Hallibuton bit Course

Roller Cone Bits

– Milled Tooth Bits

Roller Cone Bit Components Arm Pin Reservoir System Cone Shirttail Jet Nozzle/Bore Jet Nozzle Nail Lock Gage Seam Weld

RC Drill Bits

 Cutting Structure (MT or TCI)

 Teeth shape and projection

 Bearing type (sealed or open)

 Bearing type (friction or roller)

 Compensation system

RC Bit Geometry – Journal (or Pin) Angle

 Basic element in the design of cone

 Angles

– Soft formations - 33° – Hard formations - 36°

 Influences the cone contour (profile) and aggressiveness

Centerline of Bit

Journal Angle

Journal (Pin) Angle

Soft Formation Hard Formation

Journal Angle OversizeAngle Of Cone &Journal Of Bit Journal Angle Cone Angle Of Cone & Journal Cone Angle Oversize Angle

Cone Angle

 Large Cone Angle

– Soft to Medium Formation – Rounder cone profile

– Gouging & Scrapping

 Small Cone Angle – Hard Formation – Flatter cone profile – Crushing

Direction of Rotation - Bit

Offset

Direction of Rotation - Cone

Offset

 Increased ROP in soft formation

 More offset increases gouging and

scraping (action on bottom)

 Less offset for medium

formations

 Little or no cone offset for hard formation

 Weight applied to crushing

rock

Offset Offset

Soft Hard Journal Angle OversizeAngle Of Cone &Journal Of Bit Journal Angle Cone Angle Of Cone & Journal Cone Angle Oversize Angle

 Soft formation bits

– higher oversize angle

– Increases action on gage, cone diameter, reaming

 Hard formation bits

– little to no oversize angle

– Reduces action on gage, cone diameter, reaming

Intermesh

 Prevents packing of formation

 Better use of space for the cutting structure

 Greater cone shell thickness

 Extended tooth/insert length

 Larger bearing size

Projection and Pitch

 Projection is the height of the tooth (Aggressiveness)

 Pitch is the spacing between the teeth

(Agressiveness and Anti-tracking feature)

Projection

Insert Bit Cutting Structure

20 Ovoid

28 Diamond Enhanced Ovoid

24 Hemispherical 30 Conical

38 Diamond Enhanced Conical

40 Double Conical _{58 Diamond Enhanced Tooth}50 Tooth 55 Spear Shaped Tooth

60 Shaped Gauge

68 Diamond Enhanced Shaped Gage

65 Angled Shape Gauge

66 Diamond Enhanced Angled Shaped Gage 10 Surf

Insert Bit Cutting Structure

Diamond Enhanced Inserts  Maintain Bit Gage

 Diamond surf protection used

in 33% (D), 50% (D2) and 100% (D3) increments

 Reduce shirttail wear in directional and horizontal applications 33% Increment 50% Increment 100% Increment Diamond

Roller Cone Technology

Cutting

Efficiency

Optimization

Roller Bearings

Large Diameter Bits

 Larger than 13 ½”

 Low friction

 Reduces heat

Non-Sealed Roller Bearing

 Tooth cutting structures

 Generally for top hole and cement drilling applications

Double Sealed Roller Bearing

 Rollers captured in arm

 Single compensation system

 Insert and Tooth

 Generally for rotary and motor applications

Spring-loaded face seal

• Radial seal

Premium Double Sealed Roller Bearing

 Larger than 15”

 Rollers captured in cone

 Dual compensation system

 Insert and Tooth

 Generally for motor or high energy applications

• Tandem radial seals

Sealed Journal Bearings

Smaller Diameter Bits

 13 1/2” and smaller

 Insert and tooth

 O-ring Seal

 Friction bearing

 High load capacity

 Silver plated to reduce friction

Thrust Bearing Improvements

 Increased load bearing surface area 11% (green)

 Reduced pilot pin diameter

 Virtually eliminate thrust bearing slot

Improve Bearing lubrication through enhanced grease

communication (Heat cooling and pressure compensation)

High Energy Standard

Advanced Diamond Hardfacing

 Ample hardfacing is

applied to flanks, crests and gage surfaces for maximum wear

resistance

 Steel teeth are

sculptured in high wear areas for added

hardfacing material

Fluid Circulation

 Purpose

– Remove cuttings

– Keep the cutting structure clean – Cool the bit

– Stabilize the borehole wall – Shales inhibition

– …etc

 Drilling fluid

– Liquid (water or oil-based) – Air, Aerated Mud

Bit Hydraulics

• With high pressure drop across the nozzles, high velocity fluid flows past the cones and impacts against the formation, flushing out cuttings in the hole

