Under-balanced drilling rock-breaking simulation experimental device and method

The invention relates to an under-balanced drilling rock-breaking simulation experimental device and method. The under-balanced drilling rock-breaking simulation experimental device comprises a frame, a rotating system, a blowout prevention system, a high-pressure autoclave and a data collection and recording system; the top end of the high-pressure autoclave is provided with an active rotating assembly of the blowout prevention system; a sealing rubber core is arranged in the active rotating assembly; the top end of the high-pressure autoclave is closed to form a drilling fluid hydraulic chamber through the active rotating assembly which is provided with the sealing rubber core; a drill pipe penetrates the middle of the sealing rubber core to extend into the high-pressure autoclave; an annular horizontal load hydraulic chamber is formed in the high-pressure autoclave; the horizontal load hydraulic chamber surrounds outside a core gripper; a formation pressure hydraulic chamber is supported below the core gripper; the horizontal load hydraulic chamber and the formation pressure hydraulic chamber are located on a lifting supporting plate; the upper end of a plunger is connected with the lifting supporting plate; the lower end of the plunger is connected with a drilling simulation hydraulic chamber; the plunger is provided with a displacement sensor. According to the under-balanced drilling rock-breaking simulation experimental device and method, the movement condition that the rotating rock-breaking operation is performed through a drill bit under the underground conditions of under-balanced drilling is truly simulated and the indoor experiment support is provided for under-balanced drilling rock-breaking mechanism research.