Abstract Absolute and water saturation dependent gas flow under reservoir conditions is important for the exploration of deep energy resources. Steady-state and various unsteady-state argon permeability tests were conducted on dry Niutitang shale during the confinement loading and unloading cycles, then different gases were used for steady-state permeability tests at the final confinement of 20 MPa. Permeability decreased by 36% with the confinement increasing from 5 MPa to 60 MPa, and around 66% of the permeability reductions was recovered after the unloading cycles. The apparent steady-state permeabilities were 38% higher than those derived by unsteady-state methods due to the enhanced slip flow. Two cycles of water imbibition and gas drainage tests were conducted with the long water evaporation process completed in the second gas drainage process. Argon to carbon dioxide permeability ratio ranged from 1.2 to 2.1, while the water permeability was 30–45% of the gas intrinsic permeability. The argon breakthrough pressure of water-saturated Niutitang shale sample was 8 MPa, and the permeability increased by 10 times after the long-term evaporation process. Argon permeability decreased by 90% and increased by 21.6%–29.6% respectively after the first and second gas drainage processes compared with that under dry condition with the residual water saturation being 29.7% and 11.3% respectively, which were caused by the water blockage and cracking respectively. Influences of carbon dioxide adsorption and induced swelling reached a minimum at residual water saturation.

中文翻译：

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储层条件下牛蹄塘页岩流动特性的室内评价

摘要 储层条件下绝对和含水饱和度相关的气流对于深部能源资源的勘探具有重要意义。对干牛蹄塘页岩在约束装卸循环过程中进行了稳态和各种非稳态氩气渗透率测试，然后在20 MPa的最终约束条件下使用不同气体进行稳态渗透率测试。随着约束从 5 MPa 增加到 60 MPa，渗透率下降了 36%，并且在卸载循环后恢复了大约 66% 的渗透率下降。由于滑流增强，表观稳态渗透率比非稳态方法得出的渗透率高 38%。二次抽气过程完成了长水蒸发过程，进行了两次吸水和抽气试验。氩气与二氧化碳的渗透率比范围为 1.2 到 2.1，而水渗透率为气体固有渗透率的 30-45%。饱和水牛蹄塘页岩样品的氩气突破压力为8 MPa，经过长期蒸发过程，渗透率增加了10倍。与干燥条件相比，第一次抽采和第二次抽采后氩气渗透率分别下降 90% 和 21.6%～29.6%，残余水饱和度分别为 29.7% 和 11.3%。分别开裂。