(19)

(11)

EP 0 897 546 A1

(12)

(43) Date of publication: 24.02.1999 Bulletin 1999/08 (21) Application number: 97917967.0 (22) Date of filing: 07.05.1997

(51) International Patent Classification (IPC):  G01V 1/ 00( . ) (86) International application number: PCT/CA1997/000315 (87) International publication number: WO 1997/042525 (13.11.1997 Gazette 1997/49)

(84) Designated Contracting States: AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE (30) Priority: 08.05.1996 CA 19962176058 (71) Applicant: Pancanadian Petroleum Limited Calgary, Alberta T2P 2S5 (CA)	(72) Inventors: GOODWAY, William, Nicholas Calgary, Alberta T3H 3A3 (CA) RAGAN, Brent, Roland Calgary, Alberta T2X 2X4 (CA) (74) Representative: Smith, Samuel Leonard  J.A. Kemp & Co., 14 South Square, Gray's Inn London WC1R 5LX London WC1R 5LX (GB)