Measuring load on a drilling derrick during operations

Abstract

An elongatable beam extends between two points on the derrick. The elongatable beam is configured to produce a strain stream responsive to a change in a length of the elongatable beam. The length of the elongatable beam is configured to change responsive to flexing of the derrick due to a derrick load. A controller is operatively coupled to the elongatable beam. The controller configured to receive the strain stream from the elongatable beam and determine a derrick load responsive to the received strain stream.

What is claimed is: 
     
         1 . A derrick comprising:
 an elongatable beam extending between two points on the derrick, the elongatable beam configured to produce a strain stream responsive to a change in a length of the elongatable beam, the length of the elongatable beam configured to change responsive to flexing of the derrick due to a derrick load; and   a controller operatively coupled to the elongatable beam, the controller configured to:
 receive the strain stream from the elongatable beam; and 
 determine a derrick load responsive to the received strain stream. 
   
     
     
         2 . The derrick of  claim 1 , wherein the elongatable beam is anchored to each of the two points. 
     
     
         3 . The derrick of  claim 1 , wherein the controller is further configured to:
 determine that the derrick load has exceeded a predetermined threshold; and   cease operations of the derrick responsive to determining that the derrick load has exceeded the predetermined threshold.   
     
     
         4 . The derrick of  claim 3 , wherein the predetermined threshold is 85% of a rated load capacity of the derrick. 
     
     
         5 . The derrick of  claim 4 , further comprising a draw-works system coupled to the controller, the draw-works system comprising a cable and a winch, the cable being supported by the derrick, the draw-works system configured to adjust a load on items supported by the derrick, the controller further configured to:
 cease operations by shutting down the draw-works system.   
     
     
         6 . The derrick of  claim 1 , wherein the elongatable beam comprises a strain gauge, magnetic sensor, optical sensor, or fiber optic sensor. 
     
     
         7 . The derrick of  claim 1 , wherein the derrick extends vertically in-line with a wellbore, wherein the elongatable beam is arranged as a transverse member of the derrick. 
     
     
         8 . The derrick of  claim 1 , wherein the elongatable beam is a load-bearing member. 
     
     
         9 . The derrick of  claim 1 , wherein the elongatable beam is a first elongatable beam, the strain stream is a first strain stream, and the derrick load is a first derrick load, the derrick further comprising a second elongatable beam extending between two points on the derrick, the second elongatable beam configured to produce a second strain stream responsive to a length of the second elongatable beam, the controller further configured to:
 receive the second strain stream; and   determine a second derrick load responsive to the received second strain stream.   
     
     
         10 . The derrick of  claim 9 , wherein the controller is further configured to:
 compare the first derrick load and the second derrick load;   determine that the first derrick load and the second derrick load differ by a predetermined amount; and   produce a warning responsive to determining the first derrick load and the second derrick load differ by the predetermined amount.   
     
     
         11 . The derrick of  claim 10 , wherein the predetermined amount is substantially 5%. 
     
     
         12 . The derrick of  claim 9 , wherein the first elongatable beam and the second elongatable beam comprise different base technologies. 
     
     
         13 . A method comprising:
 changing a length of an elongatable beam of a derrick responsive to a load being received by a derrick, the elongatable beam extending between two points on the derrick;   measuring a change in length of the elongatable beam; and   determining a magnitude of the load responsive to measuring the change in length of the elongatable beam.   
     
     
         14 . The method of  claim 13 , further comprising:
 determining that a magnitude of the load exceeds a specified threshold; and   ceasing operations involving the derrick responsive to determining that a magnitude of the load exceeds a specified threshold.   
     
     
         15 . The method of  claim 14 , wherein ceasing operations comprises shutting down a draw-works system. 
     
     
         16 . The method of  claim 14 , wherein the specified threshold is 25% of a rated load capacity of the derrick. 
     
     
         17 . A drilling rig comprising:
 a derrick;   an elongatable beam extending between and anchored to two fixed points on the derrick, the elongatable beam configured to produce a strain stream responsive to a length of the elongatable beam;   a draw-works system configured to adjust a load on items supported by the derrick; and   a controller configured to:
 receive a strain stream from the elongatable beam; and 
 determine a load responsive to the received strain stream. 
   
     
     
         18 . The drilling rig of  claim 17 , the controller is further configured to:
 determine that the load has exceeded a predetermined threshold; and   cease operations of the draw-works system responsive to determining that the load has exceeded the predetermined threshold.   
     
     
         19 . The drilling rig of  claim 18 , wherein the predetermined threshold is 25% of a maximum load of the derrick according to finite element analysis of the derrick. 
     
     
         20 . The drilling rig of  claim 17 , wherein the elongatable beam comprises a strain gauge, magnetic sensor, optical sensor, or fiber optic sensor. 
     
     
         21 . The drilling rig of  claim 17 , wherein the elongatable beam is arranged as a transverse member of the derrick. 
     
     
         22 . The drilling rig of  claim 17 , wherein the elongatable beam is a load-bearing member.