Underground supercharging and accelerating system

The invention relates to a matching device for petroleum and natural gas drilling operation, and particularly to an underground supercharging and accelerating system. The technical scheme is that the underground supercharging and accelerating system mainly includes a drill stem stress transmission assembly, a transmission torque pressure-bearing assembly, an elastic reset element assembly, a supercharging cylinder body, an ultrahigh pressure drilling fluid transmission assembly and a drilling bit, wherein the supercharging cylinder body is mounted inside the transmission torque pressure-bearing assembly, and the supercharging cylinder body and the transmission torque pressure-bearing assembly are relatively static; and torque is transmitted to the transmission torque pressure-bearing assembly through the matching of a spline on a spline mandrel of the drill stem stress transmission assembly and a spline outer cylinder in the transmission torque pressure-bearing assembly, so as to drive the drilling bit to break rock in a rotational manner. The underground supercharging and accelerating system has the benefits that as the spline is positioned at the top of the spline mandrel, the torque can be transmitted to the outer cylinder at the top of the system, so that load at the lower part of the spline mandrel is reduced, and the service life of the entire spline mandrel is prolonged; besides, the underground supercharging and accelerating system has simple structure and stable performance, and cannot bring danger of other aspects to the drilling operation during the use.