Block 23/16f Columbus

Serica 50% (operator), Endeavour 25%, EOG 25%

Block 23/16f covers an area of approximately 52 square kilometres in the Central North Sea and was awarded to Serica and its partners in 2005 in the 23rd Round of UK Offshore Licensing.

In late 2006 Serica drilled the Columbus discovery well 23/16f-11 to a depth of 10,116 feet subsea and encountered a gross gas column of 125 feet in the Palaeocene Forties sands.  The well was tested and, during the main five-hour flow period on a restricted choke of 56/64”, produced at a stabilised average rate of 17.5 mmscfd and 1,060 bpd of 47.5° API condensate with a wellhead pressure of 1,200 psi.

In 2007 Well 23/16f-12 was drilled as a vertical appraisal well approximately three kilometres north of the Columbus discovery well, and encountered gas/condensate-bearing Palaeocene sands at a higher elevation than those tested in well 23/16f-11.  A full evaluation of the hydrocarbon-bearing interval was carried out and reservoir fluid samples were obtained.

To further evaluate the Columbus discovery, the 23/16f-12 well was then sidetracked (as 23/16f-12z) to a bottom-hole location approximately two kilometres north of the Columbus discovery well and encountered gas/condensate-bearing Palaeocene sands similar to those found in 23/16f-11.  Reservoir fluid samples were obtained and the well was suspended for potential use in the development of Columbus.

In December 2008, BG International ("BG") drilled an appraisal well (23/21-7x) in the northern part of Block 23/21, immediately to the south of Block 23/16f and proved the extension of the Columbus Field into Block 23/21.