Abstract:

A lot research has been carried out in regard to the relationship between permeability and effective stress,but the final conclusions are different and enormous amount of controversy is caused.A new method is proposed in this paper.The permeability under original formation effective stress should be used as reference and the ratio of permeability under insitu stress to it should be used as evaluation criteria.The changes in permeability induced by the variation of formation pressure should include stress sensitivity and stress damage.According to the experimental data of core samples from DINA 2 gas reservoirs and the results of theory analysis，the stress sensitivity degree can be overestimated by using the permeability under conventional condition as reference than using the original insitu permeability.Both the stress ensitivity and stress damage of permeability can reflect the effect of elasticity and plasticity of core samples on permeability，the relationship between permeability and effective stress acquired by experiment under different stress path should be adopted in different developing stages.These conclusions can provide some useful help for evaluating the effect of changes in reservoir pressure on the gas well production correctly and designing the program of formation damage control.

Key words: permeability, effective stress, stressdamage, stresssensitivity, DINA 2 gas field, Tarim Basin