公开(公告)号：CA2296486A1

公开(公告)日：1999-01-28

申请号：CA2296486

申请日：1998-07-20

Applicant: WEATHERFORD LAMB

Inventor： MAHMOUD SALAH ,  HAUGEN DAVID ,  ERIKSEN ERIK PETER

IPC: E21B17/046 ,  E21B17/06

Abstract: A fastener for use in an oil tool between a first member (20) and a second member (30), said fastener comprising an outer member (50) which, in use, extends between said first member (20) and said second member (30), characterised in that said outer member (50) is provided with an inner recess (51).

公开(公告)号：AU8448098A

公开(公告)日：1999-02-10

申请号：AU8448098

申请日：1998-07-20

Applicant: WEATHERFORD LAMB ,  LUCAS BRIAN RONALD

Inventor： HAUGEN DAVID ,  ERIKSEN ERIK PETER VESTERGAAD ,  MAHMOUD SALAH

IPC: E21B17/046 ,  E21B17/06

Abstract: A casing slip joint has been invented that has a first tubular casing member disposed around and releasably connected to a second casing member, the second casing member within and surrounded by the first casing member. Self-destructive shear screws according to the present invention releasably hold the first casing member to the second casing member. In one aspect, a shear screw according to this invention has an outer shear screw with a central recess and an inner member therein. In one aspect the outer shear screw is made of one metal and the inner screw is made of another so that contact by a well fluid sets up a galvanic cell that produces stress corrosion cracking in the outer shear screw that weakens it and/or destroys it. The propagation of such cracks is facilitated by placing one or more notches or recesses in the body of the components.