The Status of Current Research on Downhole Robots and their Multiple Applications

The research and application of downhole robots has been carried out at home and abroad for addressing the difficult RIH of logging and fracturing pipe strings in horizontal wells. Two categories of downhole traction robots and drilling robots have been determined based on the structural characteristics and functions of downhole robots. The functions, design schemes and performance parameters of four key technologies, including support structure, drive system, control system and energy supply system were introduced in detail and the latest research progress of downhole robots at home and abroad were summarized. Studies indicated that the researches of downhole robots could be focused on the miniaturization and safety, and the telescopic intelligent control drilling robots should be developed preferentially. Based on the development of downhole robots, forward-looking technologies such as multi-lateral micro-hole horizontal well completion, coiled tubing intelligent closed-loop drilling, wireless single bridge plug staged fracturing in horizontal wells, etc., have been advanced. This paper provides a guide for the research, design and application of downhole robots in China.