Gas Liquids Engineering Ltd. (GLE) provided engineering, procurement, construction support, and startup assistance for the install of six (6) DexPro™ dehydration units at Chevron’s flagship Gorgon Facility on Barrow Island, Western Australia. The Gorgon facility processes 2.6 BCF/d and 200,000 bbl/d of condensate.
Barrow Island is a designated A-class nature reserve for the purpose of conservation of flora and fauna. The marine environment around Barrow Island is also part of the Montebello-Borrow Island marine conservation reserves, which comprises of a wide variety of habitats and extremely high marine bio-diversity.
The Gorgon facility is configured with three (3) Acid Gas Removal Units (ARGU’s) each with a dedicated CO2 Injection Unit comprising of two (2) 50% CO2 compressors. The acid gas discharge from the CO2 compression trains is commingled and routed via a common header along the main pipe rack to the 7 km CO2 pipeline to the injection wells at 3 drill centres to the Northwest of the facility.
During preparations for the initial start-up it was determined that there were vulnerabilities within the CO2 system to off-design conditions which pose a risk of water condensation with associated rapid corrosion risk within the CO2 injection system’s carbon steel pipeline and piping.
To enable start-up of the CO2 injection system with minimal deviation from the intended startup dates and without risking the integrity of the carbon steel system it was determined that it was needed to reduce the water dewpoint of the CO2 being fed forward from the Gorgon facility compression system by the introduction of a recycle line to route CO2 from the outlet of the 4th Stage Discharge Cooler to the outlet of the 2nd – 3rd Stage Intercooler. The Joule Thompson (JT) cooling across the Temperature Control Valve (TCV) in the recycle cooling line will reduce the bulk temperature of the fluid, hence increasing water removal in the 3rd Stage KO Drum. This process is known as the DexPro™ process, which is a patented process developed by GLE.
The DexPro™ units will allow the facility to transition from venting CO2 to injecting CO2. The DexPro™ dehydration units have the following specifications:
- Six (6) 46 MMSCF/d Inlet Design Capacity
- Operation Commencing December 2018