Internal tubing cutter

Abstract

Implementations of the present invention include an internal tubing cutter including ramp surface(s) and roller that cause cutters to move linearly between retracted and deployed positions. The linear actuation of the cutters can allow for more robust cutting and increased cutting efficiency. Implementations of the present invention also include cutting systems including an internal tubing cutter, and methods of cutting tubular members, such as borehole casings and drill strings, using such drilling systems.

We claim: 
     
         1 . An internal tubing cutter, comprising:
 a tubular body having a first end and a lower end;   at least one cartridge opening extending through the tubular body;   a cutter cartridge at least partially positioned within the at least one cartridge opening, the cutter cartridge including a cutter and at least one axially tapered ramp surface;   an inner member configured to move relative to the cutter cartridge; and   at least one roller positioned between the ramp surface and the inner member;   wherein axial displacement of the inner member relative to the cutter cartridge causes the at least one roller to move along the ramp surface thereby linearly moving the cutter cartridge radially from a retracted position within the tubular body to a deployed position in which the cutter is at least partially radially outward of the tubular body.   
     
     
         2 . The internal tubing cutter as recited in  claim 1 , wherein the cutter comprises a disc blade. 
     
     
         3 . The internal tubing cutter as recited in  claim 2 , further comprising a pivot pin adapted to couple the disc blade to the cutter cartridge and allow the disc blade to rotate relative to the cutter cartridge. 
     
     
         4 . The internal tubing cutter as recited in  claim 1 , wherein the cutter cartridge comprises a diamond shape. 
     
     
         5 . The internal tubing cutter as recited in  claim 1 , wherein the at least one axially tapered ramp surface comprises an upper ramp surface positioned on an upper end of the cutter cartridge and a lower ramp surface positioned on a lower end of the cutter cartridge. 
     
     
         6 . The internal tubing cutter as recited in  claim 5 , wherein each of the upper and lower ramp surfaces extend radially outward and axially toward the first end of the tubular body. 
     
     
         7 . The internal tubing cutter as recited in  claim 5 , further comprising:
 a wedge return; and   a second roller positioned between the lower ramp surface and the wedge return;   wherein axial displacement of the wedge return relative to the cutter cartridge causes the second roller to move along the lower ramp surface thereby linearly moving the cutter cartridge radially from the deployed position to the retracted position.   
     
     
         8 . The internal tubing cutter as recited in  claim 7 , further comprising a biasing member configured to bias the wedge return toward the cutter cartridge. 
     
     
         9 . The internal tubing cutter as recited in  claim 7 , wherein the wedge return comprises an axially tapered surface against which the second roller is positioned. 
     
     
         10 . The internal tubing cutter as recited in  claim 1 , further comprising a valve stop positioned within the inner member, the value stop being configured to create a seal with the inner member and prevent the passage of fluid through the tubular body. 
     
     
         11 . The internal tubing cutter as recited in  claim 10 , further comprising one or more fluid flow passages extending through the tubular body. 
     
     
         12 . The internal tubing cutter as recited in  claim 11 , wherein the inner member is configured to block the one or more fluid flow passages when the cutter cartridges are in the refracted position. 
     
     
         13 . The internal tubing cutter as recited in  claim 1 , wherein:
 the inner member comprises an inner wedge and an outer wedge; and   the at least one roller is positioned in a mounting slot in the outer wedge.   
     
     
         14 . An internal tubing cutting system, comprising:
 a generally hollow body;   a plurality of cartridge openings extending through the body;   a plurality of cutter cartridges configured to hold one or more cutters, each cutter cartridge being positioned in a cartridge opening of the plurality of cartridge openings;   an inner member;   a plurality of rollers positioned between the cutter cartridges and the inner member, each roller of the plurality of rollers being positioned against a ramp surface;   wherein movement of the inner member relative to the cutter cartridges causes the plurality of rollers to move along the ramp surface thereby linearly moving the plurality of cutter cartridges at least partially radially outward of the plurality of cartridge openings.   
     
     
         15 . The internal tubing cutting system as recited in  claim 14 , wherein the ramp surface comprises an outer surface of the inner member. 
     
     
         16 . The internal tubing cutting system as recited in  claim 15 , wherein the outer surface of the inner member is a conical surface. 
     
     
         17 . The internal tubing cutting system as recited in  claim 14 , wherein the ramp surface comprises a plurality of ramp surfaces on upper ends of each cutter cartridge. 
     
     
         18 . The internal tubing cutting system as recited in  claim 17 , further comprising a plurality of lower ramp surfaces, the lower ramp surfaces being positioned on lower ends of cutter cartridge. 
     
     
         19 . The internal tubing cutting system as recited in  claim 18 , wherein each of the plurality of ramp surfaces and the plurality of lower surfaces extend radially outward and axially toward a first of the tubular body. 
     
     
         20 . The internal tubing cutting system as recited in  claim 19 , further comprising:
 a wedge return; and   a plurality of second rollers positioned between the plurality of lower ramp surfaces and the wedge return;   wherein axial displacement of the wedge return relative to the cutter cartridges causes the second rollers to move along the lower ramp surfaces thereby linearly moving the cutter cartridges radially from the deployed position to the refracted position.   
     
     
         21 . The internal tubing cutting system as recited in  claim 20 , further comprising a biasing member configured to bias the wedge return toward the cutter cartridges. 
     
     
         22 . The internal tubing cutting system as recited in  claim 14 , wherein the plurality of rollers are positioned at least partially within the inner member. 
     
     
         23 . The internal tubing cutting system as recited in  claim 14 , wherein the plurality of rollers are positioned at least partially within the cutter cartridges of the plurality of cutter cartridges. 
     
     
         24 . A method of cutting a tubular member, comprising:
 lowering an internal tubing cutter into the tubular member;   pumping a fluid into the internal tubing cutter to cause an inner member to move axially within a body of the internal tubing cutter, wherein axial movement of the inner member causes one or more rollers operatively associated with the inner member to move along a ramp surface of a cutter cartridge thereby moving a cutter linearly at least partially outward of the internal tubing cutter; and   rotating the internal tubing cutter relative to the tubular member thereby causing the cutter held within the cutter cartridge to cut the tubular member.   
     
     
         25 . The method as recited in  claim 24 , further comprising causing the cutter to rotate about two parallel and offset axes. 
     
     
         26 . The method as recited in  claim 25 , wherein causing the cutter to rotate about two parallel and offset axes comprises causing the cutter:
 to rotate about a pivot pin extending securing the cutter to the cutter cartridge; and   orbit about a central axis of the internal tubing cutter.   
     
     
         27 . The method as recited in  claim 24 , further comprising pumping a fluid into the internal tubing cutter so as to move the inner member beyond one or more fluid flow passages extending through the body thereby causing a pressure drop in the fluid. 
     
     
         28 . The method as recited in  claim 27 , further comprising biasing a wedge return toward the cutter cartridge such that upon the pressure drop in the fluid the wedge return automatically moves the cutter linearly into the internal tubing cutter.