One Trip Bottom Hole Assembly and Method for Milling Casing and Directionally Drilling a Lateral Wellbore

Abstract

A bottom hole assembly and method for cutting a window in a cased, oil and gas wellbore and directionally drilling a lateral wellbore through the window without tripping the bottom hole assembly between milling the window and commencing directional drilling of the lateral wellbore.

What is claimed is: 
     
         1 . A method of drilling a lateral wellbore by sidetracking from an existing, cased wellbore, comprising the steps of:
 connecting a bottom hole assembly (BHA) to a drill string, the bottom hole assembly comprising:   a motor coupled with the drill string, the motor comprising a power section and output section, wherein the motor is adapted to allow locking of the motor to prevent rotation of the output section relative to the motor and unlocking the motor to allow for rotation;   a cutting head coupled with the output section of the motor;   one or more mills for enlarging an opening formed by the cutting head; and   a whipstock assembly releasably connected to the cutting head;   wherein the BHA is adapted for remotely changing while downhole a deviation of an axis of rotation of the output section of the motor with respect to a central axis of the drill string from a first angle for cutting and milling a window in a casing string to a second, non-zero-degree angle for directional drilling;   lowering the BHA on the drill string into a previously cased wellbore;   once the BHA is at a depth for a planned window in a casing string in the wellbore, rotating the drill string with the motor locked, while the deviation of the axis of rotation of the output section is set at zero degrees, to orient the whipstock;   anchoring the whipstock in the wellbore;   releasing the whipstock from the BHA;   lowering the BHA toward the whipstock to cause the cutting head to deflect toward the casing string;   rotating the cutting head to cut an opening in the casing string and to form a rat hole;   rotating the at least one mill to enlarge the opening;   without raising the BHA to the surface, changing the deviation of the axis of rotation of the output section of the motor to the second, non-zero-degree angle for directional drilling; and   directionally drilling the wellbore with the motor unlocked and the axis of rotation of the output section of the motor in the second, non-zero-degree angle.   
     
     
         2 . The method of  claim 1 , further comprising:
 orienting a cutting face of the cutting head along a planned trajectory by rotating the drill string from the surface; and   powering the motor with the motor unlocked to rotate the cutting assembly.   
     
     
         3 . The method of  claim 1  wherein the deviation of the axis of rotation of the output section of the motor is set to the first angle prior to lowering the BHA into the wellbore. 
     
     
         4 . The method of  claim 1  wherein the motor is locked prior to lowering the BHA into the wellbore. 
     
     
         5 . The method of  claim 4  wherein the motor is unlocked to begin direction drilling of the wellbore. 
     
     
         6 . The method of  claim 1  wherein during at least a portion of a period in which the cutting head is cutting the opening or the at least one mill is enlarging the opening the motor is locked, and the cutting head is rotated by rotating the drill string from the surface. 
     
     
         7 . The method of  claim 1 , wherein the motor is unlocked and powered to rotate the cutting head to cut the opening. 
     
     
         8 . The method of  claim 1 , wherein the motor is locked against rotation during milling and the cutting head is rotated by rotating the drill string. 
     
     
         9 . The method of  claim 1 , wherein the BHA comprises a means for changing the deviation of the axis of rotation of the output section of the motor to the second, non-zero angle for directional drilling. 
     
     
         10 . The method of  claim 1  wherein the BHA comprises at least one of an adjustable sub coupling the motor to the drill string and a motor with an adjustable lower housing, the adjustable sub being configured to change downhole the deviation of the output section of the motor from the first angle to the second, non-zero-degree angle, and the adjustable lower housing being configured to change downhole the deviation of the output section of the motor from the first angle to the second, non-zero-degree angle. 
     
     
         11 . The method of  claim 9 , wherein changing the deviation of the axis of rotation of the output section of the motor to the second, non-zero-degree angle for directional drilling comprises pulling, pushing or rotating the drill string from the surface. 
     
     
         12 . The method of  claim 9 , wherein changing the deviation of the axis of rotation of the output section of the motor to the second, non-zero-degree angle for directional drilling comprises pumping drilling fluid down the drill string. 
     
     
         13 . The method of  claim 9 , wherein changing the deviation of the axis of rotation of the output section of the motor to the second, non-zero-degree angle for directional drilling comprises actuating a setting tool in the BHA. 
     
     
         14 . The method of  claim 1  wherein at least one of the one or more mills is coupled with the output section of the motor. 
     
     
         15 . The method of  claim 1  wherein at least one of the one or more mills is coupled with the power section of the motor to rotate with the power section of the motor. 
     
     
         16 . A bottom hole assembly (BHA) for sidetracking from an existing wellbore, the bottom hole assembly comprising:
 a motor coupled with a drill string, the motor comprising a power section and a lockable output section adapted for unlocking downhole;   a cutting head coupled with the output section of the motor;   one or more mills for enlarging an opening formed by the cutting head; and   a whipstock assembly releasably coupled to the cutting head;   wherein the BHA is adapted for selectively changing while downhole a deviation of an axis of rotation of the output section of the motor with respect to a central axis of the drill string from a first angle for cutting an opening for a window to a second, non-zero-degree angle for directional drilling;   the BHA further comprising at least one of an adjustable sub coupling the motor to the drill string and a motor with an adjustable lower housing, the adjustable sub being configured to change downhole the deviation of the output section of the motor from the first angle to the second, non-zero degree angle, and the adjustable lower housing being configured to change downhole the deviation of the output section of the motor from zero degrees to a non-zero-degree angle.   
     
     
         17 . The bottom hole assembly of  claim 16  wherein the BHA changes the deviation of the axis of rotation of the output section of the motor to the second, non-zero-degree angle for directional drilling in response to movement of the drill string to which it is attached, the movement comprising one or more of pulling, pushing or rotating the drill string. 
     
     
         18 . The bottom hole assembly of  claim 16  wherein the BHA changes the deviation of the axis of rotation of the output section of the motor to the second, non-zero-degree angle for directional drilling in response to drilling fluid being pumped through the BHA. 
     
     
         19 . The bottom hole assembly of  claim 16  wherein the BHA changes the deviation of the axis of rotation of the output section of the motor to the second, non-zero-degree angle for directional drilling in response to actuation of a setting tool in the BHA.