How to Avoid Errors in Horizontal Directional Drilling Rig Guide Angle Adjustment

I. Core Preventive Measures

1. Adhere to the principle of fine-tuning: Control the change in inclination angle during a single correction to 2%~4%, avoiding "sudden and forceful adjustments" that could lead to reverse offset or S-shaped trajectory, ensuring a smooth borehole.

2. Strictly implement "measurement every 3 meters of drilling": Promptly detect lateral/longitudinal deviations (>0.3 meters) and initiate correction to prevent deviation accumulation.

3. Do not rotate during directional advance: During the direction adjustment phase, drill bit rotation must be stopped, and only axial thrust should be applied; otherwise, guidance will fail.

4. Retract to a stable section before correction: Before correction, retract 1~2 drill rods (3~6 meters) to ensure that the new trajectory starts from a reference point without offset.

II. Precise Control of Tool Face Angle
Use the directional control system to accurately adjust the guide plate to the target direction:

12 o'clock position → Upward correction;

6 o'clock position → Downward correction;

3 o'clock or 9 o'clock position → Right or left correction.

Immediately lock the drill rod after adjustment to prevent tool face deviation due to rotation.

III. Dynamic Adjustment Strategy Based on Formation

1. Soft Soil Layer: Prone to "drifting," shorten the measurement interval to 2 meters, use high-frequency fine-tuning, and reduce mud viscosity to minimize buoyancy effects.

2. Gravel Layer: Loose particles, it is recommended to use a bevel drill bit to enhance directional accuracy, combined with high-volume mud pumping to stabilize the borehole wall.

3. Rock Layer: Slow response, extend the directional advance time, strengthen mud cooling, and prevent equipment overheating leading to attitude control loss.

4. Alternating Soft and Hard Layers: Anticipate in advance, fine-tune the tool face angle to allow for compensation angles, and avoid "head-up/head-down" deviations.

IV. Technical and Management Support

1. Anti-interference Configuration: When constructing near high-voltage lines or metal structures, switch to wired sensors or activate a ground beacon system to avoid wireless signal distortion due to magnetic interference.

2. Real-time Data Comparison: Import the measured trajectory into the BIM 3D model and dynamically compare it with the design path to promptly identify trend deviations.

3. Standardized Recording and Verification: Complete the directional drilling construction record form, recording thrust, torque, pump pressure, and mud parameters for each drill pipe to facilitate problem tracing.

4. Enhanced Personnel Training: Operators must master the formation response patterns and correction logic, eliminating operations based on intuition.