Drone-based method of subterranean directional drilling control

A method of controlling the position of a subterranean directional drilling tool in relation to a de sired subterranean drill bore path using a system comprising:

• a. a directional drilling tool capable of drilling within an as sociated subterranean drill bore, said drilling tool having a control bus capable of receiving control inputs to control the operational drilling direction of the tool;
• b. a magnetic tool target attached to the drilling tool for emission of a detectible magnetic field;
• c. at least one UAV capable of controllably hovering or landing at a above-ground sensing location and comprising:
• i. a tri-axial magnetometer capable of detecting the magnetic field emitted by the magnetic tool target and yielding detected magnetic field data from which the di stance and position of the drilling tool in relation to the UAV can be determined;
• ii. a GPS receiver capable of receiving GPS signals identifying the terrestrial location of the UAV, being UAV position data;
• and
• iii. a network interface whereby detected magnetic field data and UAV position data can be transmitted to a computer in operative communication with the control bus of the tool;
• and
• d. a computer comprising:
• i. a processor;
• ii. a memory storing the terrestrial drilling coordinates of the desired subterranean drill bore path;
• iii. a network interface capable of communication with the at least one UAV and receiving data transmitted therefrom;
• iv. a control bus connection to the control bus of the drilling tool;
• and
• v. a positioning software component comprising processor instructions by which the computer can facilitate the necessary steps of the method;
• said method comprising, by operating the system:
• a) actuating the drilling tool to drill in estimated accordance with the stored terrestrial drilling coordinates;
• b) positioning each UAV at a selected sensing location in proximity to the intended alignment of the desired subterranean drill bore path, within detection range of the magnetic tool target by the magnetometer;
• c) periodically, in respect of each UAV, capturing detected magnetic field data in relation to the magnetic tool target using the magnetometer and the terrestrial location of the UAV using the UAV-based GPS receiver, and transmitting the detected magnetic field data and UAV position data to the computer;
• d) in a location resolving step, on receipt of detected magnetic field data by the computer from any of the UAVs:
• a. calculating the relative target location of the magnetic tool target in relation to the corresponding magnetometer using the received detected magnetic field data;
• b. mathematically combining the UAV position data with the relative target location to yield a terrestrially referenced location of the drilling tool;
• c. comparing the terrestrially referenced location of the drilling tool to the stored terrestrial drilling coordinates of the desired subterranean drill bore path and determining any necessary change in operating drilling direction of the drilling tool to maintain the terrestrial drilling position of the tool as closed to the desired drill bore path as possible;
• e) if any change in drilling direction is required, providing an as sociated control input to the drilling tool via the control bus;
• and
• f) periodically actuating movement of each UAV to a desireable sensing position along the drill bore path a s the drilling tool advances;
• wherein during operation of the system the periodic detection of the drilling tool position and adjustment of the operating drilling direction will result in an optimized adherence of the drilling tool to the desired subterranean drill bore path.