Fluid-dynamic aspects of the performance of diamond drill bits used in rotary rock drilling

Technical Report · Wed Sep 01 04:00:00 EDT 1982

OSTI ID:6222723

Sundaram, T R

As in deep-hole drilling with any other type of rock bit, drilling with diamond bits can be envisioned to consist of two more or less separate parts. The first is the breaking of the rock by the diamond cutters and the formation of rock chips, while the second is the removal of these chips away from the cutting zone by a circulating mud slurry which flushes the drill-bit face. The second part, or hydraulics, is quite important in determining the overall drilling performance. The present study is a theoretical investigation, based on phenomenological grounds, of the factors influencing hydraulics. Hydraulics is viewed as consisting of two separate steps, that of the establishment of a mud velocity distribution on the bit face and that of the acceleration of the rock chips, away from their sites of formation, by the mud flow. The analyses are utilized to relate hydraulic performance to operational parameters (bit weight, speed or rotation and mud circulation velocity), to drill-bit characteristics (number and sizes of diamonds, number and sizes of watercourses, etc.), to mud characteristics (density and viscosity), and to formation characteristics (strength, pore pressure, etc.). Some numerical examples are also presented, and are compared with available experimental and theoretical data.

• Research Organization: T.S. Associates, Inc., Columbia, MD (USA)
• DOE Contract Number: FG01-81ER10995
• OSTI ID: 6222723
• Report Number(s): DOE/ER/10995-T1; ON: DE83004212
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
422000* -- Engineering-- Mining & Underground Engineering-- (1980-)
DRILL BITS
DRILLING EQUIPMENT
DRILLING FLUIDS
EQUIPMENT
FLUID MECHANICS
FLUIDS
HYDRODYNAMICS
MATHEMATICAL MODELS
MECHANICS
PERFORMANCE
ROCKS
VELOCITY