Revolutionizing Drilling: Advanced Bit Solutions.
Composition and Product Series of API Standard TriCone Bits
1. Components of Tricone Rock Bits
Tricone Drill Bits are composed of five main parts: the drill bit body, leg, cones, bearing, and nozzle. For sealed jet bits, they also include a lubrication and compensation system.
2. Series of Tricone Drill Bits
① Diameter Series of Tricone Drill Bits
Domestic Drill Bits: The diameter series includes 15 sizes. Commonly used ones by Kingdream are 17 1/2", 12 1/4", 9 5/8", 8 1/2", and 3 7/8".
Imported Drill Bits: The diameter range is more complex. For example, drill bits from the U.S.-based Hughes Company cover 46 sizes ranging from 3 3/4" to 26".
② Coding of Kingdream Oil Tricone Bits
- The model code consists of four parts:
- Bit Diameter Code: Represented in inches, either whole or fractional.
- Series Code: Indicates the primary features of the bearing and sealing structure for the Three Cones Drill Bit, classified into nine categories.
- Classification Code: Three digits where:
- The first digit refers to the cutting structure and formation series.
- The second digit indicates the formation grade.
- The third digit denotes the structural features of the bit.
- Additional Structural Features: For special requirements, modifications are noted with one or more letters following the classification code.
Example:
- 8 1/2": Diameter of the bit.
- HJT: Sliding bearing with metal seal and special gauge protection.
- 537: Low compressive strength, soft to medium formations, TCI Tricone Bit.
- G: Strengthened leg.
3. Selection of Tricone Bits
The choice depends on data from similar formations in neighboring wells, formation conditions, and the specific well scenario. Consider:
- Formation hardness and abrasiveness.
- Depth of the drilled section.
- Inclined formations requiring anti-deviation drilling.
- Alternating hard and soft formations.
4. Judging Tricone Bit Conditions Downhole
①Normal Operation:
With consistent formation lithology, rotary table movement is uniform, drill speed remains stable, and indicators on pressure gauges are steady.
②Bearing Failure:
Periodic stick-slip movement of the rotary table, reduced drill speed, and fluctuating weight-on-bit readings.
③Cone Locking:
Increased rotary load, severe stick-slip, and difficulty in rotating the drill string.
④Dropped Cone:
Significant rotary load increase, abrupt stick-slip movement, and decreased penetration rate or no drilling progress.
⑤Worn Teeth:
Lighter rotary load, reduced penetration rate, and steady pressure gauge readings.
⑥ Bit Balling:
Increased rotary load, reduced penetration rate, and elevated pump pressure.
Diamond and PDC Drag Bits
1. Structure of Diamond Drill Bits
- Natural Diamond Drill Bits: Composed of a steel body, matrix, nozzle, and diamond particles.
- PDC Cutter Drill Bits: Include a steel body, matrix, nozzle, and polycrystalline diamond cutters.
①Profile Shapes
PDC drag bits feature three shapes:
- Parabolic:Suitable for soft formations, offering high drilling speed and stability.
- Circular:Ideal for hard interlayers due to concentrated hydraulics.
- Conical:Designed for strong penetration and stability in high-speed operations.
②Bit Selection
Consider factors such as drilling method, formation type, and drilling parameters when selecting a PDC Drag Bit.
③ Proper Usage Guidelines
- Maintain pump pressure above 13 MPa.
- Avoid collisions with hard objects and sudden impacts during drilling.
- Clean the well bottom thoroughly before starting operations.
- Use optimal drilling parameters: weight-on-bit (30–60 KN), rotary speed (117–217 RPM).
3. Coring Drill Bits
Coring drill bits are designed for annular crushing to extract rock cores. Common types include drag bits, tungsten carbide core bits, and diamond core bits. Features such as symmetry and wear resistance ensure high core recovery rates.