Designing a simplified approach to upgrading a subsea control system.
The Challenge
The client operates a vast gas production network of over 60 wells. They were experiencing an unacceptable number of spurious shutdown trips and also required an upgrade to their existing subsea control system to support an eight well expansion development project.
Our Approach
Advisian worked with the client to design a simplified approach to the subsea control system upgrade. The team attended a 'cause and effects' hazard and operability study (HAZOP) workshop to review the existing subsea controlled shutdowns. The team:
- Identified subsea controlled shutdowns that were causing spurious trips (loss of hydraulics), that were not credible and could be removed
- Updated all required input drawings and documentation (with cause and effects matrices and philosophies)
- Worked with the subsea control vendor to ensure the subsea control system upgrade deliverables complied with the design intent
- Supported the client with the subsea control system upgrade performed offshore
Results
Advisian assisted the client with the upgrade offshore, which meant a seamless changeover (zero production downtime during the upgrade). Our approach achieved:
- A reduction from six spurious shutdowns per year to zero occurrences post control system upgrade
- Production control system availability achieving more than 99%
- A simplified shutdown process