Technology Update: Directional Hybrid Drill Bit Pushes Performance Standards

Abstract

Technology Update It is inspiring to look back to 1909 when Howard Hughes Sr. and Walter Sharp introduced the roller-cone bit. The invention was the foundation for the discovery of vast amounts of oil in medium-and hard-rock formations, oil that many drillers suspected was there but was nearly impossible to reach with the bits of that day. The roller-cone bit changed the industry, but we may forget why its immediate predecessor, the fish-tail bit, was such a burden on drillers as they strived to probe deeper targets. Often 24 hours would not go by without a twist-off occurring, and rig hands were constantly changing bits and “fishing” parts out of the hole. For drilling anything other than loose formations near the surface, it had proved impractical. In a century’s time, the industry has made tremendous progress. But the limitations of physics continue to challenge the dynamic performance of the bit and bottomhole assembly (BHA) in the demanding downhole environments of today’s wells. Tools come equipped with features such as torque reducers, depth-of-cut controls, and more flexible assemblies, to mention a few. The inherent problem of controlling the reactive torque between the bit and formation, while achieving optimal performance to reduce the number of drilling days, has remained a challenge. The introduction of the hybrid drill bit in 2011, which combined roller cones and fixed cutters, was a catalyst to revisit these basic principles and better understand the benefits and efficacy of smooth drilling. The bit excelled in controlling torque fluctuations and exceeded the durability of fixed-cutter bits and the penetration rates of roller-cone bits. The hybrid bit soon became the standard bit for drilling in hard and interbedded formations, such as those in certain Oklahoma and Canadian plays, because it enabled drillers to reduce the number of curve runs needed. The use of the bit expanded globally, helping to improve drilling results in interbedded applications that historically have met with mixed success when medium-set roller cone or fixed-cutter bits have been used. As results continued to improve, interest in stretching the capability of the technology increased.