Platong II Gas Project, Thailand

The Platong II gas development is a natural gas expansion project of the existing Platong complex in the Gulf of Thailand. Scheduled for completion in 2012, the proposed development will involve the installation of a new gas receiving, processing and export platform and a new living-quarters platform.

The project is expected to double natural gas production from the 10, 10A, 11 and 11A concession blocks in the Greater Platong area. It will involve an investment of $3.1bn.

System de-bottlenecking and brownfield partnerships on the existing Platong complex will also be carried out as part of the project.

As of April 2010 the project was 49% complete.

The project is operated by Chevron, which owns 68% of the project with the remaining is held by Mitsui Oil Exploration (27.4%) and PTT Exploration and Production (2.8%).

Platong II platforms

The new platforms for Platong II will be installed 120m offshore Thailand, adjacent to the existing Platong complex in shallow waters of 70m depth. Both platforms will be linked to the existing facilities via a bridge.

The gas processing platform will consist of two gas processing trains fully equipped with compression, dehydration, dew point control, mercury removal, condensate stabilisation and water-handling facilities.

The facilities will operate at a nameplate capacity of 420 million standard cubic feet per day of sales gas, 22,000bpd of condensate and up to 60,000bpd of produced water. Approximately 30 remote wellhead platforms will be installed over the lifetime of the development.

The topside structures will be installed using the float-over technique, a method used by Chevron for the first time in the Gulf of Thailand. Installation weight of the gas processing platform topsides is estimated to be 18,500t. Using the float-over technique, the entire topsides unit will be loaded onto a barge taken to the installation site and floated over the installed jacket structure.

The living-quarters platform will be either a separate facility installed over a fixed steel jacket southeast to the current living quarters or will be integrated with the central gas processing platform on the same steel jacket structure. Designed similar to the existing living quarters platform, the new living-quarters will accommodate 200 beds.

Subsea systems

To provide gas and condensate to the new facilities, three new subsea trunk lines will be laid as part of the project.

The 115km intra-field pipelines will carry the three-phase reservoir liquids from the wellhead platforms to the central processing gas platform.

Gas processed, conditioned and compressed at the platform will be exported through a new 24in sales gas pipeline, which will be connected to the central gas processing platform via a 45km export trunkline. A condensate / oil pipeline will be laid connecting the central processing gas platform with the pre-installed PLFSO Pattani Spirit.

Platong II output

The Platong II development will produce natural gas, increasing the country's gas processing capacity by 420 million cubic feet. The added capacity will account for 14% of natural gas consumed for power generation in Asia Pacific.

The project will be a major contributor in increasing Chevron's daily contract production of natural gas to 1.2 billion by 2012. In an agreement with the Ministry of Energy of Thailand, Chevron agreed to boost its natural gas production by 500 million from ioffshore blocks 10, 11, 12 and 13.

Contractors for Platong II

The engineering, procurement, construction and installation (EPCI) contract for the project was awarded to the subsidiaries of J Ray McDermott.

The contract includes the entire EPCI scope associated with the gas processing platform, the living-quarters platform, flare tripod and three bridges.

The conceptual design engineering contract was awarded to WorleyParsons. The contract included the company's Select phase conceptual design engineering services for the new facilities, front-end engineering and design, and procurement services including the acquisition of long -ead items.