Apache North Sea Limited TB5400 Controls Upgrades

Problem

Apache North Sea Limited operates two TB5400 Gas Turbines on its Forties Charlie asset (First production 1975).

The units (K01, K02) are employed in a mechanical drive (Gas Compression) application, and since their original installation in the 1970’s have been progressively updated to the new TB5400’s installed in the past few years.

The associated engine control systems were also progressively updated from the original Ruston controls to HSDE “Digicon” in the 1990’s controlling TD4000/TB5000’s, to HPI’s PLC based “Digicon Replacement Units” controlling TB5000’s in 2006. These controls were further upgraded in 2017-19 to accommodate the TB5400 engines.

In addition to implementing the revised control algorithms each engine upgrade required, the opportunity was taken to update the control package to overcome obsolescence issues, comply with Apache’s HSE policies, and improve overall package reliability and supportability.

The Forties field was earlier envisaged to be decommissioned in 2013 but the life of the field has been extended by an additional 20 years.

The HPI Energy Services Solution

Due to a sound legacy of success within the North Sea region and its familiarity supporting the HSDE “Digicon” controllers, HPI Energy Services Limited (HPI) was approached to offer its upgrade solution.

HPI was extensively involved throughout the package upgrade project which comprised upgrading the engines, compressors and associated ancillary systems in addition to the control systems. HPI was an active team member during the FEED, HAZID/HAZOP/SIL analysis and planning phases prior to the project kick-off.

Key features of the control system design:

• Critical Signals up to SIL2 depending on the
outcome of the SIL analysis.
• Instrumentation upgraded to EXd in accordance
with Apache policy
• Integrated vibration monitoring (BN 3500)
• Enhanced local and remote HMI
• Enhance communications with Platform DCS (Delta IV)
• Remote I/O to reduce cabling
• “Pre-fabricated” design to enable mounting of the control equipment into the existing 19” panels thus minimising control room disruption.
• Dual Fuel (gas or liquid) or Mixed Fuel (gas and liquid) operation.
• Integrated Compressor anti-surge control
• Updated “As-Build” documentation

Key Benefits

• Greater compliance with HSE expectations
• Increased package availability.
• Greater visibility of package performance, reliability and functionality (offshore & onshore)
• Enhanced troubleshooting capabilities
• Fit for field life extension.
• Similar upgrades to be rolled out across
• Apache’s Siemens Fleet, providing a common design solution