Abstract:
There are a series of problems in the drilling process of ultra-deep and ultra-long sections of 10 000-meter deep wells, such as severe vibration of the drilling string, slow speed of rock breaking, and short effective working life of the drill bit. Therefore, it is urgent to carry out research on vibration reduction of the drilling string and downhole energy enhancement technology of the 10 000-meter deep wells. According to the main characteristics of the ultra-deep drilling environment and recent research results on drilling string dynamics, a method was proposed to use drilling string vibration as an energy source during the drilling process to increase the jet pressure of downhole drilling fluid. While reducing drilling string vibration to protect the drill bit, the method increased the jet pressure of the drill bit to achieve downhole energy enhancement and rock breaking, solving the problems of high vibration intensity and insufficient hydraulic energy at the bottom of the wells. A vibration reduction and energy enhancement device for the downhole drilling string was developed, and on-site tests were conducted. The research results indicate that drilling string vibration contains enormous energy, which can be converted into energy for accelerating rock breaking. The designed vibration reduction and energy enhancement device for the downhole drilling string can increase the jet pressure of drilling fluid and reduce the safety risks caused by drilling string vibration, thereby significantly improving drilling speed. The research results have opened up new directions for the vibration reduction and acceleration technology of 10 000-meter deep wells and provided technical support for accelerating the exploration and development of deep oil and gas resources.