天然气水合物二次生成是制约其安全、高效开采的重大课题。本项目以解明天然气水合物分解过程沉积层内热质传递特性和水合物二次生成机理为目标，开发水合物分解沉积层温度、压力和渗透特性跟踪测试平台和数值模拟方法，测试水合物分解吸热过程对沉积层温度分布的影响，建立沉积层内水合物分解吸热、介质传热、水合物二次生成放热之间的动态平衡方程；解明分解过程沉积层压力、骨架结构和渗透特性变化规律，确定混气液体渗流对天然气水合物分解与二次生成的影响机理；分析水合物二次生成对沉积层内骨架结构、渗流特性和压力分布的反作用，解明渗流过程热质传递与水合物二次生成的相互影响机制；开发天然气水合物开采沉积层内含相变（水合物分解与二次生成）和多相渗流过程的热质平衡与传递方程，以经典水合物热力学和动力学理论为基础，建立耦合相平衡、生成诱导时间和生长动力学的开采沉积层内天然气水合物二次生成预测模型，为天然气水合物开采提供理论支持。

Hydrate reformation is a major restriction for the safe and efficient natural gas hydrate exploitation. The purpose of this project is to interpret the characters of heat and mass transfer, and the mechanism of gas hydrate reformation during natural gas hydrate dissociation. We intend to develop a tracking experimental platform and a numerical simulation method for the measurement and calculation of hydrate reservoir temperature, pressure and permeability characteristics during natural gas hydrate dissociation. To establish the dynamic balance equation between endothermic hydrate decomposition, heat transfer and exothermic hydrate reformation, we will measure and reveal the influence of endothermic hydrate dissociation on temperature distribution in sediment. The change rule of pressure, sediment frame and permeability characteristics also needs to be interpreted, and finally we will conclude the influence of aerated liquid seepage on gas hydrate dissociation and reformation. The retroaction of gas hydrate reformation on sediment frame, permeability characteristics and pressure distribution in the sediment layer are also analyzed to interpret the interaction of heat and mass transfer with hydrate reformation during the seepage process. We also plan to establish the heat and mass transfer equation for natural gas hydrate dissociation process in sediment, which includes phase change (hydrate dissociation and reformation) and multiple-phase seepage. The hydrate reformation model for natural gas hydrate exploitation process is coupling of hydrate phase equilibrium, hydrate formation induction time and hydrate growth dynamics model. It will provide some basic data and fundamental for natural gas hydrate exploitation.