Experimental studies on the short term effect of CO2 on the tensile failure of sandstone

摘要

The injection of CO2 to the formation may cause the tensile failure of the formation rock. The short term effect of CO2 on the tensile failure behavior of sandstone with or without the combined effect of water was investigated in this paper. Hollow cylinder method was adopted to fracture the sandstone samples under four types of pore fluid condition: dry, dry with CO2, water wet and wet with CO2. The experimental results indicated that the effective fracturing pressure of the samples under the same pore fluid condition varied linearly with the effective confining pressure in the range of 1.0-6.0MPa. Existence of water resulted in a slight weakening of 5.638% on the tensile strength. But the tensile fracturing behavior of the sandstone was not obviously affected by gaseous CO2 with or without the combined effect of water. The findings can be a reference for the mechanical stability evaluation of the formation in CO2 storage.