How to determine whether the drilling speed of the Horizontal Directional Drilling Rig meets expectations?

1. Theoretical calculation and experience comparison
Theoretical calculation: According to the formation information provided by the geological survey report, combined with the performance parameters of the drilling rig, the type of drill bit and the selected drilling parameters, the expected drilling speed is estimated through the theoretical calculation formula. For example, for sandy formations, the relevant empirical formula can be referred to, and the approximate drilling speed range can be calculated based on the particle grading, density, drilling pressure, rotation speed and other parameters of the sand.
Experience comparison: Refer to the previous experience data of drilling speed under similar geological conditions and engineering scales. If there are successful cases in the same region or the same type of formation, their actual drilling speed can be used as an important reference. Compare the expected drilling speed of the current project with these empirical data. If the difference is not large, it is preliminarily judged that the drilling speed meets expectations.
2. Real-time monitoring and data analysis
Monitoring drilling parameters: During the drilling process, real-time monitoring of key drilling parameters such as drilling pressure, rotation speed, and feed speed. The stability of these parameters and the deviation from the expected set values ​​can reflect whether the drilling speed is normal. For example, if the drilling pressure and speed remain stable, but the drilling speed is significantly lower than expected, there may be problems such as drill bit wear and blockage in the hole.
Analyze the soil discharge: Observe the discharged soil, including the particle size, shape, water content and continuity of the soil discharge. Under normal circumstances, the soil discharged from different strata should have corresponding characteristics, such as fine and uniform soil particles discharged from sandy strata, and blocky soil discharged from clay strata. If the soil discharge is abnormal, such as the discharged soil contains a large number of unbroken large particles or the soil discharge is discontinuous, it may affect the drilling speed, resulting in the actual speed not meeting expectations.
Check the torque change: Torque is an important indicator of drilling resistance. By monitoring the change of torque, the working status of the drill bit and the change of the stratum can be judged. If the torque suddenly increases and continues to increase, it may be due to a hard stratum or a drill bit failure, which will cause the drilling speed to decrease; on the contrary, if the torque is stable and within the expected range, it means that the drilling process is relatively smooth and the drilling speed is likely to meet expectations.
3. Staged evaluation and comparison
Set staged goals: Divide the drilling process into several stages according to the total length and expected duration of the project, and set clear drilling length and time goals for each stage. At the end of each stage, compare the actual drilling length and time used with the set target value. If the actual drilling speed can reach or approach the staged goal, it means that the overall drilling speed is in line with expectations.
Compare drilling trajectories: Use the drilling trajectory data recorded by the guidance system to compare the deviation between the actual trajectory and the designed trajectory. If the drilling trajectory meets the design requirements and there is no frequent adjustment of the drilling direction due to deviation correction during normal drilling, it means that the drilling speed is within the controllable range and meets expectations. Otherwise, too many deviation correction operations will cause the drilling speed to decrease, which is not in line with expectations.
4. Consider the impact of external factors
Environmental factors: Consider the impact of the construction environment on the drilling speed, such as meteorological conditions such as temperature and humidity, and surrounding vibration interference. Under extreme temperature conditions, such as high temperature weather may affect the performance of the equipment and the work efficiency of the operator, and low temperature weather may cause changes in mud properties, etc., which in turn affect the drilling speed. When there are large construction equipment or traffic vibrations in the vicinity, it may also have a certain impact on the stability and drilling speed of the borehole.
Equipment maintenance and failure: The maintenance and failure of the equipment are also important factors affecting the drilling speed. Regularly maintain the drilling rig to ensure that all parts of the equipment are in good working condition and can perform normally. If an equipment failure occurs during the drilling process, even if the geological conditions and drilling parameters are normal, the drilling speed will decrease or even stagnate. Therefore, timely elimination of equipment failures and ensuring the normal operation of the equipment are the key to ensuring that the drilling speed meets expectations.