多场耦合条件下甲烷/二氧化碳在页岩非均质储层中的动力学特征研究

Under buried circumstance, they have not been figured out that the movement process of CH4 and CO2 in shale reservoirs and the mechanism CO2 displaces CH4 efficiently and been storaged in shale reservoirs , which are as the urgent problems to be solved. This project aims to build the relationship among micropores, mineral composition, sedimentation and diagenesis by getting the data on filed, drilling, testing, obtaining mineral composition, chemical characters, trace elements, clay minerals, type of kerogens and thermal evolution extent. On the basis of SEM, OFM and indirect measurement of shale microspace, furthermore, three-dimension modeling will realize by multi-scale qualitative and quantitative characterization about heterogeneity system of shale micropore. It is vital to comprehensively analyze multiple field factors that include tenperature and pressure to the features of anisotropic pore system in shale and the influence on the dynamic characteristics of CH4 and CO2 in shale. Monte Carlo, molecular mechanics and molecular dynamics methods will be used to simulate movement process of CH4 and CO2 in shale pore system under buried circumstance, to explore mutual coupling relations between CH4 and the mechanism CO2 displaces CH4 efficiently and been storaged in shale reservoirs.

埋藏条件下CH4和CO2在页岩储层中的运动过程及CO2置换CH4并封存的机理是当前页岩气研究中亟待解决的问题。本项目拟以四川盆地南部五峰组和龙马溪组页岩气储层为对象，通过野外和钻井取样、测试，获取页岩的矿物组分、化学组成、微量元素、粘土矿物、干酪根类型及其热演化程度等数据，建立页岩微观孔隙发育与矿物成分、沉积、成岩作用之间的关系。通过扫描电镜、原子力显微镜的直接观察与对页岩微观储集空间的间接定量测定，实现对页岩非均质微观孔隙系统的多尺度定量和定性表征并进行三维建模。综合分析埋藏条件下多场因素对页岩非均质微观孔隙系统发育特征及对其中的CH4和CO2运动力学特征的影响，利用蒙特卡洛方法、分子力学、分子动力学方法等模拟埋藏条件下CH4和CO2在页岩非均质微观孔隙系统中的运动行为，探讨页岩非均质微观孔隙系统中CH4和CO2气体的运动与微观孔隙系统之间的耦合关系及CO2置换CH4并封存的机理。

本项目在页岩样品矿物组分、化学组成、微量元素、粘土矿物、干酪根类型及其热演化程度等数据分析的基础上，分析了页岩微观孔隙发育与矿物成分、沉积环境、成岩作用等之间的关系，构建了页岩储层纳米孔隙表征模型，利用蒙特卡洛方法、分子力学、分子动力学方法等模拟埋藏条件下CH4和CO2在页岩非均质微观孔隙系统中的运动行为，探讨了页岩非均质微观孔隙系统中CH4和CO2气体分子竞争性吸附-解吸-扩散-渗流与非均质微观孔隙系统之间的相互耦合关系以及流体在页岩非均质微观孔隙系统中的运动行为。并且，在高阶煤纳米级孔隙结构特征及甲烷吸附性等方面也取得了明显的进展。研究成果将对我国页岩气勘探开发的理论与技术突破具有积极意义。