In order to study the physicochemical reaction law of carbonate rock reservoirs under the condition of CO

2

geological storage

lab experiments on the reaction of carbonate rocks and supercritical CO

2

under reservoir conditions were carried out with the carbonate reservoir of the Sinian Dengying Formation reservoirs in the Sichuan Basin as the research object. The response characteristics of carbonate porosity

permeability

and por

e structure to supercritical CO

2

environment were investigated by the pressure pulse attenuation method

scanning electron microscopy method

and nuclear magnetic resonance method. The test resulted in an increase both in the porosity and permeability of the carbonate rock. The maximum porosity change rate is 32.35 % and the permeability increases by eleven times. Additionally

micro-fractures appear after the test

and the proportion of the micro-fractures with the aperture of 20~50 μm increases. By using X-ray diffraction and contact angle techniques

the mineral makeup and wetability of carbonate rocks were examined. The average content of main minerals quartz increased by 12.6 %

the average content of calcite decreased by 22.3 %

and the hydrophilicity increased. Brazilian splitting technique was used to examine the mechanical characteristics of carbonate rocks both before and after supercritical CO

2

immersion. The tensile strength of carbonate rocks was discovered to have fallen by 18.28 %

causing damage to the rocks

and the compaction stage of the load-displacement curve was longer. This work examines the effects of supercritical CO

2

dissolution on the porosity

permeability

mineral composition

and rock mechanical characteristics of carbonate rocks

and provides theoretical evidence for the geological storage of CO

2

in carbonate reservoirs.