Method of drilling and running casing in large diameter wellbore

Abstract

A well is drilled and casing installed utilizing a casing drilling technique. A bottom hole assembly having a drill bit and a fluid diverter is secured to a string of drill pipe and installed within a casing string. Drilling fluid is pumped down the drill pipe string to cause the drill bit to rotate and drill the well while the fluid diverter is in a drilling mode position. At the total depth for the casing string, the operator moves the fluid diverter to a cementing position and pumps cement down the drill pipe and up the casing string annulus. After cementing, the operator moves the fluid diverter to a packer set position and again pumps drilling fluid down the drill string to set the packer.

1 . A method of drilling a well and installing casing, comprising:
 (a) making up a casing string;   (b) securing to a drill pipe string a bottom hole assembly (BHA) having an earth boring bit and a fluid diverter, locking the drill pipe string to the casing string for rotation therewith and placing the fluid diverter between a passage of the drill pipe string and the interior of the casing string;   (c) rotating the bit to drill the well and pumping drilling fluid down the passage of the drill pipe string while the fluid diverter is in a drilling mode position, which causes the drilling fluid to flow out the drill bit;   (d) at a total depth for the casing string, moving the fluid diverter to a cementing position and pumping cement down the drill pipe, which flows out the chill pipe string above the drill bit and up a easing string annulus surrounding the casing string; and   (e) retrieving the BHA from the casing string after the cement has been dispensed.   
     
     
         2 . The method according to  claim 1 , further comprising:
 in step (a) mounting a packer in the casing string; and   after dispensing the cement in step (d) and before step (e), moving the flow diverter to a packer set position and pumping fluid down the drill string to set the packer and seal the casing string annulus to prevent cement in the casing string annulus from flowing downward.   
     
     
         3 . The method according to  claim 2 , wherein moving the fluid diverter to the packer set position comprises conveying a sealing member into the drill pipe string passage, which lands in the fluid diverter to block flow along a path of the cement and directs downward flow in the drill pipe string passage to the packer to set the packer. 
     
     
         4 . The method according to  claim 1 , wherein step (b) comprises providing the BHA with a mud motor, and step (c) comprises rotating the drill bit with the mud motor, reacting torque caused by the mud motor to the casing string, and causing the reacting torque to rotate the casing string in reverse to the rotation of the drill bit. 
     
     
         5 . The method according to  claim 1 , wherein step (b) comprises mounting an axial locking device to the drill pipe string and engaging the axial locking device with an upper end portion of the casing string to support the weight of the casing string. 
     
     
         6 . The method according to  claim 5 , wherein the axial locking device is mounted so that no torque is transmitted between the axial locking device and the casing string. 
     
     
         7 . The method according to  claim 1 , wherein moving the fluid diverter to the cementing position comprises conveying a sealing member down the drill pipe string passage, which lands in the fluid diverter to block downward flow in the drill pipe string passage and divert the downward flow to the interior of the casing string and at a lower end of the casing string, back up the casing annulus. 
     
     
         8 . The method according to  claim 1 , wherein step (c) comprises returning a portion of the drilling fluid after exiting the drill bit up a drill pipe string annulus between the drill pipe string and the casing string and returning another portion of the drilling fluid up the casing string annulus. 
     
     
         9 . The method according to  claim 8 , wherein step (d) comprises blocking any upward flow of fluid in the drill pipe string annulus above the fluid diverter. 
     
     
         10 . The method according to  claim 1 , wherein step (e) further comprises:
 after releasing the drill pipe string from the casing string and before retrieving the drill pipe string, pumping fluid down the drill pipe string and out the fluid diverter into an interior of the casing string to clean the BHA.   
     
     
         11 . A method of drilling a well and installing casing, comprising:
 (a) making up a casing string with a lower profile sub and a packer in a lower portion of the casing string;   (b) securing to a drill pipe string a bottom hole assembly (BHA) having an earth boring bit and a fluid diverter and installing the drill pipe string within the casing string;   (c) rotating the bit to drill the well while pumping drilling fluid down the passage of the drill pipe string while the fluid diverter is in a drilling mode position, which causes the drilling fluid to flow out the drill bit;   (d) at a total depth for the casing string, moving the fluid diverter to a cementing position and pumping cement down the drill pipe string passage, the fluid diverter blocking flow of the cement through the drill bit and directing the cement along a flow path out the drill pipe string and up a casing string annulus;   (e) after dispensing the cement, moving the flow diverter to a packer set position and pumping fluid down the drill pipe string passage and into the packer, which causes the packer to radially expand and seal the casing string annulus to prevent downward flow of cement in the casing annulus; then   (e) retrieving the bottom hole assembly from the casing string.   
     
