Novel approach for assessing real-time bit working efficiency

A novel approach is studied for assessing real-time bit working efficiency and increasing controllability of drilling. Based on the previous mechanical specific energy theory, bit torque calculation is simplified and the confined compressive strength and related formula is proposed. In addition, the rate of penetration equation is deduced based on the correlation between parameters. The software of assessing real-time bit working efficiency is developed on the basis of the theoretical models above and is tested through field data. It can estimate bit performance by making use of log data, rock mechanical parameters, MSE, and mechanical efficiency. The results show that the predicted bit torque, CCS, EFF and bit performance are consistent with drilling field conditions and basically meet the requirement of drilling engineering. The method is instructive and meaningful to bit optimization, real-time drilling decision and analysis after drilling.