The terrestrial stress variation is a comprehensive triaxial change in nature.The traditional stress sensitivity experiment results do not match well with actual situation.In order to establish the relations between permeability and effective stress of carbonate gas reservoirs with ultra-high pressure

we designed two triaxial deformation experiments by using cores

one with and another without pore fluid pressure being con-sidered.Through experiments we established mathematical model for calculating permeability change based on experiment data and analyzed the relations between permeability and effective stress of carbonate gas reservoirs with ultra-high pressure in northeastern Sichuan Basin.The results show that the permeability declines more quickly in the experiment with pore fluid pressure being considered than that without pore fluid pressure being consi-dered under the same effective stress.The dimensionless permeability reduces by 57.48% for the No.3 core sample when the effective stress reaches 50MPa.For cores with well developed fractures

the experiment with pore fluid pressure being considered can better reveal the changing patterns of the permeability.In contrast

for those with poorly developed fractures

the experiment without pore fluid being considered works better for understanding the permeability variation of the matrix.Compared with other ultra-high pressure gas reservoirs both domestic and abroad

the reservoirs in the study area have higher stress-sensitivity.The experimental study provides a solid basis for highly efficient development of the gas reservoirs in the study area.