     
         12 . The method according to  claim 11 , wherein:
 during step (c), some of the drilling fluid exiting the drill bit flows up an interior of the casing string past the fluid diverter to an upper end of the casing string; and   moving the fluid diverter to the cementing position in step (d) blocks the upward flow of any fluid in the interior of the casing string past the fluid diverter.   
     
     
         13 . The method according to  claim 11 , wherein moving the fluid diverter to the cementing position in step (d) comprises pumping down a first sealing member into the drill pipe string passage, which lands in the fluid diverter to block flow further down the drill pipe string passage and which directs the flow along the flow path of the cement. 
     
     
         14 . The method according to  claim 13 , wherein moving the fluid diverter to the packer set position in step (e) comprises pumping down a second sealing member into the drill pipe string passage, which lands in the fluid diverter to block further flow along the flow path of the cement and directs the flow to the packer. 
     
     
         15 . The method according to  claim 11 , wherein step (b) comprises providing the BHA with a mud motor, and step (c) comprises rotating the drill bit with the mud motor, reacting torque caused by the mud motor to the casing string, and causing the reacting torque to rotate the casing string in reverse to the drill bit. 
     
     
         16 . A method of drilling a well and installing casing, comprising:
 (a) making up a casing string;   (b) providing a bottom hole assembly (BHA) comprising a drill bit, a mud motor, and a locking unit above the mud motor;   (c) installing the BHA in the casing string and locking the locking unit to the casing string to transmit rotation;   (d) pumping drilling fluid through the BHA to drive the mud motor, causing the drill bit to rotate;   (e) reacting torque creating by the rotation of the drill bit through the locking unit to the casing string; and   (f) allowing the casing string to rotate in a reverse direction to the direction of rotation of the drill bit.   
     
     
         17 . The method according to  claim 16 , wherein step (f) further comprises applying a braking force to the rotation of the casing string to control the rotation of the casing string. 
     
     
         18 . The method according to  claim 16 , further comprising:
 connecting the BHA to a drill pipe string, causing the drill pipe string to rotate in unison with the casing string in step (f); and the method further comprises   connecting the drill pipe string to a top drive of a drilling rig, and step (f) comprises applying a braking force and controlling the rate of rotation of the drill pipe string with the top drive.   
     
     
         19 . The method according to  claim 16 , further comprising:
 connecting a casing gripper to a top drive of a drilling rig, and connecting an upper end of the casing string to the casing gripper; and   step (f) comprises applying a braking force and controlling the rate of rotation of the casing string with the top drive.   
     
     
         20 . A fluid diverter, comprising:
 a tubular mandrel with a threaded upper end for connection to a drill pipe string and a lower end for connection to a drill bit assembly, the mandrel having a mandrel passage for receiving fluid pumped down a drill pipe string passage;   a housing surrounding and carried by the mandrel;   a diverter port in the housing having an inlet in fluid communication with the mandrel passage and having an outlet exterior of the housing; and   a remotely actuated cementing valve that closes the diverter port while the fluid diverter is in a drilling mode and opens the diverter port while the fluid diverter valve is in a cementing mode.   
     
     
         21 . The apparatus according to  claim 20 , further comprising:
 a seal assembly mounted to the housing and extending radially therefrom for sealing engagement with an inner diameter of the casing string;   a bypass port in the seal assembly and extending from a lower to an upper side of the seal assembly; and   a remotely actuated bypass valve that opens the bypass port while the fluid diverter is in the drilling mode and closes the bypass port while the fluid diverter is in the cementing mode.   
     
     
         22 . The fluid diverter according to  claim 20 , further comprising:
 a packer adapted to be connected into the casing string;   a packer set port extending through the mandrel and the housing into fluid communication with the packer; and   a remotely actuated packer set valve that is closes the packer set port while the fluid diverter is in the drilling and cementing modes and opens the packer set port while in the packer set mode.