Hard-Rock Drilling Performance of a Conventional PDC Drag Bit Operated With and Without Benefit of Real-Time Downhole Diagnostics

摘要

Sandia National Laboratories and Security DBS have collaboratively examined the hard-rock drilling performance of a conventional drag-bit design that was run in conjunction with field tests of Sandia's prototype Diagnostics-While-Drilling (DWD) system for acquiring real-time downhole and surface data. This effort constituted the first two phases of work under the terms of a multi-partner Cooperative Research and Development Agreement (CRADA) that has been established between Sandia and four bit manufacturers for the purpose of developing and demonstrating "best effort" drag bits that are capable of drilling difficult formations such as those commonly found at geothermal energy production sites. For both CRADA phases completed to date, the test bit (Security DBS, Model PD 5) drilled in the same well-characterized hard lithologic interval at the GTI Catoosa Test Facility near Tulsa, OK. In each case, extensive time-resolved downhole and surface data were acquired with the DWD system. During Phase 1, an experienced driller controlled the drilling parameters only on the basis of standard rig instrumentation readings. For Phase 2, one or more drilling engineers continuously observed the streaming DWD displays and actively guided the drilling process. Significantly different results were achieved in Phases 1 and 2 for penetration rate and bit life, which are reported along with bit damage assessments and representative data from the unique downhole measurement sub that monitored conditions at the bit. This information has supported the development of designs and DWD-based drilling strategies for the "best effort" bits being tested during CRADA Phase 3.