Abstract
Abstract
Selection of the most suitable production technologies; namely the type of lift to be used, to the design and implementation for well conditions has been one main responsibility of petroleum engineers. In an especially limited offshore field, not all methods are applicable as platform spaces, operating costs, and system reliability are needed to be considered. System reliability, for instance, entails well production profile to meet the acceptable operating range and to perform within specific run life to be rendered economic.
Ujung Pangkah offshore field, located within Pangkah PSC Block off the northeastern coast of Java Island has been discovered in 1998 and carries on production since 2007. Having a typical gas cap with an oil rim, carbonate reservoir; Ujung Pangkah field has since been developed with commingle completion targeting both separated layers of oil zone and gas zone, utilizing only gas lift as its main artificial lift method. Concern for alternative lifting methods has arisen since 2019, due to the limitation of gas lift injection capacity that is no longer adequate for the current and future development wells at that time. Considering this challenge, Saka Energi Indonesia decided to perform ESP (Electrical Submersible Pump) trial on 2 wells.
By design, the proposed completion will be of a hybrid ESP-Gas Lift, possessing both ESP components and typical gas lift components. ESP is decided to be the next artificial lift method to be applied because currently there are unused electric capacities from Gas Turbine Generators. To satisfy the acceptable range of ESP design criteria, both wells are equipped with AGH (Advanced Gas Handler)/Gas Separator, along with a gas vent line to produce this separated gas through the annulus. To fulfill the required dual-barrier-policy in offshore conditions, these wells are using specialized, feed-through-ESP hydraulic packer that enables ESP cable and gas vent line to be passed through. To ensure these wells reach the economic limit of ESP installation, this hybrid completion design is used; utilizing ESP as the main artificial lift and gas lift as a backup so that the well can still be produced with gas lift when ESP experiences failure.
On the implementation side, the installation of ESP with backup gas lift on 2 wells has been successfully improving production, each up to 4.5 times and 1.5 times its previous oil rate pre-installation. Despite the first ESP being out of commission, ESP run life has been satisfied and the relative economic limit for the installation has been reached. In addition, the well can still be flowed with a backup gas lift system while waiting for pulling operation, which significantly extends the well run life and overall boosts the well's economic value.