Abstract
The Greater Bongkot North (GBN)'s condensate stabilization system initially utilizes multi-stage flashing concept through the multi-stage separators. Most of the flashing gas at the last stage separator could not be recovered as being operated at very low pressure (0.05 barg) resulting in the continuous flaring through Low Pressure (LP) Flare Header at the Production Platform of the GBN since 1st operation day. Recovery of the unrecoverable low-pressure gas has been unsolved since then.
Regarding lower gas nomination forecasted and exported condensate rate in low condensate production mode, LP flare rate is being simulated at 1-3 MMSCFD whilst the existing condensate and gas recovery system shows the available capacity left over even the field potential is maintained. This information energized the opportunity of Recovery Scheme by boosting the pressure of LP Flare Gas and feeding the recovered gas to the existing FGRU compressor within the minimal modification scope. Entire feasible recovery options had been technically examined including essential requirements of modification to evaluate the Pros and Cons on each development scenarios.
Key engineering challenge on recovery of the low-pressure heavy flare gas is the closed recirculation of recovered hydrocarbon which wastefully occupies the system capacity. Selection on the returning point of the recovered gas is crucial to minimize the recirculation while increasing production yield. The selected option provides less modification works whereas the entire recovered gas feeding back to the existing FGRU compressor is feasible while the existing facilities at its maximum capacity are utilized and new equipment installation requires only one (Wet Screw) compressor and one liquid recovery (Vertical in-line centrifugal) pump. Each equipment was technically selected through evaluated technical specifications and limitation of installation spaces. Furthermore, the installation scenarios on the aging production platform are key challenge as deck extension, which new equipment are installed, is heavy-lifted, and installed on the existing lower deck of Production Platform using the available margin of platform load on the existing piles. Cost estimation is conducted together with economic evaluation for investment decision. The project is budgetary approved providing an attractive positive NPV. The economic evaluation results in positive NPV mainly due to the condensate gain from the flare gas recovery insisting that greenhouse gas reduction project could be performed in the techno-economical way.
The implementation of GBN New LP Flare Recovery scheme will soonest be getting started by FEED and Construction phases accordingly to shape up essential details of required engineering aspects to make the start-up of this project meets the timeline supporting Sustainable Development framework (Green-house gas reduction) as PTTEP strategic directions.
