Methods, systems, and computer-readable media for performing automated drilling of a wellbore

Abstract

During drilling of a wellbore, in a predicting state, a drilling parameter is monitored and, based on the monitored drilling parameter, it is determined that the drilling parameter is likely to exceed a drilling parameter setpoint associated with the drilling parameter. In a mitigating state, in response to determining that the drilling parameter is likely to exceed the drilling parameter setpoint, a rate of penetration setpoint is reduced so as to mitigate a likelihood of the drilling parameter exceeding the drilling parameter setpoint. In addition, during the drilling, drilling parameter data is received. A controller is used to generate, based on the drilling parameter data, one or more drilling parameter setpoint recommendations. At least one drilling parameter setpoint recommendation is selected. The selected drilling parameter setpoint is provided to an automated drilling unit that is separate from the controller.

1 . A method of performing automated drilling of a wellbore, comprising, during drilling of the wellbore:
 in a predicting state:
 monitoring a drilling parameter; and 
 determining, based on the monitored drilling parameter, that the drilling parameter is likely to exceed a drilling parameter setpoint associated with the drilling parameter; 
   in a mitigating state:
 in response to determining that the drilling parameter is likely to exceed the drilling parameter setpoint, reducing a rate of penetration (ROP) setpoint so as to mitigate a likelihood of the drilling parameter exceeding the drilling parameter setpoint; and 
 drilling the wellbore according to the reduced ROP setpoint. 
   
     
     
         2 . The method of  claim 1 , wherein reducing the ROP setpoint comprises continuously reducing the ROP setpoint over a time window. 
     
     
         3 . The method of  claim 1 , wherein reducing the ROP setpoint comprises reducing the ROP setpoint by a step change. 
     
     
         4 . The method of  claim 1 , wherein determining that the drilling parameter is likely to exceed the drilling parameter setpoint comprises determining one or more of the following conditions:
 a current reading of the drilling parameter is less than the drilling parameter setpoint minus a threshold;   a current reading of the drilling parameter is greater than a next most recent reading of the drilling parameter;   a slope of a linear regression calculated based on a set of drilling parameter readings, including the current reading of the drilling parameter and one or more older readings of the drilling parameter, is positive; and   a current reading of the drilling parameter and each of one or more previous readings of the drilling parameter are greater than the threshold.   
     
     
         5 . The method of  claim 4 , wherein determining that the drilling parameter is likely to exceed the drilling parameter setpoint comprises determining each of the above conditions. 
     
     
         6 . The method of  claim 1 , wherein, after drilling the wellbore according to the reduced ROP setpoint, the method returns to the predicting state if any of the following conditions is true:
 a current reading of the drilling parameter is less than the drilling parameter setpoint minus a threshold;   a current reading of the drilling parameter is greater than the drilling parameter setpoint;   a slope of a linear regression calculated based on a set of drilling parameter readings, including the current reading of the drilling parameter and one or more older readings of the drilling parameter, is negative; and   an elapsed time since the method has been in the mitigation state has increased above a threshold.   
     
     
         7 . The method of  claim 1 , wherein reducing the ROP setpoint comprises reducing the ROP setpoint by an amount based on one or more of:
 a rate of change of ROP;   a rate of change of a weight on bit (WOB);   a rate of change of torque; and   a rate of change of differential pressure.   
     
     
         8 . The method of  claim 1 , wherein the drilling parameter is differential pressure, and wherein the drilling parameter setpoint is a differential pressure setpoint. 
     
     
         9 . The method of  claim 8 , wherein the amount by which the ROP setpoint is reduced is based on a score that is equal to:
 [(rop.dop.dp.slope.weight*dpSlopeScore)+(rop.dop.wob.slope.weight*wobSlopeScore)+(rop.dop.tq.slope.weight*tqSlopeScore)+(rop.dop.dp.prox.weight*dpProxScore)+(rop.dop.rop.slope.weight*ropSlopeScore)]/TotalParameters, wherein:
 rop.dop.dp.slope.weight, rop.dop.wob.slope.weight, rop.dop.tq.slope.weight, rop.dop.dp.prox.weight, and rop.dop.rop.slope.weight are constants; 
 dpSlopeScore is the rate of change of the differential pressure; 
 wobSlopeScore is the rate of change of a WOB; 
 tqSlopeScore is the rate of change of a torque; 
 ropSlopeScore is the rate of change of ROP; 
 dpProxScore is based on the differential pressure and the differential pressure setpoint; and 
 TotalParameters is rop.dop.dp.prox.weight+rop.dop.dp.slope.weight+rop.dop.tq.slope.weight+rop.dop.rop.slope.weight+rop.dop.wob.slope.weight. 
   
     
     
         10 . The method of  claim 9 , wherein dpProxScore=[Dp−(Dpsp−rop.dop.dp.prox.thresh)]/rop.dop.dp.prox.thresh, wherein:
 Dp is the differential pressure; 
 Dpsp is the differential pressure setpoint; and 
 rop.dop.dp.prox.thresh is a threshold. 
 
     
     
         11 . The method of  claim 9 , wherein the amount by which the ROP setpoint is reduced is equal to:
 z*scaling factor, wherein:
 z is the score; and 
 scaling factor is based on ROP and the ROP setpoint. 
   
