Automated two-hole drilling using ranging

Abstract

Methods and systems are provided for drilling a secondary wellbore relative to a target wellbore, which involve drilling the secondary wellbore with a bottomhole assembly (BHA) that extends from a drill string. The BHA includes a magnetic field detector, a steering component, a drill bit, and at least one processor. The magnetic field detector is configured to detect a time- varying magnetic field generated from a rotating magnetic source of a drilling tool disposed in the target wellbore. The at least one processor is configured to i) use data output by the magnetic field detector to continually determine distance and direction or azimuth of the magnetic source relative to the BHA while drilling, and ii) use the distance and direction or azimuth of the magnetic source relative to the BHA while drilling to adjust the steering of the drilling performed by the BHA as controlled by the steering component of the BHA. The operations of the least one processor can be configured to adjust steering of the drilling of the BHA in order to maintain a set distance and direction or azimuth relative to the target wellbore, autonomously without surface input or interference, whilst drilling with the BHA.

We claim: 
     
         1 . A method for drilling a secondary wellbore relative to a target wellbore, the method comprising: 
 drilling the secondary wellbore with a bottomhole assembly (BHA) that extends from a drill string, wherein the BHA includes a magnetic field detector, a steering component, a drill bit, and at least one processor;   configuring the magnetic field detector to detect a time-varying magnetic field generated from a rotating magnetic source of a drilling tool disposed in the target wellbore; and   configuring the at least one processor to i) use data output by the magnetic field detector to continually determine distance and direction or azimuth of the magnetic source relative to the BHA while drilling the secondary wellbore, and ii) use the distance and direction or azimuth of the magnetic source relative to the BHA while drilling the secondary wellbore to adjust the steering of the drilling performed by the BHA as controlled by the steering component of the BHA.   
     
     
         2 . The method of  claim 1 , further comprising: 
 configuring the at least one processor to adjust steering of the drilling of the BHA in order to maintain a set distance and direction or azimuth relative to the target wellbore, autonomously without surface input or interference, whilst drilling the secondary wellbore with the BHA.   
     
     
         3 . The method of  claim 2 , wherein: 
 the adjustment of the steering of the drilling of the BHA is part of a closed-loop drilling mode carried out under the control of the at least one processor.   
     
     
         4 . The method of  claim 1 , wherein: 
 the magnetic field detector comprises a plurality of magnetometers.   
     
     
         5 . The method of  claim 1 , wherein: 
 the time-varying magnetic field generated from the rotating magnetic source in the target wellbore comprises a time-varying sinusoidal magnetic field.   
     
     
         6 . The method of  claim 1 , wherein: 
 the rotating magnetic source in the target wellbore is configured to generate the time-varying magnetic field while drilling the target wellbore.   
     
     
         7 . The method of  claim 5 , wherein: 
 the at least one processor is configured to control steering of the drilling performed by the BHA such that the trajectory or path of the secondary wellbore follows the trajectory or path of the target wellbore.   
     
     
         8 . The method of  claim 1 , wherein: 
 the steering component comprises a rotary steerable system or part thereof.   
     
     
         9 . A downhole drilling system for drilling a secondary wellbore relative to a target wellbore, the downhole drilling system comprising: 
 a bottomhole assembly (BHA) configured to extend from a drill string, wherein the BHA includes a magnetic field detector, a steering component, a drill bit, and at least one processor;   wherein the magnetic field detector is configured to detect a time-varying magnetic field generated from a rotating magnetic source of a drilling tool disposed in the target wellbore; and   the at least one processor is configured to i) use data output by the magnetic field detector to continually determine distance and direction or azimuth of the magnetic source relative to the BHA while drilling the secondary wellbore, and ii) use the distance and direction or azimuth of the magnetic source relative to the BHA while drilling the secondary wellbore to adjust the steering of the drilling performed by the BHA as controlled by the steering component of the BHA.   
     
     
         10 . The downhole drilling system of  claim 9 , wherein: 
 the at least one processor is configured to adjust the steering of the drilling of the BHA in order to maintain a set distance and direction or azimuth relative to the target wellbore, autonomously without surface input or interference, whilst drilling the secondary wellbore with the BHA.   
     
     
         11 . The downhole drilling system of  claim 10 , wherein: 
 the adjustment of the steering of the drilling of the BHA is part of a closed-loop drilling mode carried out under the control of the at least one processor.   
     
     
         12 . The downhole drilling system of  claim 9 , wherein: 
 the magnetic field detector comprises a plurality of magnetometers.   
     
     
         13 . The downhole drilling system of  claim 9 , wherein: 
 the time-varying magnetic field generated from the rotating magnetic source in the target wellbore comprises a time-varying sinusoidal magnetic field.   
     
     
         14 . The downhole drilling system of  claim 9 , wherein: 
 the rotating magnetic source in the target wellbore is configured to generate the time-varying magnetic field while drilling the target wellbore.   
     
     
         15 . The downhole drilling system of  claim 14 , wherein: 
 the steering of the drilling performed by the BHA is controlled such that the trajectory or path of the secondary wellbore follows the trajectory or path of the target wellbore.   
     
     
         16 . The downhole drilling system of  claim 9 , wherein: 
 the steering component comprises a rotary steerable system or part thereof.   
     
     
         17 . A downhole drilling system for drilling a secondary wellbore relative to a target wellbore, the system comprising: 
 a first bottomhole assembly (BHA) configured to extend from a first drill string, wherein the first BHA includes a drilling tool for drilling the target wellbore and a rotatable magnetic source disposed in the target wellbore; and   a second BHA configured to extend from a second drill string, wherein the second BHA includes magnetic field detector, a steering component, a drill bit, and at least one processor;   
       
         wherein the magnetic field detector is configured to detect a time-varying magnetic field generated from rotation of the magnetic source of the drilling tool disposed in the target wellbore; and 
       
       
         wherein the at least one processor is configured to i) use data output by the magnetic field detector to continually determine distance and direction or azimuth of the magnetic source relative to the second BHA while drilling the secondary wellbore, and ii) use the distance and direction or azimuth of the magnetic source relative to the second BHA while drilling the secondary wellbore to adjust the steering of the drilling performed by the second BHA as controlled by the steering component of the second BHA. 
       
     
     
         18 . The downhole drilling system of  claim 17 , wherein: 
 the at least one processor is configured to adjust steering of the drilling of the second BHA in order to maintain a set distance and direction or azimuth relative to the target wellbore, autonomously without surface input or interference, whilst drilling the secondary wellbore with the second BHA.   
     
     
         19 . The downhole drilling system of  claim 18 , wherein: 
 the adjustment of the steering of the drilling of the BHA is part of a closed-loop drilling mode carried out under the control of the at least one processor.   
     
     
         20 . The downhole drilling system of  claim 17 , wherein: 
 the rotating magnetic source in the target wellbore is configured to generate the time-varying magnetic field while drilling the target wellbore.   
     
     
         21 . The downhole drilling system of  claim 20 , wherein: 
 the steering of the drilling performed by the second BHA is controlled such that the trajectory or path of the secondary wellbore follows the trajectory or path of the target wellbore.