Publications
Hard-rock field performance of drag bits and a downhole Diagnostics-While-Drilling (DWD) tool
A series of field tests sponsored by Sandia National Laboratories has simultaneously demonstrated the hard-rock drilling performance of different industry-supplied drag bits as well as Sandia's new Diagnostics-While-Drilling (DWD) system, which features a novel downhole tool that monitors dynamic conditions in close proximity to the bit. Drilling with both conventional and advanced ("best effort") drag bits was conducted at the GTI Catoosa Test Facility (near Tulsa, OK) in a well-characterized lithologic column that features an extended hard-rock interval of Mississippi limestone above a layer of highly abrasive Misener sandstone and an underlying section of hard Arbuckle dolomite. Output from the DWD system was closely observed during drilling and was used to make real-time decisions for adjusting the drilling parameters. This paper summarizes penetration rate and damage results for the various drag bits, shows representative DWD display data, and illustrates the application of these data for optimizing drilling performance and avoiding trouble.