are one of the requirements to comply with company “well dual barrier policy”.

Application of X1 ESP-GL conversion is conducted in Q3 2020, while X2 is conducted in Q1 2022. Even though it is being trial tested, X1 ESP pump has been running for almost 2 years to this day. Production rate increases with gain more than 348% in comparison to its depleted rate prior to ESP-GL installation, and saving up to 1.2 MMscfd additional gas lift rate capacity. X2 ESP yields gain to 38% of its last rate pre-ESP-GL installation, saving 1.1 MMscfd gas lift rate capacity.

The conclusion is, the installation of hybrid ESP-GL system has been successfully applied in 2 wells in Ujung Pangkah field. For further strategy, another well is planned to be applied with the same hybrid ESP-GL system. Proper installation referring to fluid properties & production rate and proper operational procedure to maintain ESP pump run life is currently a key to maximize production opportunities particularly in limited offshore field.