Appraisal drilling proves further gas at Cygnus

GDF Suez E&P has increased reserves at its Cygnus gas field in the UK southern North Sea.

Offshore staff

ABERDEEN -- GDF Suez E&P has increased reserves at its Cygnus gas field in the UK southern North Sea.

According to partner Endeavour International, appraisal drilling in the western area of the field in block 44/11a has led to a preliminary estimate of proven and prospective resources to 2 tcf, making Cygnus one of the largest gas discoveries ever in the UK southern gas basin.

Well 44/11a-4 well was drilled to a depth of 12,207 ft (3,721 m) vertical depth subsea, encountering a gas-saturated Leman sand reservoir 54 ft (16.4 m) high to prognosis with a sand thickness of 130 ft (39.6 m) gross and 85 ft (26 m) net. The well was flow tested at a rate of 28 MMcf/d.

The discovery well and five appraisal wells drilled to date support a common field-wide gas water contact within around 10 ft (3 m), apart from the 44/11-2 well in the extreme southwest.

"This significant extension of the Cygnus field allows us to develop the area with a simplified, compressed, and lower-cost development and higher initial production rates that will accelerate to peak production levels more quickly," says William L. Transier, Endeavour’s CEO and president.

On completing operations, the rig will be mobilized to the southern part of Cygnus to drill the 44/12a-E appraisal well. The Cygnus group plans to acquire a new field-wide 3-D seismic survey over the field’s expanded boundaries. GDF Suez E&P is license operator, in partnership with Endeavour and Centrica.

4/15/2010

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