Study of gas seepage law by considering the influence of adsorption and slippage
In order to investigate the influence of CO2 on shale permeability,the pressure pulse seepage test of CO2 was carried out by using the self-developed seepage device.The test results show that:at low pore pressure,the effect of CO2 adsorption on the permeability is greater,and with the increase of pore pressure,the effect of CO2 adsorption on the permeability decreases gradually;The permeability is fitted by the modified slippage effect seepage formula,and it is found that the modified slippage effect formula is more in line with the permeability trend.The effect of slippage effect on permeability was quantitatively analyzed by the contribution rate of slippage effect.When the pore pressure was in the range of 2.5MPa～4MPa,the slippage effect had a great influence on the permeability,and the contribution rate reached 27.78％.With the increase of pore pressure,the contribution rate gradually dropped to 8.44％.Under the condition of low pore pressure,the slippage effect is more obvious,and the slippage effect decreases exponentially with the increase of pore pressure.
shaleslip off effectpermeabilityporosityadsorption
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