Offshore Dehydration: Shell (SSB) B-11, Malaysia
The B11 platform, offshore Malaysia, was the first commercial application of the Twister supersonic gas technology following six years of research and development.
The goal was to provide a safe gas processing solution with minimal environmental impact, while providing a significant reduction in capital and operational expenditure. 12 Twister units and 2 Hydrate Separators were provided with Twister and Shell Sarawak agreeing on a three-year Process Operation & Availability Guarantee (POAG).
The risks associated with TEG sour gas dehydration (20% CO2 & 3500 ppmv H2S), economics and flow assurance made the operator decide to select the Twister Dehydration option. Criteria included.
- The fact that it was a closed system (no H2S emissions) with a minimum inventory was very important to the operator
- Operations & low personnel requirements. Operations were normally unattended
- The Twister technology provided the lowest CAPEX and life cycle costs as well as a 25% topside weight saving
- No glycol regeneration and its associated operations would be required.
- A guaranteed uptime of 98%
- Flow assurance. The protection of a 65 km CS pipeline (no free water)
At start-up in Dec 2003, the B-11 Production Platform was the first offshore dehydration facility producing pipeline spec gas without glycol inhibition. During the first three years operation and the years thereafter, the Twister Trains have proven availability of >99% and production of gas to pipeline specification warranting dry gas export to E-11 platform (14 °C WDP for 2-phase export stream).
After 10 years of operation, the Twister technology has delivered significant accrued value as compared to a traditional glycol-based chemical solution. These include:
- High availability and flow throughput. With more than 10 years on-stream, no shutdowns and >99% availability. Minimal retention time with no internal hydrate formation and glycol inhibition and only half an hour start up compared to nine hours for glycol-based systems.
- Improved base case economics. With weight savings of 25% compared to alternative platforms and estimated CAPEX savings of 23%.
- Flexibility. The ability to handle varying feed gas compositions and multiple wells.
- Safe and simple operations. For H2S dehydration due to a closed loop system with no emissions, minimal interventions and no Twister-related HSE incidents reported. No glycol regeneration, no tail gas and no toxic emissions.
- No maintenance Issues. Static equipment with minimal wear and tear and no glycol plants.
- Flow assurance. No pipeline integrity issues reported and water dry exports secured by closely monitoring water content in gas and condensate.