Ca Tam oil field is located in Block 09-3/12 offshore Vietnam in 15m-60m of water depth. Credit: VIETSOVPETRO.
Construction of the CTC1 wellhead platform was started in March 2018. Credit: Vietnam Oil and Gas Group.
First oil from the field was achieved in January 2019. Credit: Vietnam Oil and Gas Group.

The Ca Tam oil field, also known as Sturgeon, is located 160km south-east of Vung Tau City, offshore Vietnam.

The field is being developed by a consortium comprising Vietsovpetro (55%), a joint venture between Vietnam Oil & Gas Group (PetroVietnam) and Zarubezhneft, PetroVietnam Exploration Production (PVEP, 30%) and Bitexco Group (15%).

The consortium signed a production sharing contract with PetroVietnam in September 2012. Vietsovpetro is the general contractor and operator of the filed.

First oil from the field was produced at a rate of 1,630t per day in January 2019. The oilfield is expected to remain in commercial production until 2032 and will generate significant revenues for the project partners and state government.

Ca Tam oil field location and discovery

The Ca Tam field is located in Block 09-3/12 of the Cuu Long basin. The block covers an area of approximately 6,000km², with water depths ranging from 15m to 60m. It lies near production fields including Rong, Gau Trang and Bach Ho, which are operated by Vietsovpetro.

Ca Tam was discovered by the 2-X exploration well drilled in 2014.

Ca Tam oil field exploration and appraisal

Commercial volumes of oil were confirmed in the Ca Tam oilfield with the drilling of the CT-3X exploration well in October 2015. The first Upper Oligocene zone of the well was production tested and flowed at a rate of 1,300m³/day, while the flow rate in the second Lower Miocene zone was 550m³/day.

A second exploration well named CT-4X was drilled and encountered productive sediments at a greater depth compared to the exploration well CT-3X. It flowed at a rate of 650m³/day during the production test.

Development and infrastructure details

Development plans for the Ca Tam oilfield were approved in July 2017. They include the installation of two wellhead platforms (WHP), CTC1 and CTC2. The CTC1 platform was installed in phase one, while the CTC2 platform will be installed at a later date.

The platform has a 1,100t superstructure and topside with a vent boom, along with a jacket with boat landing. The topside accommodates gas lift, water injection and several other utility systems. The platform also includes 12 well slots, module support frame in the sub-main deck, and a helideck.

The CTC1 WHP is connected to Vietsovpetro’s existing platforms at the White Tiger, White Bear and Dragon oilfields located in Block 09-1 through subsea cables and pipelines.

Initial flow from three tie-back wells was 11,900 barrels of oil per day (bopd). The field is expected to produce oil from seven continuous wells in 2019 with an average output of 16,000bopd, which is expected to peak to 23,000bopd in 2020.

Processing details

Well stream fluid is processed on the topside facilities of the CTC1 platform. Liquids produced from the CTC1 platform are further processed at the RP2 platform at Dragon oilfield.

The separated gas is transported to the central compressor platform at White Tiger oilfield via the BK14 and GTC1 wellhead satellite platforms. The GTC1 platform supplies gaslift and water injection to CTC1 through subsea pipelines.

The RP2, BK14 and GTC1 platforms were modified to receive and process oil and gas from the field.

Contractors involved

Petroleum Equipment Assembly & Metal Structure was responsible for the construction and installation of the CTC1 wellhead platform.

LILAMA 18 built foundation piles and berths, while construction was performed by ALPHA ECC.

Vietsovpetro’s Offshore Construction Division provided construction and installation services for the platform, while Vietsovpetro Science Research & Engineering Institute provided design and engineering services.

CNI was contracted to supply oil heater skids, pressure tanks, a glycol heater and a heat exchanger for the platform, while Vietnam Petroleum Institute supplied 85t of Al-Zn-In alloy sacrificial anodes for the platform jacket.

Cyclotech provided seamless pipe, beam and angle bar for the platform, while anti-corrosion materials were supplied by CTAT – Vietnam Petroleum Institute.

PetroVietnam Coating supplied insulation coating (3LPE) and concrete weight coating services for the gas and gas lift pipelines.

Green Star Positioning provided positioning and navigation services for the movement of the Swiber Concorde barge carrying the CTC1 Jacket.