(19)

(11)

EP 4 824 383 A1

(12)

(43) Date of publication: 21.10.2026 Bulletin 2026/43 (21) Application number: 24827041.5 (22) Date of filing: 10.12.2024

(51) International Patent Classification (IPC):  E21B 4/18(2006.01) E21B 4/04(2006.01) E21B 23/14(2006.01) E21B 7/26(2006.01) E21B 23/00(2006.01) E21B 25/02(2006.01) (52) Cooperative Patent Classification (CPC): E21B 4/18; E21B 7/26; E21B 4/04; E21B 23/001; E21B 23/14; E21B 25/02 (86) International application number: PCT/EP2024/085529 (87) International publication number: WO 2025/125240 (19.06.2025 Gazette 2025/25)

(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 ME MK MT NL NO PL PT RO RS SE SI SK SM TR Designated Extension States: BA Designated Validation States: GE KH MA MD TN (30) Priority: 15.12.2023 WO PCT/EP2023/086190 (71) Applicant: HSRD AG 5400 Baden (CH)	(72) Inventor: HALLER, Walter 8907 Wettswil (CH) (74) Representative: Rentsch Partner AG  Kirchenweg 8 Postfach 8034 Zürich 8034 Zürich (CH)