(19)

(11)

EP 3 464 790 A1

(12)

(43) Date of publication: 10.04.2019 Bulletin 2019/15 (21) Application number: 17727349.7 (22) Date of filing: 26.05.2017

(51) International Patent Classification (IPC):  E21B 27/02(2006.01) (86) International application number: PCT/GB2017/051517 (87) International publication number: WO 2017/203287 (30.11.2017 Gazette 2017/48)

(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: 26.05.2016 GB 201609286 (71) Applicant: Metrol Technology Limited Aberdeen, Aberdeenshire AB21 0GU (GB)	(72) Inventors: ROSS, Shaun Compton Aberdeen Aberdeenshire AB15 9ES (GB) JARVIS, Leslie David Stonehaven Aberdeenshire AB39 2GJ (GB) (74) Representative: HGF Limited  1 City Walk Leeds LS11 9DX Leeds LS11 9DX (GB)