What are the types of directional drilling in coal mines?
The underground directional drilling technology of coal mines provides effective technical means for underground coal mine gas drainage, water hazard prevention, and exploration of hidden disaster-causing geological factors. Real-time measurement and control of borehole trajectory is a key technology for directional drilling in coal mines. Measurement while drilling system and screw motor are the core equipment to realize real-time measurement and control of borehole trajectory. The measurement-while-drilling system is also known as the "eye" of directional drilling because it can realize real-time measurement and transmission of the drilling trajectory. According to the different data transmission methods, MWD systems are divided into two categories: cabled and cableless.
Wired measurement while drilling system
At present, the measurement-while-drilling directional drilling technology in the coal mine is mainly based on the wired measurement-while-drilling directional drilling. During the drilling process, the wired measurement-while-drilling system is used to monitor the borehole trajectory, and the measurement is transmitted through the wired channel formed by the central cable-type drill pipe. signal, the drill pipe performs directional drilling in a sliding manner.
Cableless measurement while drilling system
At present, the wireless measurement-while-drilling directional drilling technology in coal mines can be divided into mud pump pulse wireless measurement-while-drilling and low-frequency electromagnetic wave transmission wireless measurement-while-drilling.
YK Drilling Tools Industrial Brand Strength Factory
Next, we will focus on the cableless measurement while drilling system.
Mud Pump Pulse Wireless Measurement While Drilling
Mud pump pulse wireless MWD directional drilling technology is a new type of underground directional drilling technology developed based on mud pump pulse and composite directional drilling. It uses high-pressure flushing fluid as power and slag discharge medium to drive hydraulic screw The motor rotates and drills into broken rock, and carries the drilling slag produced during drilling; during the drilling process, the mud pulse wireless measurement while drilling device measures the drilling inclination angle, azimuth angle and hydraulic screw motor tool roll angle and other parameters, and takes the pressure pulse as the The signal carrier uses the flushing fluid in the drill pipe as the signal transmission channel, and transmits the measurement data in the hole to the orifice; the orifice adjusts the drilling trajectory according to the received measurement data; the drilling rig provides the drilling feed force, rotary force and fluid Moving screw motor tool roll angle adjustment power, etc.; pump truck provides high-pressure flushing fluid into the hole.
Low Frequency Electromagnetic Wave Wireless Measurement While Drilling
The measurement principle of the mining electromagnetic wave inclinometer is basically the same as that of other types of inclinometers currently on the market, but the transmission method of the measurement data is completely different. The mine electromagnetic wave inclinometer is based on wireless electromagnetic waves. A new measurement-while-drilling instrument for data transmission carriers. Drilling and construction personnel input measurement instructions through the real-time display and control software of the drilling trajectory on the orifice controller, and the main control circuit of the orifice controller encodes the instructions after receiving the instructions. And the electrode radiates the electromagnetic wave encoding signal carrying the measurement instruction information into the formation; the electromagnetic wave encoding signal carrying the measurement information propagates along the metal drill pipe and the formation to the direction of the bottom of the hole, and the electromagnetic wave encoding signal reaches the measurement position. Received by the transmitting/receiving antenna (insulation sub) connected to the measuring probe in the hole, the receiving unit of the measuring probe in the hole amplifies the received signal, demodulates the information to obtain the operation command, and starts the inclination measuring sub in time to complete the drilling at the current position. The attitude measurement of the tool; the measurement results carrying the measurement data information (inclination angle, azimuth angle, tool roll angle, real-time temperature) are modulated by the main control unit and the wireless electromagnetic wave transmission unit and radiated into the formation through the transmitting/receiving antenna; The rod and the stratum are transmitted to the outside of the hole. After the special transmitting/receiving antenna outside the hole receives the electromagnetic wave signal returned from the hole, the receiving conditioning circuit in the orifice controller amplifies, filters and demodulates the electromagnetic wave signal to obtain the current position. The original information of the drilling tool attitude is calculated and processed by the main control circuit and displayed in a graph by the real-time display and control software of the trajectory.
