Abstract:
China boasts abundant coal reserves, yet complex geological conditions and significant variations in coal seam occurrence pose challenges. As mining difficulty and safety risks increase, directional drilling technology has become increasingly critical in mine disaster prevention and hidden disaster factor detection. Precise control of drilling trajectories serves as a core technical component in ensuring safe and efficient coal extraction, optimizing operational efficiency, reducing costs, and enhancing safety. Since the 21st century, directional drilling technology has evolved through integration with the Internet of Things, big data, and artificial intelligence, progressing from experience-based manual operation to scientific precision, and further to automation and intelligence. The development status and limitations of key trajectory control technologies are elaborated, including single-bend positive displacement motor-based directional drilling, rotary steerable drilling, and measurement-while-drilling (MWD) technology. Single-bend positive displacement motor-based directional drilling is widely applied; However, during sliding steerable operations, the full potential of drilling rigs remains underutilized, while composite drilling processes lack trajectory adjustment capabilities. Rotary steerable technology, as a cutting-edge solution, enables real-time bit orientation adjustment via downhole intelligent systems, achieving “steerable-while-drilling” functionality. This significantly enhances drilling speed and control precision but exhibits insufficient build-up rates in coal seam applications. MWD technology provides robust support for trajectory monitoring and prediction, yet challenges such as signal attenuation, latency, and stratum interference persist. Through a comprehensive review of the latest domestic and international advancements in directional drilling technology and equipment development, future trends are explored. These include the integration of automation and intelligence in trajectory control, optimization and innovation of rotary steerable systems, multi-parameter MWD and transmission technology advancements, and collaborative innovation in equipment and processes. Such developments will guide the future evolution of drilling trajectory control technologies and continuously elevate the technical standards in this field.