API Spec 12-1/2 Inch Tricone Drill Bits Of Roller Drilling Bit

API Spec 12-1/2 Inch Tricone Drill Bits Of Roller Drilling Bit

1 . Descriptions:

Steel Tooth (or Mill Tooth) bits come in many shapes and sizes with multiple features, and cutting structures to combat downhole diversities in the different formations you may encounter.

Mill teeth (Steel teeth) tricone are used in the soft rock formation . Wide gaps between the protruding teeth prevent them from becoming blocked with material as they cut through the top layer of material.

2. Specification:

3 . Bit profile 

4  . Bearing Types

There are primarily three types of bearing designs used in tricone drilling bits:

• STANDARD OPEN BEARING ROLLER BIT:

On these bits the cones will spin freely. This type of bit has a front row of ball bearings and a back row of roller bearings.

• SEALED BEARING ROLLERS BITS

These bits have an O-Ring seal with a grease reservoir for bearing cooling. The seals acts as a barrier against mud and cuttings to protect the bearings

• JOURNAL BEARING ROLLER BITS

These bits are strictly oil/grease cooled with nose bearings, O-Ring seal and a race for maximum performance.

5. Question :

What we should be pay attention on choosing the tricone drill bit ?

• IADC code passport
• TCI & Steel tooth options
• Additional tungsten carbide inserts on heel rows
• Tungsten carbide coating on cone bodies
• Diamond coated tungsten carbide inserts on the gauge of the cones
• Tungsten carbide inserts on the shirttail of the legs
• Additional central nozzle for cleaning cones

The tricone feature is that they come with their own passport as below :

• The specification of the cones
• The quality stamp signed by the person who made and checked the bit
• The recommended drilling parameters to get the best performance out of the bit:
• Bit weight
• Rotation speed
• Flushing volume

Which type of tricone you should choose ?

It depends on the geology you are drilling in and the diameters of the borehole you are drilling. The International Association of Drilling Contractors (IADC) have developed an easy use step system to choose the right tricone for your geology with additional features such as bit protection for longer production life.