The benefits of large reserves, wide distribution, and high combustion energy density of natural gas hydrates are of great practical importance to alleviate the energy tension, enhance the existing energy system in China and reduce the greenhouse effect. The CO₂ replacement method is a critical way to develop natural gas hydrate, while traditional experimental methods are difficult to reveal the microscopic mechanism of the replacement system. An MD (molecular dynamics) technique was utilized in this work to simulate the process of carbon dioxide replacement of gas hydrates. This simulation investigates the effects of temperature, pressure, and CO₂ purity during the CO₂ replacement process. CO₂, different concentrations of CO₂/H₂O, and CO₂/NH₃ are used as the injected fluid. The simulation results show that the influence of temperature on the CO₂ replacement of natural gas hydrate is more significant than that of pressure. Within the temperature and pressure range specified in the simulation, H₂O inhibits the replacement of CO₂, owing to the inhibitory effect increasing as the concentration of H₂O increases; NH₃ promotes the process of CO₂ replacement under the temperature conditions of 250 K and 260 K, and the promotion effect becomes more significant as the concentration of NH₃ increases. However, adding NH₃ inhibits the CO₂ replacement process with hydrate when the temperature lifts to 270 K. These findings provide new ideas to improve the efficiency of the CO₂ replacement method and provide theoretical insight for the engineering exploitation of hydrates.

天然气水合物储量大、分布广、燃烧能量密度高等优点，对于缓解能源紧张、提升我国现有能源体系、降低温室效应具有重要的现实意义。CO ₂置换法是开发天然气水合物的关键途径，而传统的实验方法难以揭示置换体系的微观机理。这项工作采用 MD（分子动力学）技术来模拟二氧化碳置换天然气水合物的过程。_{该模拟研究了 CO 2置换过程中温度、压力和 CO 2}纯度的影响。CO ₂、不同浓度的CO₂ /H ₂ O和CO ₂ /NH ₃用作注入流体。模拟结果表明，温度对天然气水合物CO _{2置换的影响比压力更显着。}在模拟规定的温度和压力范围内，H _{2 O抑制CO 2}的置换，抑制作用随着H ₂ O浓度的增加而增加；NH _{3在250 K和260 K温度条件下促进CO 2}置换过程，且随着NH ₃浓度的增加，促进作用更加显着增加。然而，当温度升至270 K时，添加NH ₃会抑制水合物对CO _{2 的置换过程。这些发现为提高CO 2}置换方法的效率提供了新思路，并为水合物的工程开发提供了理论依据。