IADC Code Upgrade: PDC Bit and BHA Forensics Using Rig-Based Photographic Documentation Practices

Abstract

Summary This paper establishes uniform recommended industry practices for photo documentation of polycrystalline diamond compact (PDC) bits and bottomhole assemblies (BHAs). These recommended practices were developed by a subcommittee of the joint International Association of Drilling Contactors (IADC)/Society of Petroleum Engineers (SPE) industry in an effort to upgrade the IADC dull grading practices. Effective field photographic documentation and training to identify the causes of damage enables the team to modify parameters used and make other immediate changes in the BHA/drilling system with a higher degree of confidence that they will increase drill rate or extend bit life. The field documentation also provides the basis for more detailed post-drill shop grading and extensive redesign, if needed. The recommended photographic documentation consists of a specific set of photos of each blade, a top view, a side view, and views of each contact point in the BHA (i.e., kick pads, stabilizer blades, and reamers). It is common for rigsite teams to take photos of bits pulled, but these have not historically provided the detail required to distinguish one potential cause from another. There are proven changes in practices or BHA configuration that can be made to mitigate each type of dysfunction, but this cannot occur unless the cause is identified correctly. Appropriate photographic documentation, when coupled along with an understanding of the different PDC cutter and bit damage mechanisms which may occur, enables the rigsite team to identify the dysfunction and implement the changes needed. While other data sources, such as digital drilling data, should be analyzed to estimate the event timing and confirm the cause, the damage that is observed in the photographic documentation plays a critical role in directing the actual redesign effort. For example, downhole accelerometer data may indicate the presence of BHA whirl, but whether this damages the bit in a given situation is dependent on formation hardness and other factors. Whirl may not be the priority of redesign unless the photographic documentation shows a pattern of damage that is known to be specifically due to BHA whirl. These photographic documentation practices were developed specifically to support drilling forensics. The guidelines were compiled from the practices of multiple operators, bit manufacturers, and service companies with significant experience in utilizing similar photographic documentation to support timely rigsite decisions. The photographic documentation is not complex and experience has shown that within a short period of training and daily discussions, the collection of high-quality photos becomes a routine, sustainable practice. To obtain the greatest value from photographic documentation, operators must also develop training for field personnel in how to recognize the dysfunction that caused the damage. This document is intended to both standardize field photographic documentation practices and provide training material appropriate for field personnel on how to suitably document bit and BHA components using photos.