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为了研究天然气水合物开采过程中水合物饱和度和有效应力变化对含水合物沉积层渗透率变化规律的影响,利用自主研制的水合物沉积物合成与三轴渗流实验一体化装置,进行了有效应力升降过程中不同饱和度水合物沉积物渗透性实验。结果表明:有效应力升降过程中,不同饱和度水合物沉积物的渗透率与有效应力均呈负指数规律变化,并表现出在低有效应力阶段渗透率变化的幅度大于高有效应力阶段;有效应力升降过程中,试样产生的不可恢复变形使渗透率不能完全恢复,造成渗透率永久损失;有效应力不变时,水合物沉积物的渗透率与水合物饱和度呈负指数规律变化,且曲线的斜率随饱和度增加由大变小;水合物的饱和度越大,最大渗透率损害率越大,渗透率恢复的程度越差。
In order to study the influence of hydrate saturation and effective stress on the variation of permeability of hydrate-bearing sediments during the process of gas hydrate mining, an integrated experimental device for hydration sediments synthesis and triaxial seepage experiment was developed. Experimental study on permeability of hydrate sediments with different saturation during the process of stress. The results show that the permeability and effective stress of hydrate deposits with different degrees of saturation change negatively exponentially during the process of effective stress rise and fall, and show that the permeability change rate in low effective stress stage is larger than that in high effective stress stage. The effective stress In the process of ascending and descending, the irreversible deformation caused by the specimen can not completely recover the permeability, resulting in the permanent loss of permeability. When the effective stress is constant, the permeability and hydrate saturation of hydrate sediments change negative exponentially, and the curve The slope of the permeability decreases from large to small. The higher the saturation of hydrate, the greater the damage rate of maximum permeability and the worse the permeability recovery.