基于CO2置换法的海洋天然气水合物开采技术具有广阔应用前景，可以同时实现能源开采、温室气体封存及海底地质修复，其中一个关键科学问题就是置换产生的气泡表面水合物二次生成及CO2-CH4置换反应机理。本项目拟开发一套基于悬浮气泡法及原位拉曼观测法的水合物研究装置， 用于 ① 建立水中悬浮气泡表面水合物横向生长和增厚生长过程中的膜厚度拉曼测量方法，研究膜增厚过程中的膜形态、传质阻力及动力学控制因素；② 揭示气-液水合物膜的多界面接触过程中双向传质对膜增厚过程的影响机理；③揭示气态与液态CO2分别在水平膜和弯曲膜内的扩散和置换机理。本项目创新点在于将原位拉曼方法与水合物三维形态相关联，通过定量分析微观形态和分子质量传递来揭示CO2-CH4水合物生成和置换机理，为CO2置换开采水合物提供理论支持。

CH4–CO2 replacement for gas hydrate exploration holds broad application prospects by providing a means for methane recovery, long-term storage of CO2, and submarine geologic restoration. For CH4–CO2 replacement exploration, one of the key scientific problems is the hydrate secondary growth at the surface of bubble and CO2-CH4 clathrate hydrate replacement mechanism. In this project, a novel research apparatus will be designed to study hydrate growth and CO2-CH4 clathrate hydrate replacement reaction by exposing a single gas bubble to water. The measurement methods include in-situ Raman, confocal microscope and optical microscope. The main research contents are:(1)establishing a new method of hydrate film thickness measurement by Raman spectra and investigating film morphology, mass transfer resistance and kinetic control factors;(2) establishing the multi-interfaces growth mechanism of hydrate films; (3)studying gas and liquid CO2 diffusion and displacement mechanism in planar and curved films respectively; The innovation of this project is to associate the in-situ Raman method with the three-dimensional hydrate morphology. The CO2-CH4 hydrate growth and replacement mechanism was revealed by quantitative analysis of microscopic morphology and molecular mass transfer providing theoretical support for CH4 hydrate recovery using CO2.