The North Rankin Complex (NRC) is one of the largest offshore gas and condensate processing facilities in Australia.
It is a single integrated facility consisting of two interconnected production platforms- North Rankin A (NRA) and North Rankin B (NRB).
Associated subsea infrastructure includes two export trunklines- 1TL and 2TL, which connect the NRC complex with the onshore Karratha Gas Plant (KGP).
The facility, located off the coast of Western Australia, is operated by Woodside Energy on behalf of the North West Shelf Project participants.
Besides Woodside Energy, the project’s other participants include Japan Australia LNG (MIMI), BP Developments Australia, Chevron Australia, Shell Development (Australia), and BHP Billiton Petroleum (North West Shelf).
NRA commenced operations in 1984, while NRB became onstream in 2013.
The manned NRC facility is capable of exporting up to 66 kilotonnes (kT) per day of gas and 6kT of condensate per day.
Woodside submitted an Environmental Plan (EP) for NRC, which was accepted by the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) in August 2014.
A revised EP was accepted by NOPSEMA in April 2017.
North Rankin Complex Location Details
The North Rankin Complex is situated offshore around 135km from Dampier on Western Australia’s northwest coast.
Water depth at the site is about 125m.
Both platforms, NRA and NRB, are located within the Production Licence WA-1-L, while the trunklines lie in Pipeline Licences WA-1-PL, WA-10-PL, TPL/15, and TPL/16.
The Goodwyn gas field lies around 23km south-west of the North Rankin A platform.
North Rankin Complex Details
As the central facility to Woodside’s NWS Facilities, the North Rankin Complex is connected to GWA platform by a 23km and 30-inch Inter-Field Pipeline (IFL) and Karratha Gas Plant by two 130km, 40-inch (1TL), and 42-inch (2TL) export trunklines.
The NRC is also connected to the Angel Platform via a 50km 30-inch pipeline and power umbilical, and Okha Platform by a 33km and 12-inch export pipeline.
The NRC produces dry gas and condensate from the North Rankin, Perseus and Persephone fields. After processing, the gas and condensate are transported via 1TL and 2TL export trunklines to the onshore Karratha Gas Plant.
The other facilities are connected to NRC via subsea tie-in assemblies to the first and second trunklines to enable hydrocarbon export to the Karratha Gas Plant.
NRA features an eight-legged steel pile jacket along with a piled and guyed steel tripod flare support structure.
It has six main levels with the production deck situated at an elevation of 23m above sea level. The accommodation modules are located at the southern end of the platform, separated from the hydrocarbon processing equipment and flare systems.
The product export pipeline riser is near the centre of the platform.
Overall, NRA platform includes 23 topside modules.
The NRB platform, featuring a four-legged piled steel jacket with an integrated float over deck, lies approximately 100m west of the NRA jacket.
NRB conducts gas compression and condensate pumping of output produced from the NRA wells.
The two platforms are connected by two bridges. One is for pedestrian use, while the other is for supporting all the interconnections and provisions for maintenance and material traffic.
According to the EP of 2017, the project had 29 platform-based wells in production.
The NRC is usually manned, but it can be remotely operated during extreme weather conditions.
Key Contractors Involved
Over a 27-month period, Safehouse Habitats (Scotland) delivered multiple habitats to NRA to enable construction and hot work to take place with minimal impact on production. This included the delivery of SafeCool, a portable air conditioner.
A long-term major services agreement was signed by Woodside and Vertech Group in 2022. The work scope included specialist maintenance, brownfields, engineering, turnaround excellence, and projects. The other works included pipelines, subsea, and decommissioning services.
FoundOcean won the grouting contract for the North Rankin B platform installation via Heerema Marine Contractors.
CSIRO Division of Geomechanics assisted in understanding the behaviour of sub-seafloor carbonate sediments and helped in addressing the foundation problems faced during the installation of steel piles to the sea floor.
