An Improved Lateral Vibration Displacement Estimation of Drilling Strings Based on Double Accelerometers Installed Symmetrically

Drill string dynamics could be analyzed by the displacement cloud map of lateral vibration. The displacement can be obtained from acceleration signals and a double integration process. However, existing real-time methods ignored the effect of sensor installation position and thermal noise, both factors severely degrade the accuracy. Based on the Kalman filter, a procedure was developed to estimate the lateral vibration displacement near the bit in real time. Two symmetrically mounted biaxial acceleration sensors are used, and the data acquisition and processing circuit is a DSP+FPGA structure. Experiments in the laboratory prove that the method has high accuracy which is a practical reference.