Projects

Exxon-East Area NGL II – Bonny Island, Nigeria

ExxonMobil affiliate Mobil Producing Nigeria Unlimited (MPN) is the operator, with a 51% interest, of this joint ven

Location

Bonny Island, about 28km off southeast Nigeria

Blocks

OML 67, 68 and 70

Water depth

26-34m

No of wells

353

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ExxonMobil affiliate Mobil Producing Nigeria Unlimited (MPN) is the operator, with a 51% interest, of this joint venture with the Nigerian National Petroleum Corporation (NNPC). The project is located about 28km offshore Nigeria and on Bonny Island, Nigeria.

MPN is the only big oil company operating completely offshore Nigeria, and holds more than 800,000 acres in water depths of 26-34m, off the southeast of the country. Production comes from 90 offshore platforms, with 283 flowing completions in 353 wells with a production capacity of about 720,000 barrels of crude, condensate and natural gas liquid (NGL) a day.

The $1.3bn project is designed to gather gas from all the MPN fields, compress, extract NGL and inject lean gas to recover 275m barrels of natural gas liquids from associated gas produced in the East Area reservoirs from blocks OML 67, 68 and 70. It uses about 950Mmscf of gas a day.

Geology

The three blocks lie on top of one of the Niger Delta’s depositional prisms, a young Cenozoic complex that was built out over newly formed oceanic crust as the South Atlantic opened during the separation of the South American and African tectonic plates.

Following the opening of the South Atlantic, vast quantities of clastic sediments were poured into the delta, giving rise to three main rock units, which were deposited as prograded wedges. The middle unit, the Agbada formation, is the delta’s main reservoir unit and consists of shallower water marine sands and lagoonal sands and shales.

The Cenozoic complex is notable for its development of growth faults, which have produced the traps for its oil and gas fields and which are not present in the other two rock units.

The main components of the project include an offshore NGL extraction platform, called GX, more than 200km of new natural gas and NGL pipelines of various diameters, and expansion of the existing onshore Bonny River Terminal.

“NGL production began in March 2008.”

At the GX platform, the gas is cooled and liquefied. Saleable liquids are piped to shore and exported through the Bonny River Terminal, while the remaining gas is piped a short distance to the gas compression platform.

On the compression platform, the gas is pressurised to return to the outlying platforms and into the wells, where it increases the pressure in the wells to boost oil production, saving the gas for future use.

The project is part of MPN’s aim to reduce gas flaring, in conjunction with the existing and neighbouring East Area Additional Oil Recovery (AOR) project, which started in June 2006.

NGL production began in March 2008 and, at its peak, the project will produce about 50,000 barrels of natural gas liquids a day.

The project also represents the first time that a big oil and gas joint venture in Nigeria has used funding from Nigerian financial institutions – about $220m of the project’s total. No full list of the institutions is available but MPN has said that it worked with the NNPC to develop and implement funding solutions to support the growth of the industry and enhance the Nigerian Government’s goal of increasing production volumes.

Nigerian companies also provided in-country fabrication, logistics support and other services, as well as training and development of employees and contractors for the project.

Fabrication of the riser jacket and deck were completed in Warri, Nigeria by Acergy-owned Globestar; Socotherm Nigeria completed the coating of the 200km pipeline; Tvonne Nigeria Ltd completed the 10km of onshore pipe lay at Bonny Island; Dredging Services Nigeria completed the cofferdam and shore approach for the pipeline; and the floating dock was fabricated in Port Harcourt.

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