Centrica has announced the successful drilling of a second appraisal well in the western region of the Cygnus gas field, which is located in the UK Southern North Sea.

The company said the second appraisal well 44 / 12a-5 achieved a stabilised flow rate of 29 million standard cubic feet per day.

GDF Suez, operator of the field, said that Cygnus was now one of the most significant undeveloped gas fields in the UK Continental Shelf.

The Cygnus field is expected to contain reserves of 500 billion cubic feet to 1.2 trillion cubic feet of gas.

First gas from the eastern area of the field is scheduled for 2013, Centrica said.