Supercritical carbon dioxide composite fracturing experimental device and experimental method

The invention provides a supercritical carbon dioxide composite fracturing experimental device and method.The experimental device comprises a core holder and a carbon dioxide supply device, the core holder comprises a clamping mechanism and a pressure applying mechanism, and the clamping mechanism comprises a left core chamber and a right core chamber; the pressure applying mechanism is used for applying pressure to the rock sample between the left core chamber and the right core chamber; a prepad fluid injection port is formed in the left end face of the right core chamber, and the carbon dioxide supply device is communicated with the prepad fluid injection port; the right end face of the left core chamber is provided with a prepad fluid discharge port, the left core chamber is further provided with a fracturing fluid injection port, the space between the left core chamber and the right core chamber is communicated with the fracturing fluid injection port, and the fracturing fluid injection port can inject f