Automated kick and loss detection

Abstract

A method for monitoring and controlling a mud flow system in a drilling rig includes measuring an active mud volume in an active mud pit and an inactive mud volume in an inactive mud pit, modeling a modeled active mud volume in the active mud pit, determining a mud volume balance by calculating a difference between the measurement of the active mud volume and the modeled active mud volume, detecting a transfer of mud from the inactive mud pit to the active mud pit based on a combination of a change in the measurement of the inactive mud volume in the inactive mud pit and a change in the mud volume balance, and detecting downhole gains and losses automatically based on the mud volume balance.

What is claimed is: 
     
         1 . A method for monitoring and controlling a mud flow system in a drilling rig, comprising:
 measuring an active mud volume in an active mud pit and an inactive mud volume in an inactive mud pit;   modeling a modeled active mud volume in the active mud pit;   determining a mud volume balance by calculating a difference between the measurement of the active mud volume and the modeled active mud volume;   detecting a transfer of mud from the inactive mud pit to the active mud pit based on a combination of a change in the measurement of the inactive mud volume in the inactive mud pit and a change in the mud volume balance; and   detecting downhole gains and losses automatically based on the mud volume balance.   
     
     
         2 . The method of  claim 1 , further comprising revising the mud volume balance to account for the transfer, in response to detecting the transfer. 
     
     
         3 . The method of  claim 1 , wherein modeling the modeled active mud volume comprises:
 determining a permeability loss coefficient during transient flow periods; and   determining a surface loss coefficient during steady-state periods,   wherein the modeled active mud volume is modeled based on a combination of the permeability loss coefficient and the surface loss coefficient.   
     
     
         4 . The method of  claim 3 , wherein the permeability loss coefficient is related to mud flow into or out of a subterranean formation, and wherein surface loss coefficient is related at least in part to mud flow out of a shaker of a drilling system. 
     
     
         5 . The method of  claim 3 , further comprising recalibrating the surface loss coefficient during a steady-state flow period after a first pump start and before a first pump stoppage, wherein the surface loss coefficient is not recalibrated after the first pump stoppage and before a second pump stoppage. 
     
     
         6 . The method of  claim 3 , further comprising recalibrating the permeability loss coefficient during a pump start, before reaching a steady-state flow period after the pump start. 
     
     
         7 . The method of  claim 1 , wherein detecting the transfer of mud comprises:
 determining that the inactive mud volume has changed by more than a threshold amount; and   in response to determining that the inactive mud volume has changed, determining that the mud volume balance has changed to compensate for the inactive mud volume changing.   
     
     
         8 . The method of  claim 7 , wherein detecting the transfer of mud further comprises determining that a mud volume in another inactive mud pit has not changed to compensate for the change in the inactive mud volume, wherein determining that the mud volume balance has changed to compensate for the inactive mud volume changing is also in response to determining that the mud volume in the other inactive mud pit has not changed to compensate. 
     
     
         9 . The method of  claim 1 , further comprising deactivating or refraining from activating a kick alarm in response to detecting the transfer of mud. 
     
     
         10 . The method of  claim 1 , further comprising pumping mud into a well using the mud flow system, wherein the mud is circulated through the active mud pit. 
     
     
         11 . A computing system, comprising:
 one or more processors; and   a memory system comprising one or more non-transitory computer-readable media storing instructions that, when executed by at least one of the one or more processors, cause the computing system to perform operations, the operations comprising:
 measuring an active mud volume in an active mud pit and an inactive mud volume in an inactive mud pit; 
 modeling a modeled active mud volume in the active mud pit; 
 determining a mud volume balance by calculating a difference between the measurement of the active mud volume and the modeled active mud volume; 
 detecting a transfer of mud from the inactive mud pit to the active mud pit based on a combination of a change in the measurement of the inactive mud volume in the inactive mud pit and a change in the mud volume balance; and 
 detecting downhole gains and losses automatically based on the mud volume balance. 
   
     
     
         12 . The computing system of  claim 11 , wherein the operations further comprise revising the mud volume balance to account for the transfer, in response to detecting the transfer. 
     
     
         13 . The computing system of  claim 11 , wherein modeling the modeled active mud volume comprises:
 determining a permeability loss coefficient during transient flow periods; and   determining a surface loss coefficient during steady-state periods,   wherein the modeled active mud volume is modeled based on a combination of the permeability loss coefficient and the surface loss coefficient.   
     
     
         14 . The computing system of  claim 13 , wherein the permeability loss coefficient is related to mud flow into or out of a subterranean formation, and wherein surface loss coefficient is related at least in part to mud flow out of a shaker of a drilling system. 
     
     
         15 . The computing system of  claim 13 , wherein the operations further comprise recalibrating the surface loss coefficient during a steady-state flow period after a first pump start and before a first pump stoppage, wherein the surface loss coefficient is not recalibrated after the first pump stoppage and before a second pump stoppage. 
     
     
         16 . The computing system of  claim 13 , wherein the operations further comprise recalibrating the permeability loss coefficient during a pump start, before reaching a steady-state flow period after the pump start. 
     
     
         17 . The computing system of  claim 11 , wherein detecting the transfer of mud comprises:
 determining that the inactive mud volume has changed by more than a threshold amount; and   in response to determining that the inactive mud volume has changed, determining that the mud volume balance has changed to compensate for the inactive mud volume changing.   
     
     
         18 . The computing system of  claim 17 , wherein detecting the transfer of mud further comprises determining that a mud volume in another inactive mud pit has not changed to compensate for the change in the inactive mud volume, wherein determining that the mud volume balance has changed to compensate for the inactive mud volume changing is also in response to determining that the mud volume in the other inactive mud pit has not changed to compensate. 
     
     
         19 . A computing system, comprising:
 one or more processors; and   a memory system comprising one or more non-transitory computer-readable media storing instructions that, when executed by at least one of the one or more processors, cause the computing system to perform operations, the operations comprising:
 measuring an active mud volume in an active mud pit and an inactive mud volume in an inactive mud pit; 
 modeling a modeled active mud volume in the active mud pit; 
 determining a mud volume balance by calculating a difference between the measurement of the active mud volume and the modeled active mud volume; 
 detecting a transfer of mud from the inactive mud pit to the active mud pit based on a combination of a change in the measurement of the inactive mud volume in the inactive mud pit and a change in the mud volume balance; and 
 detecting downhole gains and losses automatically based on the mud volume balance. 
   
     
     
         20 . The computing system of  claim 19 , wherein the operations further comprise revising the mud volume balance to account for the transfer, in response to detecting the transfer, and wherein modeling the modeled active mud volume comprises:
 determining a permeability loss coefficient during transient flow periods; and   determining a surface loss coefficient during steady-state periods,   wherein the modeled active mud volume is modeled based on a combination of the permeability loss coefficient and the surface loss coefficient.