A comparative study of fracture surface roughness and flow characteristics between CO2 and water fracturing

Fracture surfaces were measured using a 3-D optical topography scanner, and the fracture surfaces caused by CO2 fracturing are much rougher than those caused by water fracturing due to the stronger penetrability of CO2 through tiny pores and channels. The fracture roughness of siltstone with intensive macro-pores is greater than that of shale, because fractures preferably propagate along the orientation of macro-pores. Fracture flow conductivity...