The supercritical CO

2

fracturing technology is yet to be improved

and the mechanisms of fracture generation and propagation are still not clear at present.In order to get an in-depth understanding of hydraulic fracture propagation behaviors and geometry under supercritical CO

2

fracturing

we introduced the Pen-Robinson equation to simulate the process of supercritical CO

2

fracturing

based on the displacement discontinuity boundary element method.Combined with lab physical simulation experiments

the differences of hydraulic fracture propagation behaviors and geometry between conventional fracturing with water-based fluid and fracturing with supercritical CO

2

in the shale reservoir were discussed.The results show that the pressurization in the pores of surrounding rocks will function to reduce the constraint of in-situ stress on fracture propagation

thanks to the diffusivity and good permeability of supercritical CO

2

and in turn the initiation pressure for fractures is lower than that of conventional fracturing.The incremental volumetric strain generated during and the failure of fractures after supercritical CO

2

fracturing are higher than those under conventional fracturing

thus the fracture geometry under supercritical CO

2

fracturing is more complex than that under fracturing with water-based fluid; meanwhile

the fracture plane under supercritical CO

2

fracturing is more complex and uneven

and has higher tortuosity than that under conventional fracturing with water-based fluid.