Patent ID: 9598947
Date: 2017-03-21
CPC Classifications: E21B

Claim:
1. A method of drilling a wellbore, the method comprising: receiving surface measurement data regarding drilling parameters characterizing ongoing wellbore drilling operations, wherein at least one of the drilling parameters is controllable; determining rate of penetration (ROP) and mechanical specific energy (MSE) utilizing the received surface measurement data; utilizing a computer processor to calculate (i) a drilling performance measurement embodied in an objective function comprising a relationship between the determined ROP and the determined MSE, wherein the objective function comprises at least one of; wherein δ factor is added to the objective function to avoid a trivial denominator, SS is the stick slip severity, ROP 0 , MSE 0 and SS 0 are the nominal values for ROP, MSE and SS and are used in the objective function to provide dimensionless values, and ΔROP, ΔMSE and ΔSS are changes in ROP, MSE and SS between a current and a previous time step, or between a current and a previous depth location, and torsional SS can be either real time stick slip measurements transmitted from a downhole vibration measurement tool or a model prediction calculated from a surface torque and a drillstring geometry; and (ii) a mathematical correlation between the at least one controllable drilling parameters and the calculated drilling performance measurements of step (i); generating operational recommendations based upon the mathematical correlation for the at least one controllable drilling parameter; wherein the operational recommendations are selected to optimize the objective function of (i); determining operational updates to the at least one controllable drilling parameter based at least in part on the generated operational recommendations; and implementing at least one of the determined operational updates in the ongoing drilling operations.