甲烷在页岩气储层微纳米孔隙系统中运移的动力学机理研究

The dynamic mechanism of shale gas (methane) in the micro-nanometer pores is the critical factor to restrict the knowledge of the shale gas accumulation. This project is targeted to the two suits of early Paleozoic marine shale of the Cambrian Qiongzhusi Formation and Silurian Longmanxi Formation. The images of the micro-nanometer pores of the shale samples from the outcrops and cores will be acquired by the forced ion beam milling and scanning electron microscopy. The high-resolution images thereafter will be used to extract the parameters of the pores and to reconstruct three-dimensional models based on GIS. The mineralogical compositions, trace elements, kerogen and total organic carbon will be analyzed. These lithogeochemical data, combining the three-dimensional models of the pores, will be used to determined the dominances of the micro-nanometer pore development. Based on above work, the project will adopt the method of the material molecular to simulate the absorptive-diffusive molecular dynamic actions of the methane in the micro-nanometer pores. Collectively, both lithochemical and methane molecular simulative results are expected to reveal molecular dynamic mechanisms of the methane in the micro-nanometer pores，and impacts of which to methane occurrence state and recoverable reserves will also be discussed.

页岩气储层微-纳米孔隙系统中甲烷分子运移的动力学机理，是制约客观认识页岩气聚集成藏的关键因素。本项目以滇黔北地区寒武系筇组寺组、志留系龙马溪组两套早古生代海相页岩为研究对象, 基于大量野外露头和钻井岩心样品，通过聚焦离子束与场发射扫描电镜结合，获取微-纳米孔隙序列图像，利用GIS平台对高分辨率图像进行孔隙参数提取与三维孔隙模型三维重建。分析测试样品的矿物组分、微量元素、干酪根类型、总有机碳等岩石地球化学指标，并结合三维孔隙模型探讨地质作用对微-纳米孔隙发育的控制因素。在上述研究基础上，运用材料科学中分子模拟研究方法，刻画甲烷在微-纳米孔隙模型中吸附-扩散的分子动力学行为，综合两套页岩的岩石地球化学指标与甲烷分子模拟研究结果，揭示甲烷在微-纳米孔隙系统中的动力学机理，探讨其对甲烷赋存状态及最终可动用程度的影响。