(19)

(11)

EP 1 064 604 A1

(12)

(43) Date of publication: 03.01.2001 Bulletin 2001/01 (21) Application number: 98961922.6 (22) Date of filing: 04.12.1998

(51) International Patent Classification (IPC)7: G06F 17/00, G06F 19/00 (86) International application number: PCT/US9825/819 (87) International publication number: WO 9930/249 (17.06.1999 Gazette 1999/24)

(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: 05.12.1997 US 65168 P (71) Applicant: SCHLUMBERGER TECHNOLOGY CORPORATION AustinTexas 78720-0015 (US)	(72) Inventor: KENYON, Christopher, M. Cedar Park, TX 78613 (US) (74) Representative: Stoole, Brian David  Geco-Prakla Technical Services Inc,Patent Department,Schlumberger House,Buckingham Gate Gatwick,West Sussex RH6 ONZ Gatwick,West Sussex RH6 ONZ (GB)