Top drive sheave method and apparatus

Abstract

A traveling top drive sheave system includes in one embodiment a rig carrier, a mast assembly pivotally attached to the rig carrier comprising guide rails and a crown block, a top drive fixture, and a traveling sheave block. The mast assembly is moveable to a generally perpendicular position with respect to the rig carrier, providing the top drive access to a wellhead. The top drive is mounted within the mast assembly and is supported along guide rails to be vertically moveable along a same axis as the wellhead. In one embodiment, the traveling sheave block has an axis offset from the crown block to enhance the reeving of a drilling line between both blocks. In another embodiment, the system contains guide rails and rollers whereby at least one of the rollers or guide rails has a groove and the other is sized to mate with said groove for facilitating vertical movement along said mast assembly.

What is claimed is: 
     
         1 . A top drive traveling sheave system and method, comprising:
 a rig carrier;   a mast assembly pivotally mounted to said rig carrier comprising at least a first guide rail and a second guide rail, said mast assembly being moveable between a lowered position and a raised position;   a top drive;   a rotor for said top drive;   a top drive fixture mounted within said mast assembly, said top drive fixture supporting said top drive;   guide members mounted with respect to said top drive fixture for engaging said first guide rail and said second guide rail to limit rotation of said top drive whereby said rotor is constrained to move substantially along a consistent path as said top drive moves up and down in said mast assembly; and   a plurality of traveling sheaves mounted with respect to a top side of said top drive fixture and being centrally located with respect to said top fixture.   
     
     
         2 . The top drive traveling sheave system of  claim 1 , further comprising a crown block mounted to a top end of said mast assembly, said crown block comprising a group of uniformly spaced sheaves. 
     
     
         3 . The top drive traveling sheave system of  claim 1 , wherein said guide members comprise wheels. 
     
     
         4 . The top drive traveling sheave system of  claim 1 , wherein said guide members comprise frames which engage said guide members. 
     
     
         5 . The top drive traveling sheave system of  claim 1 , further comprising crown sheave wheels, said crown sheave wheels rotating about a first axis of rotation, said traveling sheaves rotating about a second axis of rotation, said first axis of rotation and said second axis of rotation being angularly oriented differently from each other. 
     
     
         6 . The top drive traveling sheave system of  claim 5 , wherein said first axis of rotation and said second axis of rotation are angularly oriented with respect to each other with an offset of less than ninety degrees. 
     
     
         7 . A top drive traveling sheave system and method, comprising:
 a rig carrier;   a mast assembly pivotally mounted to said rig carrier comprising at least a first guide rail and a second guide rail, said mast assembly being moveable between a lowered position and a raised position;   a top drive;   a top drive fixture mounted within said mast assembly, said top drive fixture supporting said top drive; and   at least a first set of rollers and a second set of rollers, said first set of rollers being mounted to move with said top drive fixture, at least one of said first set of rollers or said first guide rail comprising a groove and the other of said first guide rail or said first set of rollers comprising a profile for at least substantially mating with said groove whereby said first set of rollers facilitates vertical movement of said top drive fixture along said first guide rail with respect to said mast assembly and limits rotation of said top drive fixture, said second set of rollers being mounted to move with said top drive fixture, at least one of said second set of rollers or said second guide rail comprising a groove and the other of said second guide rail or said second set of rollers comprising a profile for at least substantially mating with said groove whereby said second set of rollers facilitates vertical movement of said top drive fixture along said second guide rail with respect to said mast assembly and limits rotation of said top drive fixture.   
     
     
         8 . The top drive traveling sheave system of  claim 7 , further comprising a plurality of traveling sheave wheels mounted centrally with respect to a top side of said top drive fixture, said plurality of traveling sheave wheels being evenly spaced apart. 
     
     
         9 . The top drive traveling sheave system of  claim 8 , further comprising a crown mounted to a top end of said mast assembly, said crown comprising a plurality of crown sheave wheels evenly spaced apart for reeving a drilling line. 
     
     
         10 . The top drive traveling sheave system of  claim 9 , wherein said plurality of traveling sheave wheels rotate around a first axis of rotation, said plurality of crown sheave wheels rotate around a second axis of rotation, said first axis being oriented in a different direction than said second axis. 
     
     
         11 . The top drive traveling sheave system of  claim 8 , wherein said plurality of traveling sheave wheels comprise a diameter less than 20 times a diameter of a drilling line. 
     
     
         12 . The top drive traveling sheave system of  claim 7 , whereby said rig carrier has a height of less than 20 feet when said mast assembly is in said lowered position. 
     
     
         13 . The top drive traveling sheave system of  claim 7 , further comprising at least a first contact member mounted to said top drive fixture whereby said first contact member at least occasionally contacts at least one of said first guide rail and said second guide rail to absorb torque created by top drive and limits rotation of said top drive fixture during operation thereof. 
     
     
         14 . A top drive traveling sheave system, comprising:
 a mast assembly;   a plurality of crown sheaves mounted to a top of said mast assembly and having a first axis of rotation;   a top drive;   a top drive fixture mounted within said mast assembly, said top drive fixture supporting said top drive; and   a plurality of traveling sheaves mounted to move with said top drive fixture, said traveling sheaves rotating about a second axis of rotation, said first axis of rotation and said second axis of rotation are angularly oriented with respect to each other with an offset of less than ninety degrees.   
     
     
         15 . The top drive traveling sheave system of  claim 14 , wherein said mast assembly further comprises a first guide rail and a first set of rollers, said first set of rollers being mounted for movement with said top drive fixture, at least one of said first set of rollers or said first guide rail comprising a groove and the other of said first guide rail or said first set of rollers comprising a first profile for substantially mating with said groove whereby said first set of rollers facilitates vertical movement of said top drive fixture along said first guide rail with respect to said mast assembly while limiting rotation of said top drive fixture. 
     
     
         16 . The top drive traveling sheave system of  claim 15 , further comprising a second guide rail, a second set of rollers mounted for movement with said top drive fixture, at least one of said second set of rollers or said second guide rail comprising a groove and the other of said second guide rail or said second set of rollers comprising a second profile for mating with said groove whereby said second set of rollers facilitates vertical movement of said top drive fixture along said second guide rail with respect to said mast assembly. 
     
     
         17 . The top drive traveling sheave system of  claim 15 , further comprising a plurality of traveling sheave wheels mounted to said top drive fixture, said plurality of sheave wheels having a diameter less than 20 times a diameter of a drilling line. 
     
     
         18 . The top drive traveling sheave system of  claim 15 , further comprising at least a first contact member mounted to said top drive fixture whereby said first contact member contacts said mast assembly to absorb torque created by said top drive and prevent rotation of said top drive fixture during operation thereof. 
     
     
         19 . The top drive traveling sheave system of  claim 15 , further comprising a rig carrier, said mast being moveable between a lowered position and a raised position, whereby said rig carrier has a height of less than 20 feet when said mast assembly is in said lowered position.