Downhole caliper system and method

Abstract

A system includes a tool string and a caliper assembly. The caliper assembly includes one or more first calipers rotably coupled to the tool string. The one or more first calipers are circumferentially arrayed about a longitudinal central axis of the tool string. The caliper assembly also includes one or more second calipers rotably coupled to the tool string. The one or more second calipers are circumferentially arrayed about the longitudinal central axis. The caliper assembly also includes a drive element disposed within the tool string and slidably coupled to the tool string. The one or more first calipers extend from the tool string in response to the drive element moving to a first position. The one or more second calipers extend from the tool string in response to the drive element moving to a second position.

1 . A system, comprising:
 a tool string; and   a caliper assembly, comprising:
 one or more first calipers rotably coupled to the tool string, wherein the one or more first calipers are circumferentially arrayed about a longitudinal central axis of the tool string; 
 one or more second calipers rotably coupled to the tool string, wherein the one or more second calipers are circumferentially arrayed about the longitudinal central axis; and 
 a drive element disposed within the tool string and slidably coupled to the tool string; 
   wherein the one or more first calipers are configured to extend from the tool string in response to the drive element moving to a first position;   wherein the one or more second calipers are configured to extend from the tool string in response to the drive element moving to a second position.   
     
     
         2 . The system of  claim 1 , wherein the one or more second calipers are positioned in a downhole direction from the one or more first calipers. 
     
     
         3 . The system of  claim 2 , wherein the drive element is configured to slide along a longitudinal direction of the tool string. 
     
     
         4 . The system of  claim 3 , wherein the one or more second calipers are configured to retract into the tool string in response to the drive element moving to the first position, and the one or more first calipers are configured to retract into the tool string in response to the drive element moving to the second position. 
     
     
         5 . The system of  claim 4 , wherein the one or more first calipers are configured to rotate relative to the tool string in a first direction of rotation, the one or more second calipers are configured to rotate relative to the tool string in a second direction of rotation, and the first direction of rotation is opposite to the second direction of rotation. 
     
     
         6 . The system of  claim 4 , wherein the one or more first calipers are configured to retract into the tool string in response to the drive element moving to a third position, and the one or more second calipers are configured to concurrently retract into the tool string in response to the drive element moving to the third position. 
     
     
         7 . The system of  claim 4 , wherein the one or more first calipers are configured to be extended from the tool string and the one or more second calipers are configured to concurrently be retracted into the tool string and/or the one or more second calipers are configured to be extended from the tool string and the one or more first calipers are configured to concurrently be retracted into the tool string. 
     
     
         8 . The system of  claim 1 , wherein the one or more first calipers comprise one or more hook portions configured to contact the drive element. 
     
     
         9 . The system of  claim 8 , wherein the drive element comprises a longitudinal recess formed into an outer surface of the drive element. 
     
     
         10 . The system of  claim 9 , wherein the one or more first calipers comprise one or more spring portions configured to contact the tool string, wherein the one or more spring portions are configured to extend the one or more first calipers from the tool spring in response to the one or more hook portions moving into the longitudinal recess. 
     
     
         11 . A system, comprising:
 a tool string;   a caliper assembly, comprising:
 one or more first calipers rotably coupled to the tool string, wherein the one or more first calipers are circumferentially arrayed about a longitudinal central axis of the tool string; 
 one or more second calipers rotably coupled to the tool string, wherein the one or more second calipers are circumferentially arrayed about the longitudinal central axis; and 
 a drive element disposed within the tool string and slidably coupled to the tool string; and 
   a controller having a processor, wherein the controller is configured to:
 receive a first signal indicative of a first distance of a first extension of the one or more first calipers; and 
 determine an estimated first distance of the first extension of the one or more first calipers based on the first signal; 
   wherein the one or more first calipers are configured to extend from the tool string in response to the drive element moving to a first position;   wherein the one or more second calipers are configured to extend from the tool string in response to the drive element moving to a second position.   
     
     
         12 . The system of  claim 11 , wherein the one or more second calipers are positioned in a downhole direction from the one or more first calipers. 
     
     
         13 . The system of  claim 12 , wherein the drive element is configured to slide along a longitudinal direction of the tool string. 
     
     
         14 . The system of  claim 13 , wherein the controller is configured to:
 receive a second signal indicative of a second distance of a second extension of the one or more second calipers; and   determine an estimated second distance of the second extension of the one or more second calipers based on the second signal.   
     
     
         15 . The system of  claim 14 , comprising:
 a plunger coupled to:
 a first caliper of the one or more first calipers; and 
 a second caliper of the one or more second calipers; and 
   a sensor configured to determine a longitudinal position of the plunger relative to a radial axis disposed between the first caliper and the second caliper.   
     
     
         16 . The system of  claim 15 , wherein the first caliper is configured to pull an end portion of the plunger in an uphole direction relative to the radial axis in response to the first extension of the first caliper, and the second caliper is configured to pull the end portion of the plunger in the downhole direction relative to the radial axis in response to the second extension of the second caliper. 
     
     
         17 . The system of  claim 16 , wherein the controller is configured to:
 receive a third signal indicative of the longitudinal position of the plunger; and   determine the first distance of the first extension of the first caliper, the second distance of the second extension of the second caliper, or a combination thereof based on the received third signal.   
     
     
         18 . The system of  claim 17 , wherein the controller is configured to:
 determine whether the longitudinal position is uphole from the radial axis or downhole from the radial axis;   determine the first distance of the first extension of the first caliper in response to the longitudinal position being uphole from the radial axis; and   determine the second distance of the second extension of the second caliper in response to the longitudinal position being downhole from the radial axis.   
     
     
         19 . A method, comprising:
 placing a tool string in a wellbore of a well;   extending a plurality of first calipers from the tool string;   lowering the tool string through the wellbore while the plurality of first calipers is extended;   retracting the plurality of first calipers into the tool string;   extending a plurality of second calipers from the tool string; and   raising the tool string through the wellbore while the plurality of second calipers is extended.   
     
     
         20 . The method of  claim 19 , comprising:
 receiving, via one or more processors, a signal indicative of a longitudinal position of a plunger disposed inside the tool string; and   in response to receiving the signal:
 determining, via the one or more processors, a first distance of a first extension of a first caliper of the plurality of first calipers based on the signal; 
 determining, via the one or more processors, a second distance of a second extension of a second caliper of the plurality of second calipers based on the signal; 
 or a combination thereof.