The invention belongs to the technical field of
carbon dioxide sequestration and oil and gas reservoir yield increase transformation, and particularly relates to a
carbon dioxide acid fracturing method for ultra-deep well
carbonate reservoir transformation. The
carbon dioxide acid fracturing method for ultra-deep well
carbonate reservoir transformation is characterized in that the fluidity of a
system is controlled by adjusting the
viscosity of a CO2 composite acid liquor
system, acid liquor is composed of
hydrochloric acid with the concentration of 20%, a CO2 thickening drag
reducer and an atomization stabilizer, the acid liquor with different viscosities is obtained by adjusting the using amount of the CO2 thickening drag
reducer, and the CO2 composite acid liquor
system with the high
viscosity is suitable for making complex fractures at the ends of main fractures; the CO2 composite acid
liquid system with the
medium viscosity is suitable for making the complex fractures in the middle of the ends of the main fractures; the CO2 composite acid
liquid system with the low
viscosity is suitable for making the complex fractures around the main fractures of a near-well section. According to the carbon dioxide
acid fracturing method for ultra-deep well
carbonate reservoir transformation, the complexity of the reservoir fractures can be effectively improved, the volume of the fractures can be increased to meet the exploitation requirement, meanwhile, the
effective action range of the artificial fractures can be further increased, and the exploitation efficiency of carbonate reservoir oil and gas resources can be effectively improved.