(19)

(11)

EP 0 799 352 A1

(12)

(43) Date of publication: 08.10.1997 Bulletin 1997/41 (21) Application number: 95943228.0 (22) Date of filing: 22.12.1995

(51) International Patent Classification (IPC):  E02B 17/ 00( . ) E02B 17/ 02( . ) (86) International application number: PCT/EP1995/005162 (87) International publication number: WO 1996/020313 (04.07.1996 Gazette 1996/30)

(84) Designated Contracting States: GB IT SE (30) Priority: 23.12.1994 US 19940370764 23.12.1994 US 19940370763 23.12.1994 US 19940370767 (71) Applicant: SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ B.V. 2596 HR Den Haag (NL)	(72) Inventors: SMITH, Mark, Andrew Houston, TX 77079 (US) GALLAHER, Dale, Marion Metairie, LA 70003 (US) SGOUROS, George, Emanuel New Orleans, LA 70115 (US)