The basic function of HDD drilling rig is to realize guided feeding, rotation and reaming pullback, rotation and long-distance pullback of the lifeline to be laid, and at the same time provide a carrier for the angle adjustment of the trajectory. Drilling tools mainly include drill rods, screw drilling tools, transfer cases, etc., to achieve effective transmission of force and torque. Drill bits include pilot bits and reaming bits, which are generally in the form of cemented carbide, PDC, etc. according to the characteristics of the formation. The mud circulation equipment includes mud pumps, solid control equipment, pipelines, mud tanks, etc. Lubrication, wall protection and other functions.
The independent research and development of HDD in China started relatively late. In the mid-1990s, a series of drilling rigs with a drag force of less than 50t were successively developed. These types of drilling rigs have poor performance, small adaptability, and low degree of automation of the drilling rigs, although hydraulic control is used. technology, but mainly uses the motor as the power source, which cannot meet the needs of field operations and has fewer functions. After 2000, large-tonnage drilling rigs have been developed in China, and they have adopted full load-sensitive control technology, rubber crawler walking chassis, and diesel engine as the power source. According to actual engineering needs, they can be assembled in two ways: integration and separation. The automation of drilling rigs The degree of improvement has also changed the situation that drilling rigs above 200t are dependent on imports. At present, the world’s largest pulling force is the 2000t split electric drive HDD drilling rig designed and manufactured in China. The drilling rig consists of a power station, a power head, a feeding mechanism, a gripper, a drilling frame, an ground anchor, a control table, a manipulator and a mud pump, etc. part composition.
The world’s largest pulling force (20,000 kN) HDD drilling rig
Using the power system connected to the grid to replace the diesel engine as the power source to drive the drilling rig can effectively reduce noise and pollution, as well as reduce the consumption of fossil energy, simplify the mechanical transmission structure, improve the transmission efficiency, and easy to achieve automatic control.
While HDD drilling rigs are developing to large-scale, automation, intelligence and informatization have also become the focus of research and application. The working condition parameter detection platform relies on the LabVIEW virtual instrument program, through the USB data acquisition card, serial port and 6 sensors, to dynamically measure the rotary pressure, feed force, mud pressure, rotational speed, ROP and mud flow rate to achieve real-time detection, real-time Display, overrun alarm and data saving and playback functions.
On this basis, the programmable logic controller (PLC) intelligent control technology can realize intelligent judgments such as operator presence protection, interlocking functions of getting on and off, logic function interlocking, and anti-misoperation protection. The result ensures that the HDD rig can automatically stop and alarm under extreme conditions. The remote control of HDD rig can be realized by installing wireless receiver controller circuit on the rig and applying IoT technology. The wireless controller inputs the switch quantity control signal through the button switch, the analog input control signal through the spherical knob, and the wireless module converts the analog signal into the corresponding digital quantity signal. After receiving the digital signal and the digital signal, the wireless receiving controller restores the digital signal to an analog signal, and uses the digital signal and the analog signal to control the on-board equipment to realize the automatic control function.
The Web-based remote monitoring system can also realize remote control. The system consists of an information acquisition terminal and server-side software. The information acquisition terminal with an 8-bit single-chip microcomputer as the main control chip collects the operating parameters of the drilling rig, and sends and controls the drilling rig in real time. The server side processes the received drilling rig data through Java serial communication technology and stores it in the MySQL database, and dynamically publishes drilling rig parameters to achieve effective monitoring and systematic management of HDD drilling rigs.
Aiming at the problem of insufficient torque of screw drilling tools in long-distance HDD, a high-torque combined screw drilling tool is designed and developed. The drilling tool consists of a common shunt joint, an independent screw drilling tool, a lubrication system, a bundled centralizer, a combined transmission system and an oil-sealed transmission shaft system. Each screw drilling tool is arranged in parallel, and torque synthesis and motion transmission are realized through a quadrilateral mechanism.
1—Common shunt joint; 2—Independent screw drilling tool; 3—Lubrication system; 4—Binding centralizer; 5—Combined transmission system; 6—Oil-sealed transmission shaft system
The position information of drilling tools in underground space is usually obtained by using a fluxgate magnetometer based on the direction of the earth’s magnetic field and a pendulum inclination sensor based on the direction of the earth’s gravity. Under the influence of external electromagnetics, this method is not accurate. . Using 3-axis micro-accelerometer and 3-axis magnetoresistive sensor as attitude sensitive devices, real-time acquisition of azimuth, inclination and roll information of drilling tools in directional drilling can effectively overcome the shortcomings of traditional drilling tools. The system has a series of advantages such as small size, low cost and high reliability, and is very suitable for shallow underground directional drilling measurement.
The pipe pusher is mainly used in long-distance HDD projects, and it is a lifeline assisting equipment. In engineering, a clamping device is generally used to fix the pipeline, and the fixed pipeline is moved along the axis of the pulling direction by means of a propelling cylinder or mechanical force. The pipe pusher is generally installed at the entry point, and has the advantages of stable assist, controllable speed, and large thrust, so as to ensure the smooth completion of the lifeline pullback.
The thrust of the pipe pusher is generally provided by the push-pull cylinder, and the force is transmitted through the 4 clips that hold the pipeline tightly. The clamping and release of the clips are realized by the clamping cylinder at the bottom of the clip. In order to prevent the contact surface between the clip and the steel pipe coating from being clamped and damaged, a 10-12 mm rubber coating is vulcanized on the contact surface between the clip and the pipe. balanced. At the same time, the rubber coating is grooved for drainage and slag discharge to ensure sufficient friction. When the cylinder is under the load of shrinking the cylinder, the pusher is in the push mode; when the cylinder is under the load of the extension cylinder, the pusher is in the working state of the pull mode.