     
     
         12 . A system for performing automated drilling of a wellbore, the system comprising:
 a height control apparatus configured to adjust a height of a drill string comprising a drill bit used to drill the wellbore;   a height sensor for monitoring a height of the drill string;   a rotational drive unit comprising a rotational drive unit controller and a rotation rate sensor for monitoring a rotation rate of the drill bit;   a depth sensor for monitoring a depth of the drill bit;   a hookload sensor for measuring a weight applied to the drill bit;   a pressure sensor for monitoring a differential pressure;   a drilling controller communicatively coupled to the rotational drive unit controller, the rotation rate sensor, the height control apparatus, the height sensor, the depth sensor, the hookload sensor, and the pressure sensor, and the drilling controller being configured to perform a method comprising:
 in a predicting state:
 monitoring one or more drilling parameters; and 
 determining, based on the monitored one or more drilling parameters, that at least one of the one or more drilling parameters is likely to exceed at least one drilling parameter setpoint associated with the at least one drilling parameter; 
 
 in a mitigating state:
 in response to determining that the at least one drilling parameter is likely to exceed the at least one drilling parameter setpoint, reducing a rate of penetration (ROP) setpoint so as to mitigate a likelihood of the at least one drilling parameter exceeding the at least one drilling parameter setpoint; and 
 
 drilling the wellbore according to the reduced ROP setpoint. 
   
     
     
         13 . The system of  claim 12 , wherein determining that the drilling parameter is likely to exceed the drilling parameter setpoint comprises determining one or more of the following conditions:
 a current reading of the drilling parameter is less than the drilling parameter setpoint minus a threshold;   a current reading of the drilling parameter is greater than a next most recent reading of the drilling parameter;   a slope of a linear regression calculated based on a set of drilling parameter readings, including the current reading of the drilling parameter and one or more older readings of the drilling parameter, is positive; and   a current reading of the drilling parameter and each of one or more previous readings of the drilling parameter are greater than the threshold.   
     
     
         14 . The system of  claim 13 , wherein determining that the drilling parameter is likely to exceed the drilling parameter setpoint comprises determining each of the above conditions. 
     
     
         15 . The system of  claim 12 , wherein, after drilling the wellbore according to the reduced ROP setpoint, the drilling controller is configured to return the method to the predicting state if any of the following conditions is true:
 a current reading of the drilling parameter is less than the drilling parameter setpoint minus a threshold;   a current reading of the drilling parameter is greater than the drilling parameter setpoint;   a slope of a linear regression calculated based on a set of drilling parameter readings, including the current reading of the drilling parameter and one or more older readings of the drilling parameter, is negative; and   an elapsed time since the method has been in the mitigation state has increased above a threshold.   
     
     
         16 . The system of  claim 12 , wherein reducing the ROP setpoint comprises reducing the ROP setpoint by an amount based on one or more of:
 a rate of change of ROP;   a rate of change of a weight on bit (WOB);   a rate of change of torque; and   a rate of change of differential pressure.   
     
     
         17 . The system of  claim 12 , wherein the drilling parameter is differential pressure, and wherein the drilling parameter setpoint is a differential pressure setpoint. 
     
     
         18 . The system of  claim 17 , wherein the amount by which the ROP setpoint is reduced is based on a score that is equal to:
 [(rop.dop.dp.slope.weight*dpSlopeScore)+(rop.dop.wob.slope.weight*wobSlopeScore)+(rop.dop.tq.slope.weight*tqSlopeScore)+(rop.dop.dp.prox.weight*dpProxScore)+(rop.dop.rop.slope.weight*ropSlopeScore)]/TotalParameters, wherein:
 rop.dop.dp.slope.weight, rop.dop.wob.slope.weight, rop.dop.tq.slope.weight, rop.dop.dp.prox.weight, and rop.dop.rop.slope.weight are constants; 
 dpSlopeScore is the rate of change of the differential pressure; 
 wobSlopeScore is the rate of change of a WOB; 
 tqSlopeScore is the rate of change of a torque; 
 ropSlopeScore is the rate of change of ROP; 
 dpProxScore is based on the differential pressure and the differential pressure setpoint; and 
 TotalParameters is rop.dop.dp.prox.weight+rop.dop.dp.slope.weight+rop.dop.tq.slope.weight+rop.dop.rop.slope.weight+rop.dop.wob.slope.weight. 
   
     
     
         19 . The system of  claim 18 , wherein the amount by which the ROP setpoint is reduced is equal to:
 z*scaling factor, wherein:
 z is the score; and 
 scaling factor is based on ROP and the ROP setpoint. 
   
     
     
         20 . A non-transitory computer-readable medium having stored thereon program code executable by a processor and configured, when executed, to cause the processor to perform a method of performing automated drilling of a wellbore using a drill bit, comprising:
 in a predicting state:
 monitoring one or more drilling parameters; and 
 determining, based on the monitored one or more drilling parameters, that the at least one of the one or more drilling parameters is likely to exceed at least one drilling parameter setpoint associated with the at least one drilling parameter; 
   in a mitigating state:
 in response to determining that the at least one drilling parameter is likely to exceed the at least one drilling parameter setpoint, reducing a rate of penetration (ROP) setpoint so as to mitigate a likelihood of the at least one drilling parameter exceeding the at least one drilling parameter setpoint; and 
 drilling the wellbore according to the reduced ROP setpoint.