(19)

(11)

EP 1 149 225 A1

(12)

(43) Date of publication: 31.10.2001 Bulletin 2001/44 (21) Application number: 00910636.0 (22) Date of filing: 01.02.2000

(51) International Patent Classification (IPC)7: E21B 43/10 (86) International application number: PCT/EP0000/791 (87) International publication number: WO 0046/484 (10.08.2000 Gazette 2000/32)

(84) Designated Contracting States: AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE (30) Priority: 01.02.1999 EP 99300717 (71) Applicant: SHELL INTERNATIONALE RESEARCHMAATSCHAPPIJ B.V. 2596 HR Den Haag (NL)	(72) Inventors: VAN BUREN, Markus Antonius 113 Muscat (OM) SUREWAARD, Johannes Henricus Gerardus 113 Muscat (OM)