What methods can be used to prevent deviations in horizontal directional drilling rigs?
May 13, 2026| I. Pre-construction preventative measures
1. Precise measurement and layout: Use a total station or GPS to verify the entry point, exit point, and rig positioning three times to ensure a straight line from the entry point to the exit point, with a deviation ≤0.1°.
2. Detailed geological survey: Understand the distribution of soft soil, sand, pebbles, and rock strata, as well as the location of underground obstacles, in advance to avoid the designed path crossing fault zones or areas with dense boulders.
3. Rational trajectory design: Scientifically set the entry angle (recommended 8°~15°), exit angle, and radius of curvature (≥1500D) to avoid excessively small curvature or frequent changes in direction.
II. Equipment and system support
1. Use a high-precision guidance system: Equip with a wireless guidance instrument, magnetic guidance, or gyro guidance system to monitor the drill bit position, depth, azimuth, and inclination in real time, achieving centimeter-level positioning.
2. Anti-interference configuration: When constructing near high-voltage lines or steel structures, use wired sensors or ground beacon systems to avoid data distortion caused by magnetic field interference.
3. Appropriate selection of drilling rigs and tools: Medium and large-sized drilling rigs are suitable for long-distance, large-diameter projects and have strong anti-deviation capabilities; for soft soil layers, use inclined drill bits to enhance guidance, and for rock layers, use roller cone or PDC drill bits to improve stability.
III. Construction process control
1. Frequent small-angle correction: Measure trajectory data every 3 meters of drilling. If a deviation > 0.3 meters is found, correct it immediately. The angle change for each correction should be controlled within 2%~4% to avoid sudden corrections that cause reverse deviation.
2. Dynamic adjustment of drilling parameters: Control the matching of advance speed and rotation speed, and dynamically adjust thrust and torque for different strata; avoid using the same parameters throughout to prevent "deviation" in alternating hard and soft strata.
3. Maintain stable mud performance: Prepare non-dispersible, low-solids mud with viscosity, specific gravity, and sand content meeting formation requirements (e.g., density of 1.03–1.20 g/cm³ for soft soil). Mud that is too thin is prone to "drifting," while mud that is too thick results in sluggish directional control response; a balance between wall protection and fluidity is necessary.
IV. Personnel and Management Support
1. Experienced operators are crucial: Experienced operators can accurately judge directional data, predict formation changes, and correct deviations promptly in the early stages.
2. Full-process recording and verification: Record drilling parameters for each drill pipe, and regularly compare measured data with design values. Data-driven management helps identify trend deviations.
3. Strengthen training and emergency plans: Complete technical and safety training before starting work, develop specific contingency plans for stuck drill pipe, broken drill pipe, and mud leakage, and equip the drill with salvage tools.
