The pulse-decay technique is a well-established laboratory method for measuring the permeability of hydraulically tight rocks. Nitrogen or helium is routinely used in measurement of pulse-decay method, but the main components of natural gas reservoirs are hydrocarbons such as methane. In addition, nitrogen or helium has greater access to the fine pore structure of shale than larger molecules such as methane. Utilizing gas such as methane other than N2 or He to measure permeabilities requires corrections for gas rarefaction effect to be incorporated in the analyses. Knudsen number (Kn), the ratio between the gas free molecule distance and the pore diameter, is one of the key parameters to evaluate the rarefaction effect on the transport mechanism in micro/nano channels or porous media structure. When 0.001展开▼
机译：The pulse-decay technique is a well-established laboratory method for measuring the permeability of hydraulically tight rocks. Nitrogen or helium is routinely used in measurement of pulse-decay method, but the main components of natural gas reservoirs are hydrocarbons such as methane. In addition, nitrogen or helium has greater access to the fine pore structure of shale than larger molecules such as methane. Utilizing gas such as methane other than N2 or He to measure permeabilities requires corrections for gas rarefaction effect to be incorporated in the analyses. Knudsen number (Kn), the ratio between the gas free molecule distance and the pore diameter, is one of the key parameters to evaluate the rarefaction effect on the transport mechanism in micro/nano channels or porous media structure. When 0.001展开▼
