Gas Condensate Field
Block 23/16f in the Central North Sea was awarded to Serica and its partners in 2005 in the 23rd Round of UK Offshore Licensing. Block 23/21a (part), also known as ‘Columbus Sub Area’ was purchased by the 23/16f owners in October 2015. Serica’s partners in the blocks are Endeavour Energy UK Limited (25%) and EOG Resources United Kingdom Limited (25%).
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 side-tracked (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 Block 23/21a (part), and proved the extension of the Columbus Field into the block.