Well casing guide string and repair method
First Claim
1. An assembly for repairing a casing section disposed in a wellbore comprising:
- an elongated tubular guide string adapted to be inserted in said casing;
a casing milling tool connected to a work string for rotation to machine the upper end of said casing; and
a swivel interconnecting said guide string and said work string including said milling tool whereby said guide string is connected to said milling tool and said work string but is rotationally independent of the rotation of said work string and said milling tool.
1 Assignment
0 Petitions
Accused Products
Abstract
Well casing is repaired using a guide string for maintaining contact with a lower casing section disposed in the well, particularly an open hole portion of such well. The guide string is connected to a swivel and milling tool and lowered into the casing section remaining in the open hole portion of the well for machining the upper end of the casing section. The swivel prevents build-up of angular momentum of the guide string which may decouple the guide string from the milling tool when the milling tool rotatably decelerates or snags during the machining or milling operations. The milling tool and swivel may be retrieved and the guide string, with a safety joint or fishing head, reinserted in the well during installation of a new casing section.
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Citations
6 Claims
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1. An assembly for repairing a casing section disposed in a wellbore comprising:
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an elongated tubular guide string adapted to be inserted in said casing; a casing milling tool connected to a work string for rotation to machine the upper end of said casing; and a swivel interconnecting said guide string and said work string including said milling tool whereby said guide string is connected to said milling tool and said work string but is rotationally independent of the rotation of said work string and said milling tool. - View Dependent Claims (2, 3)
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4. A method for repairing a well casing which includes a first section having an upward facing end and a second section which is disposed generally above said first section;
- said method comprising;
inserting a guide string within said well casing and extending into said first casing section, said guide string having an upper end extending above said upward facing end of said first casing section; removing said second casing section from said wellbore; lifting said guide string partially out of said first casing section and connecting a milling tool and swivel to said guide string; lowering the assembly of said milling tool, said swivel, and said guide string into said first casing section and engaging said milling tool with said first casing section; and rotating said milling tool to machine said upper end of said first casing section while permitting free rotative movement of said guide string relative to said milling tool. - View Dependent Claims (5, 6)
- said method comprising;
Specification