PLANT LOCATION: Sarawak F23, Malaysia


Plant description

Sarawak F23 offshore gas hub exports gas to LNG plant in Bintulu Sarawak.
The processing facilities on F23 complex consist of one compression train, composed by a GE LM-2500 aero-derivative gas turbine and an Elliot 23MB3/2 centrifugal compressor, that receive natural gas from three different wellheads:

  • F23 (approximately 200 MMstdft3/day » 235974 stdm3/h)
  • F29 (approximately 100 MMstdft3/day » 117987 stdm3/h)
  • Cili Padi (approximately 200 MMstdft3/day » 235974 stdm3/h)

The control system is based on Woodward Micronet and Bently Nevada 3500.
Due to a variation of the gas composition, the compressor O&M (Ebara) produced a different set of compressor maps valid for the new gas conditions.
The Customer’s request was to improve the reliability and availability of compressor stations in order to be able to manage the wellheads selection .

It was requested to upgrade the control system configuration based on the new compressor maps and to supervise on site in order to organize and execute the necessary validation tests. Since it wasn’t available, the original control system specification had to be evaluated by reverse engineering studies.




SSE has defined the new parameters of the ASV control system, based on the new compressor map provided by EBARA. Before starting the site activity, SSE provided an Anti-surge Work-Sheet, that summarizes the compressor relevant parameters and all information necessary to be implemented in the control system, and a dedicated test specification, defining the main specialists to be involved in the test activity.
The site activities can be summarized as following:

  • Gas parameters and surge curve upgrading on control system
  • Surge test and new surge curves validation. During the test, the Process gas

flow is maneged in order to bring the operative point upon the theoretical surge curve and verify that no surge phenomena occurs. The surge criteria is based on the harmonic and sub-harmonic contributions of the radial vibration measurements.

  • Anti-surge controller tuning
  • Anti-surge controller reaction testing in case of wellhead selection change.

Managing the wellhead’s suction valves, closing one or more sources, the stable behaviour of compressors has been verified.




SUPPLY Anti-surge Configuration Worksheet
Site Anti-surge Test Procedure
Site Activity
CONTROLLER Woodward MicroNet


Type  of Project:

Parameters upgrade into an Integrated control system for the gas turbine and compression trains. The new control system shall guarantee a very reliable and stable turbo compressor operation.

Scope of supply:

Engineering activity in order to optimize the control system based on new compressors maps provided by O&M. Site activity coordination for Anti-surge tuning and testing for the turbo compressor train.



Higher plant “availability” thanks to reduced unplanned halts, reduced downtime for troubleshooting. Optimized plant performance resulting from prompt and accurate monitoring and control of functional parameters