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(11)

EP 3 563 033 A1

(12)

(43) Date of publication: 06.11.2019 Bulletin 2019/45 (21) Application number: 16829111.0 (22) Date of filing: 30.12.2016

(51) International Patent Classification (IPC):  E21B 41/02(2006.01) E21B 47/12(2012.01) E21B 41/00(2006.01) (86) International application number: PCT/GB2016/054097 (87) International publication number: WO 2018/122546 (05.07.2018 Gazette 2018/27)

(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 (71) Applicant: Metrol Technology Ltd Aberdeen, Aberdeenshire AB21 0GS (GB)	(72) Inventors: JARVIS, Leslie David Aberdeen Aberdeenshire AB21 0GS (GB) ROSS, Shaun Compton Aberdeen Aberdeenshire AB21 0GS (GB) HUDSON, Steven Martin Aberdeen Aberdeenshire AB21 0GS (GB) (74) Representative: CSY London  10 Fetter Lane London EC4A 1BR London EC4A 1BR (GB)