Category: Archive

Off the coast of Co. Mayo, gas in them thar waters

February 16, 2011

By Staff Reporter

By Andrew Bushe

DUBLIN – A big offshore gas find by a consortium led by the British

exploration company Enterprise Oil is expected to substantially reduce the country’s dependency on imported energy and give a major boost to the Celtic Tiger economy in the new millennium.

As the Kinsale gas field discovered off Cork by the U.S. Marathon company in the early 1970s begins to wind down to the end of its production life in about 2006, supply is dropping.

About 50 per cent of the country’s gas needs are being imported by sub-sea pipeline from Britain this year.

The SEDCO 711 rig hit gas again last week with an appraisal well in 1,100 feet of water on the southern end of the Corrib field — 55 km (34 miles) off Co Mayo — for the consortium which also includes Marathon, Statoil and Saga.

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Gas flowed at a rate of 64 million standard cubic feet (scf) per day, which would be equivalent to over a fifth of Ireland’s peak daily needs.

A well on the center of the Corrib structure last year flowed 63 million scf of gas a day. As well as being exploration wells, the two drillholes are also capable of being used as production wells. Together the two wells would supply up to 50 per cent of the country’s requirements.

The rig is now moving 8 km or five miles south to carry out the first exploratory well on a new prospect called Shannon, which they hope is related to the Corrib geological structure.

While not directly connected, it is at a similar depth of about 12,000 below the seabed and has similar geology and could be developed as a "satellite" to Corrib.

Enterprise Oil’s Irish general manager John McGoldrick said the gas would be produced by sub-sea structures, as it would be too expensive to put a platform in such deep water.

"It’s a very positive result. We have invested already, or gambled some might say, £80 million to get this far. We need to invest a further £400 million to get the gas to market," he said.

The whole offshore Mayo operation could prove to be bigger than Kinsale. Industry estimates have suggested that Corrib could contain 1.2 trillion cubic feet of gas and Shannon 0.8 trillion cubic feet. Kinsale had reserves of about 1.4 trillion cubic feet.

A statement from Enterprise said the results require further evaluation but have demonstrated enough reserves to begin development studies.

The Corrib find dramatically changes the energy market and leaves a question mark over Bord Gais’s plan for a £300 million second inter-connector pipeline from Britain.

When the Corrib gas comes ashore in two to three years time, Enterprise plan to lay their own onshore pipeline and challenge the Bord Gais distribution monopoly.

The Shannon well will be the sixth off Ireland for the Enterprise-led consortium. They have also drilled on the Kish Bank off Dublin and in another prospect called Avonmore off the west coast.

So far, 131 exploration wells have been drilled off Ireland, most of them in the Celtic Sea off the south coast.

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