Objective The application prospects of supercritical CO₂ fracturing technology are broad, currently. It is necessary to ascertain crack initiation pressure and the law of fracture extension in supercrtical CO₂ fracturing in order to guide on-site application better.

Methods Based on this, considering the influence of temperature changes during the fracturing process on the physical properties of CO₂ and the thermal stress effect in rocks, a thermal fluid solid coupling supercritical CO₂ fracturing model is established. The effects of horizontal stress differences, natural crack approach angle and CO₂ injection temperature on fracture initiation are explored.

Results The on-site test was carried out in Well Y of Yangchungou. The results show that supercritical CO₂ fracturing can significantly reduce the fracture initiation pressure compared with hydraulic fracturing; Even under high levels of stress difference, complex crack morphology can still be obtained. The approach angle of natural fractures increases, the initiation pressure increases, and the complexity of fractures increases accordingly. The larger the difference between the CO₂ injection temperature and the formation temperature, the more obvious the thermal stress induction effect and the more complex the fracture morphology.

Conclusions On-site applications have shown that injecting pad injection supercritical CO₂ can effectively reduce the fracturing pressure, which is beneficial for improving the net pressure inside the fracture in subsequent hydraulic fracturing and improve the effect of reservoir transformation.