Su Tu Nau field, also known as the Brown Lion field, is located in Block 15-1, Cuu Long Basin, Vietnam, approximately 180km south-west of Vung Tau, at a water depth of approximately 40m. Discovered in September 2005, the offshore field is estimated to hold 120 million barrels of oil reserves.
It is owned and operated by the Cuu Long Joint Operating Company (CLJOC), a joint venture (JV) of Petrovietnam Exploration Production Corporation (PVEP-50%), ConocoPhillips Vietnam (23.25%), KNOC (14.25%), SK Innovation G (9%) and Geopetrol (3.5%).
CLJOC also operates the Su Tu Den (Black Lion) Southwestern, Su Tu Vang (Gold Lion), Su Tu Den Northeast and Su Tu Trang (White Lion) fields at Block 15-1, which covers an area of approximately 800km².
The Su Tu Nau field produced its first oil in October 2014 and currently produces from seven wells at a rate of 37,000 barrels a day, which is expected to peak to 50,000 barrels of oil a day (bpd) in the near future.
Su Tu Nau field development and infrastructure details
The field development primarily involved the construction of two unmanned, four-pile wellhead platforms (WHPs) namely Su Tu Nau North (STN-N) and Su Tu Nau South (STN-S), which were fabricated at PTSC Mechanical & Construction’s (PTSC M&C) yard in Vung Tau.
Modifications were also performed on the existing WHP-A, WHP-B and the Su Tu Vang central processing platform (CPP), which also processes the oil from the Su Tu Nau field.
Approximately 60km of seven subsea pipelines and 24 subsea spools were laid to connect the field to the Su Tu Vang CPP. It comprised three production pipelines, two gas lift pipelines and two water injection pipelines.
The WHP jackets installation was completed in October 2013, while the topsides, pipelines and subsea facilities were installed by October 2014. Early drilling activities at the field started in the last quarter of 2013.
Each of the two WHP jackets weighs more than 1,000t and further integrates 2,500t of piles. The topsides of STN-S weigh 2,042t, while those of STN-N weigh 1,837t.
The Su Tu Nau facilities are designed to produce 50bopd and 50,000 barrels of total liquid a day.
Contractors involved with the Cuu Long Basin field
The letter of intent (LOI) for the supply of the WHP jackets was awarded to PTSC M&C in March 2013. The company was further awarded the engineering, procurement, construction, installation and commissioning (EPCIC) contract for the topsides, pipeline and modifications to the existing platforms in November 2013.
Swiber Offshore Construction (SOC) was subcontracted by PTSC M&C to perform transportation and installation works. Detailed design of the WHPs was performed by PetroVietnam Engineering.
The manifolds valves, ball valves, double block and bleed valves, and monoflanges for the WHPs were supplied by Sami Instruments. EEW Group supplied structural steel pipes for the WHPs.
PetroVietnam Coating provided pipeline and bend coating services for the project, while specialised coatings for the project’s pipe components were performed by OAG Group. Welding works for the pipelines were performed by Serimex.
Kreuz Subsea was involved in the installation of the field’s subsea infrastructure. Non-destructive testing services for the field’s infrastructure were rendered by Alpha NDT.
Engineering and fabrication of the field’s pump skids were performed by DK Engineering, and air compressors and dryers were supplied by Airpack.