We evaluate the feasibility of predicting seismic velocities based on drilling dynamics. In practice, drilling is often inefficient, resulting in the drilling dynamics losing correspondence with the mechanical energy required to penetrate a rock mass. Based on real data for a 1400 ft interval intersecting carbonate, clastic, and anhydrite formations, we show that downhole accelerometers provide sufficient information to distinguish the effects associated with the “drillstring noise” and rock properties. To this end, we modified the forward stagewise regression to provide a quantitative measure of the importance of various measurements while drilling. The three most critical features were found to be the intensity of axial vibrations (RMS of the accelerations in the 35-170 Hz range), mean specific mechanical energy (related to the drilling efficiency), and the rate of drill-bit penetration. The final regression equation provides much better goodness-of-fit for the challenging geological conditions compared to existing methods.
Presentation Date: Tuesday, October 13, 2020
Session Start Time: 1:50 PM
Presentation Time: 4:45 PM
Presentation Type: Oral