Patent ID: 9217328
Filing Date: 2015-12-22
Classification: E21B

Abstract:
1. A method, comprising: positioning a downhole tool in a wellbore extending into a subterranean formation; commencing coring operations by rotating a coring bit of the downhole tool and extending the rotating coring bit into a sidewall of the wellbore; measuring a rotating speed of the coring bit using a bit rotating speed sensor; measuring a rotating speed of a bit rotation motor using a bit rotation motor speed sensor; computing via a controller a ratio of the measured rotating speed of the coring to the measured rotating speed of the bit rotation motor; comparing via the controller the computed ratio to a target ratio of the measured rotating speed of the coring to the measured rotating speed of the bit rotation motor; and automatically adjusting via the controller a rotating speed of a weight on bit (WOB) motor based on the comparison of the computed ratio to the target ratio.