Advanced Cutting Structure Improves PDC Bit Performance in Hard Rock Drilling Environments

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractHard rock applications continue to pose serious challenges for PDC bits. Although improvements 1,2,3 have been achieved in these environments, PDC bit performance is highly inconsistent and leaves much to be desired.Operational costs in such environments, due to reduced footage and/or low penetration rates (ROP), are enormously high. This paper will evaluate the challenges of hard rock drilling. It will discuss the effects formation hardness has on drilling efficiency, and the energy level requirements associated with the different rock failure mechanisms.The definition and relationships between WOB requirements, drilling efficiency, ROP, wear flat generation and on-bottom drilling time will also be discussed.An advanced cutting structure (ACS), which improves PDC bit effectiveness and consistency in hard rock drilling environments, will be presented. ACS improves drilling performance by redefining and optimizing the relationships between ROP, durability and stabilization. It maximizes bit life, by slowing the PDC cutter deterioration process, without compromising ROP. This paper will describe ACS's functionality, and show the positive effects it is having on operational costs. Laboratory and field data, supporting ACS's effectiveness will also be presented. Minimizing PDC Cutter DeteriorationAccelerated PDC cutter deterioration, either through wear or impact damage, reduces durability and drilling efficiency. To improve PDC bit performance, especially in hard rock drilling environments, cutter deterioration must be drastically delayed.

Mathematical modelling of performance and wear prediction of PDC drill bits: Impact of bit profile, bit hydraulic, and rock strength

“…It has been reported that the abrasive wear occurred caused by low DOC, while high DOC caused an impact wear (Van Quickelberghe et al, 2006). The wear occurs while the bit is rotating but not cutting (Mensa-Wilmot et al, 2003). This was confirmed by Gouda et al (2011) who stated that no torque leads to wear.…”