The present work deals with an experimental investigation on methane hydrate and carbon dioxide hydrate formation in presence of two different types of sand, which acted as seabed simulators. The first typology of sand consists in pure quartz and is commonly used for laboratory experiments on gas hydrate. The other type is named TS-2 and originated from the Tunisian seabed of the Mediterranean Sea. It is silica-based (≈99%), however it also contains other elements and its grains have different shape, size and porosity. Experiments were carried out in order to verify if the specific characteristic of the seabed, in which the hydrate reservoir is present, may intervene or not on the CO₂/CH₄ replacement process and if such contribution may improve or reduce the process efficiency. Results proved that physical and chemical properties of materials which composed the seabed, may strongly intervene on the replacement process. In particular, experiments revealed that sand TS-2 acted as kinetic and thermodynamic inhibitor for methane hydrate formation, while it promoted CO₂ hydrate formation under the kinetic point of view. In this sense, sand TS-2 represents a strong ally for improving the replacement efficiency, due to its capability to both improving the kinetic of the process and reducing the methane hydrate re-formation phenomena. The present study revealed that, with a simple analysis of properties of sediments containing hydrate reservoirs, it would be possible to establish the convenience of intervening with a replacement strategy instead of a classical application for simple methane recovery.

目前的工作涉及在两种不同类型的沙子存在下甲烷水合物和二氧化碳水合物形成的实验研究，这些沙子充当海底模拟器。第一种类型的砂由纯石英组成，通常用于天然气水合物的实验室实验。另一种被命名为TS-2，起源于地中海的突尼斯海床。它是基于二氧化硅的 (≈99%)，但它也包含其他元素，其颗粒具有不同的形状、大小和孔隙率。进行了实验以验证存在水合物储层的海床的特定特征是否可以干预 CO ₂ /CH ₄更换过程，如果这种贡献可能会提高或降低过程效率。结果证明，构成海床的物质的物理和化学性质可能强烈地干预置换过程。特别是，实验表明沙子 TS-2 作为甲烷水合物形成的动力学和热力学抑制剂，同时它促进了 CO ₂动力学观点下的水合物形成。从这个意义上说，砂 TS-2 代表了提高置换效率的有力盟友，因为它能够改善过程动力学并减少甲烷水合物再形成现象。目前的研究表明，通过对含有水合物储层的沉积物的性质进行简单分析，有可能建立替代策略进行干预的便利性，而不是简单的甲烷回收的经典应用。