(19)

(11)

EP 2 971 455 A2

(12)

(88) Date of publication A3: 08.01.2015 (43) Date of publication: 20.01.2016 Bulletin 2016/03 (21) Application number: 14713238.5 (22) Date of filing: 14.03.2014

(51) International Patent Classification (IPC):  E21B 21/10(2006.01) E21B 34/14(2006.01) E21B 23/04(2006.01) (86) International application number: PCT/GB2014/050780 (87) International publication number: WO 2014/140605 (18.09.2014 Gazette 2014/38)

(84) Designated Contracting States: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR Designated Extension States: BA ME (30) Priority: 15.03.2013 GB 201304790 (71) Applicant: Petrowell Limited Aberdeen AB12 3LF (GB)	(72) Inventors: WEBSTER, Oliver Torphins Aberdeen AB31 4HH (GB) PURKIS, Daniel George Cruden Bay Aberdeen AB42 0QH (GB) PATTON, Damien Gerard Huntly Aberdeen AB54 4NL (GB) MANNING, Matthew Dyce Aberdeen AB21 0DR (GB) (74) Representative: Docherty, Andrew John  Marks & Clerk LLP Aurora 120 Bothwell Street Glasgow G2 7JS Glasgow G2 7JS (GB)