(19)
(11) EP 0 211 925 A1

(12)

(43) Date of publication:
04.03.1987 Bulletin 1987/10

(21) Application number: 86901528.0

(22) Date of filing: 21.02.1986
(51) International Patent Classification (IPC): 
E21B 7/ 04( . )
E21B 17/ 00( . )
(86) International application number:
PCT/NO1986/000019
(87) International publication number:
WO 1986/004950 (28.08.1986 Gazette 1986/19)
(84) Designated Contracting States:
DE FR GB IT NL SE

(30) Priority: 21.02.1985 NO 19850000689

(71) Applicant: A/S RAUFOSS AMMUNISJONSFABRIKKER
N-2831 Raufoss (NO)

(72) Inventor:
  • SANGESLAND, Sigbjorn
    N-7000 Trondheim (NO)

   


(54) DRILLING PIPE FOR MAKING A DRILL STRING