New Method of Assessing Absolute Permeability of Natural Methane Hydrate Sediments by Microfocus X-ray Computed Tomography
New Method of Assessing Absolute Permeability of Natural Methane Hydrate Sediments by Microfocus X-ray Computed Tomography
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DOI：
10.1143/jjap.46.3159
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发表时间：
2007-05
影响因子：
1.5
通讯作者：
Yusuke Jin;J. Hayashi;J. Nagao;Kiyofumi Suzuki;H. Minagawa;T. Ebinuma;H. Narita
中科院分区：
文献类型：
--
作者：
Yusuke Jin;J. Hayashi;J. Nagao;Kiyofumi Suzuki;H. Minagawa;T. Ebinuma;H. Narita
利用微焦点X射线计算机层析成像（CT）系统研究了天然气水合物沉积物的结构。从获得的三维（3-D）图像中识别出自由气体空间、砂粒和水合物或冰。我们使用CT数据来分析一个连续的孔隙，它允许气体和水流动。沉积物样品的绝对渗透率与水平通道密度在方向上具有良好的相关性。沉积物样品中的粒度分布取决于流动通道的扩展。河道的平均面积和长度对绝对渗透率的影响很小。我们确定，绝对渗透率增加的比例，水平到垂直通道数。很明显，在相似的孔隙度范围内，水平通道与垂直通道的数量比是决定绝对渗透率的主要因素。这些结果表明，孔隙网络在沉积物中可以用于评估渗透率。
The structure of natural-gas hydrate sediments was studied using a microfocus X-ray computed-tomography (CT) system. The free-gas spaces, sand particles, and hydrates or ices were identified from the obtained three-dimensional (3-D) images. We used CT data to analyze a continuous pore, which allows gas and water flow. The absolute permeability of sediment samples correlated well with horizontal-channel density in terms of direction. The grain-size distribution in sediment samples depended on the spread of flow channels. The average area and length of a channel evidently have little effect on absolute permeability. We determined that absolute permeability increased with the ratio of horizontal- to vertical-channel numbers. It was clear that the number ratio of the horizontal to vertical channels is a predominant factor that determines absolute permeability in similar porosity ranges. These results indicate that the pore network in sediments can be useful for assessing permeability.