论文部分内容阅读
CO2-CH4置换技术作为一种既可生产CH4又能减少CO2排放的天然气水合物开采方法,近20年来得到了广泛深入的研究。该技术的优势是:当温度低于10℃,CO2水合物较CH4水合物在热力学上更为稳定,两者的置换反应在理论上是自发的,CO2水合物的形成有助于保持气体水合物藏的地质力学稳定性。但该方法也有缺点,CH4水合物周围CO2水合物的形成限制了CH4水合物的分解,孔隙空间中形成的次生水合物会堵塞可用于气体置换的渗透性通道,因此并不是所有的CH4都能被CO2所替换。近年来业界在CO2-CH4置换技术的室内实验、数值模拟和现场试验等方面取得了一些进展。未来主要的研究方向应是全面了解不同生产策略下CO2-CH4-CH4水合物-CO2水合物-水/卤水系统的行为和储层条件;开展更多的现场规模生产项目;数值模拟中需要考虑更多的组分和相态,了解和考虑更多的过程和机理,并结合室内和现场试验结果,考虑地质特性的影响;更深入地了解CO2和N2对CH4的驱替。
As a natural gas hydrate production method that can both produce CH4 and reduce CO2 emissions, CO2-CH4 replacement technology has been extensively studied in recent 20 years. The advantage of this technique is that when the temperature is lower than 10 ° C, the CO2 hydrate is more thermodynamically stable than the CH4 hydrate, the displacement reaction of both is spontaneous, and the formation of CO2 hydrate helps to keep the gas hydrate Geomechanics stability of the collection. However, this method also has the disadvantage that the formation of CO2 hydrate around the CH4 hydrate limits the decomposition of CH4 hydrate, and that secondary hydrates formed in the pore space block the permeable channels available for gas replacement and therefore not all CH4 Can be replaced by CO2. In recent years, the industry has made some progress in the laboratory experiment, numerical simulation and field test of CO2-CH4 replacement technology. The main research directions in the future should be to fully understand the behavior and reservoir conditions of CO2-CH4-CH4 hydrate-CO2 hydrate-water / brine systems under different production strategies; to conduct more on-site production projects; and to consider in numerical simulation More components and phases, understand and consider more processes and mechanisms, consider the effects of geological characteristics in combination with indoor and field test results, and gain more insight into the displacement of CH4 by CO2 and N2.