The invention discloses a
shale gas reservoir gas
diffusion coefficient experiment test method. According to a method, a one-dimensional
diffusion mathematic model is built by
monitoring pressure attenuation data in a shale
plunger rock sample under
effective stress conditions of
methane gas with a certain initial pressure in a constant-temperature
closed system with the micro-pore structure and the gas existence state of a shale reservoir as bases, the
diffusion coefficient of the gas (
methane) in shale is calculated, and the diffusion
mass-
transfer capacity of the gas (
methane) in the shale is quantitatively assessed. In the experiment testing process, the diffusion process of gas in the
shale gas reservoir can be effectively simulated, and influences of
effective stress, gas adsorption /
desorption and other factors on the diffusion coefficient are reflected. Besides, the method can overcome influences of gas
free expansion stage data in a traditional adsorption /
desorption method on the diffusion coefficient. The method can assess the diffusion
mass-
transfer capacity of the gas in the shale and provide experiment support for researches in the aspects of
shale gas reservoir productivity models, productivity prediction and the like.