Arm

Drilling Fluid

Nozzle

Center Jet (if equipped)

Roller Cone bit Selection vs Formation Hardness

R o c k c o m p re s s iv e R O P H a rd n e s s s tre n g th (p s i) ft/h r V e r y s o f t < 4 , 0 0 0 > 7 0 S o f t 4 , 0 0 0 - 8 , 0 0 0 3 5 - 7 0 m e d iu m 8 , 0 0 0 - 1 6 , 0 0 0 1 5 - 3 5 H a r d 1 6 , 0 0 0 - 3 2 , 0 0 0 1 5 - 5 V e r y h a r d > 3 2 , 0 0 0 < 5 R o c k c o m p re s s iv e R O P H a rd n e s s s tre n g th (p s i) ft/h r V e r y s o f t < 4 , 0 0 0 > 7 0 S o f t 4 , 0 0 0 - 8 , 0 0 0 3 5 - 7 0 m e d iu m 8 , 0 0 0 - 1 6 , 0 0 0 1 5 - 3 5 H a r d 1 6 , 0 0 0 - 3 2 , 0 0 0 1 5 - 5 V e r y h a r d > 3 2 , 0 0 0 < 5

HDBS Roller Cone Technology – Cutting Efficiency Optimization

Force & Energy Balancing

Force Balancing

• Force Balancing  Reduced vibration

 Lower impact damage to CS  Extended Bearing / Seal life by

reducing wobble motion of cones

 Improved Directional  Responsiveness  Increased ROP

Cutting Efficiency Optimization

• HDBS Unique Anti-tracking Feature (Insert Orientation)

Double Positive Seals

• Dual compensation system permits use of two positive seals to extend bearing life

• The high aspect ratio seals provide additional squeeze with low stress levels resulting in lower operating temperatures

Seal Design Improvements

487 Double Seal C29 Double Seal C49 Double Seal

• Grease hand-packed in cavity between seals • No means to equalize pressure between seals

• Grease hand-packed in cavity between seals • Series of small filtering holes in outer seal to equalize between seals pressure

• Cavity between seals vacuum filled with lubricant • Dedicated reservoir to equalize pressure between seals

• Radial seal and spring-loaded face seal

• Radial seal and modified face seal

Improved Bearing Design

Capacity Increase vs. Previous Designs

487 C29 C49 57% B B A A A B 76% 24% 12% Bearing A Bearing B

Roller Bearing Radial Load distribution

• Greater distance between roller bearing centers improves load distribution

A

B

Typical loading diagram

Bearing loads calculated as resultants of moments generated from weight on bit

M

• Longer roller bearing elements increase bearing capacity

• Combined improvements extend expected bearing life

487 C29 C49 A B A B A B Relative life expectancy 1.0 2.9 5.4 8.8 7.1 9.4 Bearing code

Optimizing Technology

 Bearings system optimized using Bearing Simulation Software, FEA and custom laboratory testers for

Optimized Contact Pressure Profile Seal

• Highest contact

pressures at the edge of sealing interface where it is needed.

• Lower contact pressures reduce heat and torque at center of sealing face. • In controlled laboratory

testing:

• 53% increase in seal life

• 24% reduction in torque

Optimized Contact Pressure Profile

0 50 100 150 200 250 300 350 400 0 0.05 0.1 0.15 0.2 0.25

Contact Pressure (psi)

Contact Length (in.)

Standard O Ring

New Seal

 Sealing mechanics. High Aspect Ratio Seals

 Developing improved thermally stable and wear resistant elastomers

 Dome compensation and mechanical pressure relief

 Increased reliability & repeatability

 Reduced hysteresis

 Improved seal condition due to consistent pressure

 Flexibility with mechanical spring to adjust relief pressure

Mechanical Pressure Compensator (MPC)

Optimizing Technology

 Enhanced and Directed Hydraulics

– Remove cutting from crucial areas (sealing area & CS) – Improved arm geometry

– Directed flow channels

Optimizing Technology

 Bit Cleaning

Bit Cleaning – Low Flow Under Cutting Structures

BEFORE

Bit Cleaning – Higher Flow; Higher ROP

Optimizing Technology

 Controlled Upward Flow

Controlled Upward Flow – Effective Cuttings Removal

Optimizing Technology

 Forging Design

Old Forging Design New Forging Design –