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Wheatstone Upstream Project Subsea

Wheatstone Upstream Project Subsea 
23
production wells
Yes
Yes
Yes
Yes
No
Office: Australia 
Customer: Chevron Australia Pty Ltd 
Location: Perth, Australia 
Timeframe: 2008 - 2015 
INTECSEA was responsible for the subsea facilities design and equipment, including wellheads, trees, tie-in spools, manifolds, pipeline tie-in structures, subsea control system, subsea umbilicals and distribution; production flowlines, PLETs, in-line tees and subsea isolation valves; and the export trunkline system including the pipeline, subsea isolation valves and shore crossing.


Project Highlights
The Wheatstone gas to LNG project incorporates two fields: Wheatstone and Iago, located in the Northern Carnarvon Basin of offshore Western Australia. The project will produce from exploration permits WA-253-P, WA-17-R and WA-16-R, located roughly 90 mi (145 km) offshore, approximately 62 mi (100 km) north of Barrow Island and 140 mi (225 km) north of Onslow, respectively. The system design consists of a subsea tieback to a production platform with a single export line to an LNG facility onshore. Three production flowlines will tie six drill centers comprised of 23 production wells back to the platform.


Project Configuration

  • Wheatstone has four manifolds with 20 well capacity (15 prod & 5 spare) and Iago has two manifolds with 12 well capacity (8 prod & 4 spare)
  • Production flowlines (3), utility lines (2) and MEG (2) supply lines connect to the Wheatstone production platform
  • A single export trunkline transports gas 220 km to an onshore LNG facility
  • A 14-in Utility line provides start-up and operational flexibility
  • A 6-in MEG line assists with hydrate mitigation at start-up and shutdown
  • A single 44-in export trunkline provides feedstock gas for the LNG facility
  • Subsea Trees are 7-in large bore Vertical Trees; Manifolds are either 6-slot or 4-slot designs


Customer Challenges

  • Flow Assurance: hydrate mitigation – adopted an insulate and blowdown plan
  • Flow Assurance: at well start-up, temperatures could drop to -65 deg C
  • Erosion: maintaining production rates with the least number of wells – well flow rates needed to be at least 250 MMscfd 
  • Reliability/Availability: Subsea system (completions, trees, manifolds, controls, flowlines and umbilicals) must be equal to or greater than 99.33% over 30 years


Project Services
INTECSEA performed pre-FEED engineering (concept selection) in 2008, performed transition engineering work (additional concepting) betwee June-December 2009, performed FEED engineering from January 2010 through March 2011 and performed post-FEED engineering from April 2011 through July 2011. INTECSEA is currently providing detailed engineering oversight.


Results
INTECSEA successfully completed all select and definition phases and continued to support Chevron by assisting with the execution phase.

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