Method and apparatus for drilling and servicing subterranean wells with rotating coiled tubing

Abstract

A system is provided for drilling and/or servicing a well bore using continuous lengths of coiled tubing in which a turntable assembly rotates a coiled tubing reel assembly and a counter balance system about the well bore such that the coiled tubing is rotated while in the wellbore. A coiled tubing injector may be provided on a separate turntable assembly or on the same turntable assembly as the reel assembly.

1 . A system for drilling or servicing an under balanced or overbalanced well with coiled tubing, comprising:
 a rotatable base comprising a bearing system rotatably fixing the base to a floor,   a reel assembly comprising a support structure adapted to support a reel of coiled tubing, the support structure comprising an alignment system to align the coiled tubing with the well as the coiled tubing is payed on and off the reel; reel, the reel assembly located near a periphery of the base;   a coil tubing injector head disposed adjacent the reel assembly and aligned with the well;   a counterbalance assembly located on the base substantially opposite the reel assembly and moveable toward and away from the reel assembly to maintain balance of the rotatable base as coiled tubing is payed on and off the reel; and   a motive system for turning the base and thereby transmitting torque to the coiled tubing in the well.   
   
   
       2 . The system of  claim 1 , further comprising a second rotatable base to which the injector is coupled, and wherein the first rotatable base and the second rotatable base are capable of relative rotation there between. 
   
   
       3 . The system of  claim 2 , further comprising a torque measurement system adapted to determine an amount of reactive torque on the tubing in the well. 
   
   
       4 . The system of  claim 1 , wherein the alignment system comprises a first set of one or more hydraulic cylinders that move the reel toward the well as coiled tubing is payed off and a second set of one or more hydraulic cylinders that translate the reel relative to the well as coiled tubing is payed off. 
   
   
       5 . The system of  claim 2 , wherein the injector head further comprises a transducer system that detects the orientation of the coiled tubing relative to a centerline of the well and generates one or more signals for energizing the alignment system to bring the coiled tubing back into alignment. 
   
   
       6 . The system of  claim 1 , wherein the motive system comprises one or more hydraulic motors engaging a ring gear coupled to the base. 
   
   
       7 . The system of  claim 1 , wherein the motive system causes the base to rotate at a speed of about 0 to 20 rpm and generate a torque on the coiled tubing of up to about 13,000 foot-lbf. 
   
   
       8 . The system of  claim 1 , wherein the floor comprises a plurality of sections adapted to be repositioned for travel. 
   
   
       9 . The system of  claim 8 , further comprising a mobile rig. 
   
   
       10 . A system for drilling or servicing an under balanced or overbalanced well with rotating coiled tubing, comprising
 a platform assembly having a lower portion and an upper portion spaced above the lower portion;   a first rotatable base having an axis of rotation that substantially coincides with an axis of the well, the base disposed on the upper platform portion and comprising a bearing system rotatably fixing the base to the upper portion;   a reel assembly disposed on the first base comprising a support structure adapted to support a reel of coiled tubing, the support structure comprising an alignment system to align the reel coiled tubing in at least two directions with respect to the well as the coiled tubing is payed on and off the reel;   a coil tubing injector disposed on a second rotatable base having an axis of rotation that substantially coincides with an axis of the well, the coil tubing injector and the first base capable of relative rotation there between;   a counterbalance assembly located on the first rotatable base substantially opposite the reel assembly and moveable toward and away from the reel assembly and side to side relative to the reel assembly to maintain balance of the first rotatable base as coiled tubing is payed on and off the reel; and   a motive system for turning the first base and thereby transmitting torque to the coiled tubing in the well.   
   
   
       11 . The system of  claim 10 , further comprising a torque measurement system adapted to determine an amount of differential torque between the first and second rotatable base. 
   
   
       12 . The system of  claim 10 , wherein the injector further comprises a transducer system that detects the orientation of the coiled tubing relative to the axis of the well and generates one or more signals for energizing the alignment system to bring the coiled tubing back into alignment. 
   
   
       13 . The system of  claim 10 , wherein the motive system comprises one or more hydraulic motors engaging a ring gear coupled to the base. 
   
   
       14 . The system of  claim 13 , wherein the motive system causes the first base to rotate at a speed of about 0 to 20 rpm and generate a torque on the coiled tubing of up to about 13,000 foot-lbf. 
   
   
       15 . The system of  claim 10 , further comprising a mobile rig. 
   
   
       16 . The system of  claim 15 , wherein the floor comprises a plurality of sections adapted to be repositioned for travel. 
   
   
       17 . A method of drilling or servicing a well comprising:
 providing a first rotating structure associated with the floor and having an axis of rotation substantially aligned with an axis of the well, and comprising a coiled tubing reel assembly and a counterbalance assembly;   providing a second rotating structure associated with the first floor and having an axis of rotation substantially aligned with the well axis, and comprising a tubing injector;   uncoiling tubing off of the reel and into the injector;   injecting the uncoiled tubing into the well;   adjusting the position of the reel assembly to maintain the coiled tubing in substantial alignment with the well;   adjusting the counterbalance assembly to balance the first rotating structure as tubing is uncoiled; and   rotating the first rotating structure to thereby rotate the uncoiled tubing in the well.   
   
   
       18 . The method of  claim 17 , wherein the well is under balanced. 
   
   
       19 . The method of  claim 17 , wherein the well is overbalanced. 
   
   
       20 . The method of  claim 17 , further comprising determining any differential torque between the first rotating structure and the second rotating structure.