Applications of Guide Plate Bits and Three Cone Bits

In horizontal directional drilling, there are many available types of bits for softer non-rock formations (soil or soil with sand layers), with the most commonly used in the industry being the guide plate bit and the three cone bit.

Comparison of Bit Advantages

Regarding adaptability to formations, the three cone bit is also suitable for soft formations such as soil layers, and the guiding accuracy can be ensured. If encountering formations with extremely weak bearing capacity, guiding plates can be added to the motor or joint by bending to achieve steering, offering great modification potential.

The effective drilling area of the guide plate bit is large, thus faster; however, the angle of the guide plate is large and fixed, showing different guiding accuracy in formations with varying hardness.

During construction investigations, the guiding accuracy of the guide plate bit is slightly inferior compared to the combination form of the three cone bit with a bending short connection.

Through comparison and analysis of the control group between guide plate bits and three cone bits, the following conclusions can be drawn:

• The guiding accuracy of the three cone bit is superior to that of the guide plate bit.

• In guided drilling, the various technical parameters of the three cone bit are easier to control compared to the guide plate bit.

• When drilling in compact sand layers, three cone bits should be given priority.

• When drilling in alternating soft and hard formations, three cone bits should be given priority.

• Tricone insert bits are also applicable for drilling in both soil and sand layer geology.

• In guided drilling, the guide plate bit saves more drilling time compared to the three cone bit.

• The guide plate bit creates larger hole diameters, which is more conducive to the return and recovery of the slurry.

Suggestions for Bit Selection in Construction

Through analyzing the working characteristics of guide plate bits and three cone bits in actual construction, the following suggestions are made:

• For large-diameter directional drilling crossings with strict guiding accuracy requirements, it is recommended to use three cone bits.

• For small-diameter directional drilling crossings with low guiding accuracy requirements or certain construction period requirements, it is recommended to use guide plate bits.

• For directional drilling of optical cable conduits specifically for hole formation, guide plate bits should be prioritized for guiding hole drilling.

• When crossing sand layers or areas with numerous sand layers, three cone bits should be prioritized; if the sand layer density is low, the steering capability can be adjusted by modifying the bending short connection with additional guiding plates.

• When using three cone bits to cross certain soft, weak bearing capacity soil layers, the steering capability needs to be adjusted by modifying the bending short connection with additional guiding plates.

• If a guide plate bit is required to cross some weathered soft rocks, using guiding plates with added alloy teeth and tapered designs can be considered.

• For guiding in particularly long, soft formation crossings, it is preferable to use guide plate bits.