A High-Precision Temperature Compensation Method for Near-Bit WOB and Torque
Obtaining near-bit engineering parameters is of great significance for safe drilling.With the devel-opment of technology,the surface indirect measurement technology can no longer meet the actual drilling needs,and obtaining real-time parameters such as WOB and torque through downhole direct measurement are currently the main research direction.In the paper,based on the principle of strain measurement,a strain gauge sticking scheme and an electric bridge measurement scheme for measuring the downhole WOB and torque parameters were proposed.The experimental study shows that there is a nonlinear relation between the strain of mechanical structure itself and external load,and the nonlinear error is more prominent in hot environment.In order to improve the ac-curacy of measurement data,by means of simplifying the relationship between temperature,pressure and electric bridge output voltage,a mathematical model was built,and a coupling polynomial transformation matrix was used to conduct software compensation on the deformation error caused by the mechanical structure itself.The experi-mental results show that this method reduces the mean absolute error of directly calculating the force on strain gau-ges from 2.140 22 kPa to 0.277 39 kPa,a decrease of about 87%.This method effectively reduces the errors in measuring near-bit WOB and torque.
万方数据
维普
