Geosyntec prepared the quantitative risk assessment (QRA) for the Browse liquified natural gas (LNG) offshore central processing facility (CPF) during the front-end engineering design (FEED) stage of this multi-billion dollar project.
Geosyntec Scope of Services:
The Browse LNG project is an LNG export facility being developed off Australia’s northwest coast. The facility will distribute gas from three gas fields, estimated to have reserves of 13.3 trillion cubic feet of dry gas and 363 million barrels of condensate, capable of supplying Australia’s current gas needs for 40 to 50 years. The project includes an onshore three-train LNG facility, 1200km of subsea pipeline, a CPF, and three dry tree unit (DTU) tension leg platforms. The CPF will be located in shallow water on the Australian North West Shelf. The facility will receive well fluids from three infield deepwater production facilities, process the received gas and condensates, export the processed hydrocarbons to a Greenfield LNG plant located at James Price Point on the Dampier Peninsula, north of Broome, Western Australia. An Excel-based linked spreadsheet model, containing all the elements of a QRA and supported by visual basic for application (VBA) code, was developed for this project. This was to satisfy the clients key requirements, which were to develop a QRA model that: Supported a comprehensive assessment of the risks on the CFP platform to support the demonstration that the risks are both tolerable and are low as reasonably practicable (ALARP) and has sufficient detail to support the project’s evolution through detailed design and into the operational phase.
This QRA determined the risks for a number of manning scenarios for three different operational phases of the installation, which took account of additional tie-backs and processing facilities for both hydrocarbon and non-hydrocarbon hazards. The assessment also determined the risks to personnel undertaking operations and maintenance visits to the DTUs. The model was developed to determine the risk measures as defined by the client: potential loss of life; area specific individual risk per annum; individual risk per annum; temporary refuge impairment frequency; and the bridge impairment frequency. The advantages of this model, which was handed over to Fluor and Woodside Engineering Limited (WEL), are that it is easy to use, transparent, and allows the rapid assessment of any changes. In addition to preparing the QRA model for the CPF, Geosyntec also undertook peer reviews of the QRAs developed in parallel by MODEC and Aker Solutions for the DTUs during front-end engineering design (FEED).