Method for cutting and retrieving pipe from a floating drill ship

Claim 1

A method for cutting and retrieving, from a floating drill ship, a well pipe disposed within a well bore and including connecting collars, wherein a cutter is utilized mounted on a drill string, said string including means for compensating for relative vertical movements between said ship and the well bore, said method comprising: lowering said drill string into the well bore to position said cutter in cutting relationship to said pipe, locating said cutter in spaced longitudinal relationship with respect to one of said collars in said pipe, anchoring said drill string, at a point between the cutter and the compensating means, at any desired depth within the well bore so as to prevent longitudinal displacement of said cutter while permitting rotation thereof, lowering said drill string from said ship to operatively position said compensating means, operating said cutter to sever said pipe, releasing said drill string from its anchored position, and utilizing said drill string to remove the severed pipe from the well bore.

Claim 2

A method for cutting and retrieving, from a floating drill ship, a well pipe disposed within a well bore and including connecting collars, wherein a cutter is utilized mounted on a drill string, said string including means for compensating for relative vertical movements between said ship and the well bore, said method comprising: lowering said drill string into the well bore to position said cutter in cutting relationship to said pipe, locating said cutter in spaced longitudinal relationship with respect to one of said collars in said pipe, anchoring said drill string, at a point between the cutter and the compensating means, at any desired depth within the well bore so as to prevent longitudinal displacement of said cutter while permitting rotation thereof, lowering said drill string from said ship to operatively position said compensating means, operating said cutter to sever said pipe, releasing said drill string from its anchored position, and utilizing said drill string to remove the severed pipe from the well bore.

Claim 7

An apparatus for use with a floating drill ship for making an outside cut on a pipe having connecting collars and disposed within a well bore and for retrieving the severed pipe section, comprising: a drill string adapted to be suspended from said drill ship, an outside cutter at the lower end of said drill string having at least one movable knife adapted to engage and cut said pipe, and being adapted to be actuated by pressurizing fluid supplied through said drill string, locater means carried by the drill string above said cutter for engaging a collar on said pipe to locate said cutter a spaced distance from said collar, swivel means for rotatably supporting said cutter and locater means within the well bore, said swivel means including anchor means for releasably anchoring said cutter and locater means at any desired depth to the wall of the well bore against lateral and longitudinal displacement within the well bore, and a telescoping joint in said drill string between said drill ship and said swivel means for compensating for vertical movement of said drill ship relative to said well bore.

Claim 8

An apparatus for use with a floating drill ship for making an outside cut on a pipe having connecting collars and disposed within a well bore and for retrieving the severed pipe section, comprising: a drill string adapted to be suspended from said drill ship, an outside cutter at the lower end of said drill string having at least one movable knife adapted to engage and cut said pipe, and being adapted to be actuated by pressurizing fluid supplied through said drill string, locater means carried by the drill string above said cutter for engaging a collar on said pipe to locate said cutter a spaced distance from said collar, swivel means for rotatably supporting said cutter and locater means within the well bore, said swivel means including anchor means for releasably anchoring said cutter and locater means at any desired depth to the wall of the well bore against lateral and longitudinal displacement within the well bore, and a telescoping joint in said drill string between said drill ship and said swivel means for compensating for vertical movement of said drill ship relative to said well bore.

Claim 9

A method for making an outside cut from a floating drill ship on a well pipe having connecting collars and disposed within a well bore, employing an outside cutter mounted on a drill string including a telescoping joint, said method comprising the steps of: lowering said drill string into the well bore to locate said cutter in surrounding relationship to said pipe, locating said cutter in spaced longitudinal relationship with respect to one of said collars, rotatably anchoring the drill string at any desired depth within the well bore against lateral and longitudinal displacement, lowering the drill string to operatively position said telescoping joint, operating the outside cutter to sever said pipe, releasing the drill string from its anchored position, and utilizing the drill string to remove the severed pipe from the well bore.

Claim 10

A method for making an outside cut from a floating drill ship on a well pipe having connecting collars and disposed within a well bore, employing an outside cutter mounted on a drill string including a telescoping joint, said method comprising the steps of: lowering said drill string into the well bore to locate said cutter in surrounding relationship to said pipe, locating said cutter in spaced longitudinal relationship with respect to one of said collars, rotatably anchoring the drill string at any desired depth within the well bore against lateral and longitudinal displacement, lowering the drill string to operatively position said telescoping joint, operating the outside cutter to sever said pipe, releasing the drill string from its anchored position, and utilizing the drill string to remove the severed pipe from the well bore.

Claim 15

An apparatus for use with a floating drill ship, for cutting and retrieving a pipe having connecting collars and disposed within a well bore, comprising: a drill string adapted to be suspended from said drill ship, means for compensating for relative vertical movement between said drill ship and the well bore, a cutter on said drill string having at least one movable knife adapted to engage and cut said pipe, locater means carried by the drill string for locating and engaging a collar on said pipe to locate said cutter a spaced distance from said collar, swivel means for rotatably supporting said cutter and locater means within the well bore, and anchor means on the swivel means for engaging the well wall at any desired depth for releasably anchoring said cutter, locater means and swivel against lateral and longitudinal displacement within the well bore.

Claim 16

An apparatus for use with a floating drill ship, for cutting and retrieving a pipe having connecting collars and disposed within a well bore, comprising: a drill string adapted to be suspended from said drill ship, means for compensating for relative vertical movement between said drill ship and the well bore, a cutter on said drill string having at least one movable knife adapted to engage and cut said pipe, locater means carried by the drill string for locating and engaging a collar on said pipe to locate said cutter a spaced distance from said collar, swivel means for rotatably supporting said cutter and locater means within the well bore, and anchor means on the swivel means for engaging the well wall at any desired depth for releasably anchoring said cutter, locater means and swivel against lateral and longitudinal displacement within the well bore.