(19)

(11)

EP 3 414 421 A1

(12)

(43) Date of publication: 19.12.2018 Bulletin 2018/51 (21) Application number: 17704476.5 (22) Date of filing: 13.02.2017

(51) International Patent Classification (IPC):  E21B 33/035(2006.01) E21B 34/04(2006.01) E21B 33/06(2006.01) (86) International application number: PCT/EP2017/053136 (87) International publication number: WO 2017/137622 (17.08.2017 Gazette 2017/33)

(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 Designated Validation States: MA MD (30) Priority: 12.02.2016 NO 20160250 (71) Applicant: BTI AS 5237 Rådal (NO)	(72) Inventors: DAHLE, Bjørn, Olav 5237 Rådal (NO) LIEN, Birger, W-F. 5081 Bergen (NO) (74) Representative: Onsagers AS  P.O. Box 1813 Vika 0123 Oslo 0123 Oslo (NO)