Flexible Tricone Rock Roller Bits 0.2-0.4 MPA High Strengths IADC Classified

IADC Classified Tricone Drill Bit For Wide Range Of Drilling Requirements

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What Is Tricone Drill Bit?

1. A roller cone or tricone rock bit consists of a bit body with three moveable conical rollers equipped with cemented carbide inserts.
2. The idea is the crush the rock by rolling the inserts against the rock with appropriate rotation speed and feed force.
3. Carbide inserts are distributed over the three rollers in such a manner that the entire bottom of the hole is worked on when the drill bit is rotated.
4. Roller bits for hard and abrasive rock generally have spherical cemented carbide inserts closely spaced.
5. Roller bits for softer rock may have the chisel and conical carbide teeth or quality milled steel teeth as the cutters.
6. Three types of cemented carbide inserts are used for roller type bits being Chisel, Conical, and Hemispherical.
7. A roller bit will utilize nozzles from which the compressed air escapes to lift the cuttings from the bottom of the hole.

We took the following factors into consideration when designing:

1. Journal Angle - Journal angle determines the overall aggressiveness of the bottom hole profile. Soft formation rock bits employ a 33 degree angle while hard formation rock bits employ a 36 degree angle.
2. Cone Offset - Increased rate of penetration (ROP) can be achieved by offsetting the ceter line of the cone away from the center of bit rotation. This produces more on-bottom action. The higher the offset the greater the scraping and gouging action on bottom.
3. Cone Angle –Oversize angle controls the diameter of the cone at gage.

Soft to medium formation tricones employ a more round cone profile and a larger cone angle. This creates a bottom hole action of gouging and scraping.

Hard formation bits employ a smaller cone angle and a flatter cone profile. This creates a bottom hole action of crushing.

1. Oversize Angle - Oversize angle controls the diameter of the cone at gage.

Soft formation tricones employ a higher oversize angle; thus, escalating gage action and cone diameter.

Hard formation bits have very little or no oversize angle. This reduces the action on gage and also reaming of gage inserts.

1. Intermesh - Intermesh is the distance the top of a tooth or button bit insert extends into the grooves of adjacent cones. This spacing allows for cleaning of formation and prevents packing.
2. Projection and Pitch - Projection is the height of the button or tooth. Pitch is the space between teeth or inserts.

Application:

Medium to Medium-Hard Formation

For use in moderately abrasive consolidated formations with compressive strength ranging between 140 – 485 Mpa such as hard limestone, quartzite, granodiorite, and medium grade metamorphic formations

Cutting structure: These bits are characterized by moderately spaced conical inserts with medium projection. This configuration promotes good penetration rates in medium hard and moderately abrasive formations. Smaller carbide inserts are provided on the gage and inner rows or hard metal is deposited in the nose area to contain shell erosion and improve performance.

• Weight on Bit (WOB): 2,500 – 7,000 lbs/in of bit diameter
• Compression Strength: 20,000 – 70,000 psi
• Drilling Speeds: 60 – 100 rpm
• Jet Circulation: All sizes

Common fault analysis of Tricone bits

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