Methods for determining mechanical specific energy for wellbore operations

Abstract

A method for determining mechanical specific energy for a wellbore operation (e.g., drilling), the method including: measuring power input to machines used in a wellbore and producing a value for input power; calculating mechanical specific power for the operation based on the value for the input power; a computer-readable media for performing a step or steps of the method; and a computing unit for reading and performing the step or steps. This abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims, 37 C.F.R. 1.72( b ).

1 . A method for determining mechanical specific energy for a wellbore operation, the method comprising:
 measuring power input to machines used in a wellbore operation and producing a value for input power,   calculating mechanical specific energy for the operation based on the value for the input power.   
     
     
         2 . The method of  claim 1  wherein the power input is electrical power and the value for input power is a value for electrical power. 
     
     
         3 . The method of  claim 1  wherein the power input is hydraulic power and the value for input power is a value for hydraulic power. 
     
     
         4 . The method of  claim 1  wherein the machines include a rotator for rotating tubulars used in the wellbore operation. 
     
     
         5 . The method of  claim 4  wherein the rotator is at least one of rotary table system, top drive system, and mud motor system. 
     
     
         6 . The method of  claim 1  wherein measuring the power input includes measuring power for a mud pump system and power for at least one rotator for rotating tubulars used in the wellbore operation. 
     
     
         7 . The method of  claim 6  wherein the at least one rotator is all rotators used for rotating tubulars used in the wellbore operation. 
     
     
         8 . The method of  claim 1  wherein the wellbore operation is a wellbore drilling operation using only either a rotary table system or a top drive system and Mechanical Specific Energy, MSE, is calculated according to the equation:
   MSE conventional =(3,380.7*KW rt/td )/( D   2 *ROP)   in which “KW” is input power measured in kilowatts; “D” is bit diameter area for the drill bit used; and “ROP” is rate of penetration of the drill bit through the formation.   
     
     
         9 . The method of  claim 1  wherein the wellbore operation is a wellbore drilling operation using a downhole mud motor to rotate a drill bit to drill a wellbore and Mechanical Specific Energy, MSE, is calculated according to the equations:
   Δ PumpKW =KW on     —     bottom −KW off     —     bottom        MSE conventional     —     DH =(3,380.7*Δ PumpKW )/( D   2 *ROP)   in which “KW” is input power measured in kilowatts; “D” is bit diameter area for the drill bit used; and “ROP” is rate of penetration of the drill bit through the formation, and “ΔPUMPKW” is the difference between kilowatts input to a mud pump system used in the wellbore drilling operation with the bit on-bottom (“KW on_bottom”), and off-bottom of the wellbore (“KW off_bottom).   
     
     
         10 . The method of  claim 1  wherein the wellbore operation is a wellbore drilling operation using a rotator for rotating tubulars and a downhole mud motor to rotate a drill bit, and Mechanical Specific Energy, MSE, is calculated according to the equation:
   MSE combined =(3,380.7*(KW rt/td +Δ PumpKW ))/( D   2 *ROP)   
       in which “KW” is input power measured in kilowatts; “D” is bit diameter area for the drill bit used; and “ROP” is rate of penetration of the drill bit through the formation, and “ΔPUMPKW” is the difference between kilowatts input to a mud pump system used in the wellbore drilling operation with the bit on-bottom (“KW on_bottom”), and off-bottom of the wellbore (“KW off_bottom). 
     
     
         11 . The method of  claim 1  wherein the wellbore operation is a wellbore drilling operation and a wellbore is being drilled with a downhole mud motor using an hydraulically powered mud pump system which inputs power to a formation being drilled via mud pumped through a drill bit being used to drill the wellbore, and Mechanical Specific Energy, MSE, is calculated according to the equation:
   MSE Total =(3,380.7*(KW rt/td +KW on     —     bottom ))/( D   2 *ROP)   in which “KW” is input power measured in kilowatts; “D” is bit diameter area for the drill bit used; and “ROP” is rate of penetration of the drill bit through the formation, and KW on bottom is power input to the downhole mud motor.   
     
     
         12 . The method of  claim 1  further comprising
 supply power to the machines with a rig power system.   
     
     
         13 . The method of  claim 1  wherein the wellbore operation is a drilling operation and Mechanical Specific Energy, MSE, is calculated according to the equation,
   MSE=( r )(Power)/( D   2 )(ROP)   
       in which:
 r is a constant for converting units of power to units of MSE; 
 Power is energy input to the machines used in the operation; 
 D is diameter of a bit used for the drilling; and 
 ROP is rate of penetration of the bit into a formation being drilled. 
 
     
     
         14 . The method of  claim 1  wherein said calculating is done in real time. 
     
     
         15 . The method of  claim 1  further comprising controlling the measuring and the calculating with a control system. 
     
     
         16 . The method of  claim 15  further comprising
 displaying calculated MSE in real time.   
     
     
         17 . A computer-readable media having computer executable instructions for a method as in  claim 1 , the method including measuring power input to machines used in drilling a wellbore and producing a value for input power, the computer-executable instructions performing the following step:
 calculating mechanical specific energy for the drilling based on a measured value for the input power.   
     
     
         18 . A computing unit configured to read and perform the computer-executable instructions on computer-readable media as recited in  claim 17 . 
     
     
         19 . The method of  claim 1  wherein the wellbore operation is a wellbore drilling operation and Mechanical Specific Energy, MSE, is calculated according to the equation,
   MSE=( r )(Power)/( D   2 )(ROP)   
       in which:
 r is a constant for converting units of power to units of MSE; 
 Power is energy input to machines used in the operation; 
 D is diameter of a bit used for the drilling; and 
 ROP is rate of penetration of the bit into a formation being drilled. 
 
     
     
         20 . The method of  claim 1  wherein said calculating is done in real time.