Recurrent mass transport deposits (MTD) not only act as competent seals trapping fluids, but their basal shear zones connected by pipes also serve as potential reservoirs for gas hydrate within the gas hydrate stability zone. However, this has seldom been addressed in previous studies. Using conventional 3D seismic reflection data and well data collected from the Central Canyon area of the northwestern South China Sea, we find that gas hydrates mainly lie in the fractures within MTDs. These fractures can be subdivided into two groups. The first group is composed of the horizontal and low-angle oblique fractures characterized by pseudo-SC structures, the majority of which occurred within the basal shear zones of MTDs. They probably resulted from the strong shear stresses during mass transport. The second group comprises the nearly vertical fractures within pipes 1 and 2. They are attributed to the result of hydraulic fracturing during the generation of pipes. It is important to note that the basal shear zones of MTDs 2–4 were connected by the pipes in the vertical direction and have good lateral continuities (with the area of hundreds of km²), and thus they probably provide larger reservoir spaces for gas hydrates, compared with the hydraulic fractures merely confined within pipes 1 and 2 (with the area less than 1 km²). Therefore, in the future gas hydrate exploration, much more attention should be paid to basal shear zones of recurrent MTDs that are connected by pipes in the vertical direction. Hydrocarbon gas that formed gas hydrates with water molecular, were mainly supplied by three large-scale gas chimneys above the basement highs. We suggest that the single overpressure configuration and effective seals provided by the deep-seated MTD1 were responsible for the continuous gas accumulations above the basement highs. Hence, hydraulic fracturing took place and these gas chimneys were formed. We also propose a 3D conceptual model to show how MTDs influence fluid migration and accumulation, and prevent methane seepages.

循环传质沉积物 (MTD) 不仅可以作为有效的密封圈来捕获流体，而且它们通过管道连接的基底剪切带还可以作为天然气水合物稳定带内天然气水合物的潜在储层。然而，这在以前的研究中很少被提及。利用南海西北部中央峡谷地区常规3维地震反射资料和井资料，发现天然气水合物主要分布在MTD内的裂缝中。这些骨折可以细分为两组。第一组由以伪SC结构为特征的水平和低角度斜裂缝组成，其中大部分发生在MTD的基底剪切带内。它们可能是由于大规模运输过程中的强剪应力造成的。第二组包括管道 1 和 2 内几乎垂直的裂缝。它们归因于管道生成过程中水力压裂的结果。值得注意的是，MTD 2-4 的基底剪切带在垂直方向上由管道连接，并且具有良好的横向连续性（面积为数百公里）² )，因此与仅限制在管道 1 和 2 内（面积小于 1 km ²）。因此，在未来的天然气水合物勘探中，应更加关注垂直方向通过管道连接的复发性MTD的基底剪切带。与水分子形成天然气水合物的烃类气主要由基底高位上方的三个大型气烟囱供应。我们认为，深层 MTD1 提供的单一超压配置和有效密封是造成基底高点上方连续天然气聚集的原因。因此，发生了水力压裂并形成了这些气烟囱。我们还提出了一个 3D 概念模型来展示 MTD 如何影响流体迁移和聚集，并防止甲烷渗漏。