Eggbeater PDC Drillbit Design Eliminates Balling in Water-Based Drilling Fluids

Abstract

This paper describes a novel polycrystalline-diamond-compact (PDC) -bit concept based on insights into PDC-bit cutting mechanism and rock behavior during drilling. The design comprises a hydraulic layout that optimizes bit cleaning and cuttings removal in soft and sticky formations. Significant improvements in performance have been achieved in Cretaceous and Triassic formations drilled with water-based muds.

Drilling Fluids

“…A polycrystalline-diamond-compact-bit has been developed [209]. This design comprises a hydraulic layout that optimizes bit cleaning and cuttings removal in soft and sticky formations.…”

Drilling More Stable Wells Faster and Cheaper with PDC Bits and Water Based Muds

“…The first and most common occurs when the chips do not separate from the individual PDC cutters and accumulate as a large mass of material (3,4,5) . The second, and only recently understood mode, is found when drilling with weighted WBM at high bottomhole pressures.…”

“…When shale material fails due to the cutting action, there is a sudden and large increase in formation porosity and a corresponding drop in pore pressure (3) . This phenomenon is known as rock dilation.…”

“…Depth of cut control through operating parameters and bit design features is another way to limit cuttings volume and size. More recent developments focus on chip management with sharp polished cutters (3) having aggressive rake angles and edge geometry.…”