Patent ID: 6224112
Filing Date: 2001-05-01
Classification: E21B

Abstract:
A casing slip joint comprising an outer casing and an inner casing releasably secured together by at least one fastener, the at least one fastener a self-destructive apparatus comprising a first outer shear member extending between said inner casing and said outer casing, said first outer shear member provided with an inner recess, wherein said at least one fastener further comprises an inner member in said inner recess, the first outer shear member made of a first metal and the inner member made of a second metal different from the first metal so that upon contact of the first outer shear member and inner member by an electrolyte an electrolytic cell is created that results in damage to the first outer shear member to facilitate shearing of the first outer shear member to release the outer casing from the inner casing.