The Cassia hub connects to the Mahogany-to-Beachfield pipeline via a 20-in. spur.

Cannonball, BP Trinidad and Tobago’s (bpTT) first normally unmanned installation (NUI) offshore Trinidad, was a multibillion-dollar milestone project that set the stage in terms of innovation, progressive thinking and developing local capability. The platform was completed in 2005 and reached first production in March of 2006 at a rate of 800 MMcf/d from three development wells. The NUI has a maximum capacity of 1 Bcf/d of gas and is tied back to the Cassia B central processing unit by a 26-in. multiphase pipeline.

With Cannonball, bpTT introduced the hub-and-spoke field development concept to the region. As the first platform for which the topsides and jacket were fully fabricated in country, the Cannonball platform was a milestone for the company and the country in another way as well. The project established the foundation for designing and fabricating future new field developments via standardized NUIs. The country now has a local fabrication yard and an in-country engineering office which was able to deliver two additional platforms less than two years after Cannonball.

Building on success

BPTT set the stage for local involvement with Cannonball. The full engineering contract was assigned to a joint venture company of Fluor Daniel with local partners Summit Engineering and Lee Young & Partners. The process of design engineering began in Houston in May 2003, with engineers from Trinidad and Tobago being mentored by engineers at Fluor. In December 2003, the Fluor Summit engineering team moved to Trinidad. According to bpTT, this is the first time that detailed design engineering had been done with Trinidad nationals fully incorporated in the team. The project included design and construction of the platform, the pipeline, hookup to the Cassia B offshore processing unit, and modifications to the Beachfield receiving facility, as well as upgrades to the separation and metering facilities.

In 2006, bpTT used the technology applied in constructing Cannonball and the experience gained by local companies to the planning and construction of the Mango and Cashima platforms, which were built in parallel that year achieving 25% local content in the design and fabrication of both platforms.

The concurrent construction program resulted in significant costs savings because bpTT was able to offer two projects to platform installation and pipe-laying contractors, which eliminated having to pay two separate mobilization fees. The company estimates that managing the projects concurrently saved about US $11 million on the designs for Cashima and Mango.

Launching Mango

In November, 2007, bpTT announced the start of gas production from the Mango field 35 miles (56 km) offshore Trinidad in the South East Galeota block in 235 ft (72 m) of water.

The Mango new field development project is the first phase in the development of the Red Mango field hydrocarbon resources, discovered in 2000 off Trinidad’s southeast coast. The Mango platform is built to the standardized design of Cannonball.

Facilities are based on the Cannonball “clone” design and were built on the hub-and-spoke development concept. The facilities consist of a nine-slot well protector platform and 26-in. offshore pipeline tied back to the Cassia B hub via the Cannonball field. When the field is fully operational, it is expected to add an incremental 1 bcf/d of gas deliverability along with some associated condensate.

“Mango will assist bpTT with its goal of safely and reliably producing 500,000 barrels of oil equivalent a day. It should be viewed as a reflection of bpTT’s strong commitment to developing local content in the petroleum industry,” said bpTT Chairman and Chief Executive Officer Robert Riley.

The 950-ton Mango jacket and the 980-ton topsides were built at the Trinidad Offshore Fabricators (Tofco) yard in La Brea, south Trinidad. Tofco is a joint venture between Chet Morrison Contractors of the United States and Trinidadian company Weldfab. The project included considerable Trinidadian local content, with 25% of engineering, procurement and construction value being spent in country. Trinidad and Tobago nationals were responsible for 65% of the project management hours and 85% of total fabrication hours.

“Working closely with our local suppliers, the standardized approach we adopted in designing the Cannonball and Mango platforms has delivered efficiencies and benefits in cost and time,” Riley said.

Three in a row

In mid-December 2007, bpTT started production on the nearby Cashima development, which comprises the Cashima field, discovered in 2001, and the North East Queens Beach (NEQB) field, discovered in 1975, both in 270 ft (80 m) of water. The fields were developed using a single unmanned platform of the same standardized design used for Cannonball and Mango. Cashima has capacity to produce from nine wells with gas exported through a new 11-mile (18-km) 26-in. pipeline to the Amherstia platform, which is being transformed into bpTT’s second central processing hub. The project will develop the hydrocarbon resources from the combined Cashima and NEQB fields.

The six Cashima development wells are based on the Cannonball standardized well design, but are at greater water depths and higher offsets. During operations the field is expected to add an incremental 750 MMcf/d of gas deliverability and some associated condensate.

“The Cashima development lives up to its name as a clone through the complete replication of the Cannonball concept with the added benefit of reducing cycle time from 36 months to 26 months,” said Adrian Clark, vice president, developments. “Applying the standardized concept has resulted in a 25% reduction in cycle time for new developments.”

Continued involvement

BPTT holds exploration and production licenses covering 904,000 acres in marine areas off Trinidad and Tobago’s east coast. The company’s total production in the region in 2007 was 450,000 boe/d, made up of oil, natural gas liquids and gas production.

Offshore production assets include 10 platforms and the Cassia B hub, which processes 2 bcf/d of gas at current capacity. Other processing hubs include Amherstia, with a capacity of 1.1 bcf/d and Mahogany with a capacity of 900 MMcf/d.

The eastern gas fields are served by two major offshore gas transmission service systems. BPTT owns and operates the larger system. The other is owned and operated by The National Gas Company of Trinidad and Tobago.

Hydrocarbons are transported to shore by pipeline. The bpTT gas transmission system consists of the 40-in. Mahogany-to-Beachfield and the 48-in. Cassia-to-Beachfield gas pipelines. The pipelines are connected at a subsea valve manifold at Cassia. Both Amherstia and Cassia have 20-in. spurs to the Mahogany-to-Beachfield pipeline. The Immortelle platform has separation facilities and separate gas and liquid pipelines to the Cassia hub.

The company’s objective is to build relationships and establish partnerships in Trinidad and Tobago and to incorporate domestic people, skills and resources in local projects. According to bpTT, this approach promises sustainability beyond the involvement of the company.

In 2006 bpTT contributed 14.4% to the country’s gross domestic product, 25% of government revenue, and accounted for 32% of the petroleum sector activity.