南方复杂地区页岩气差异富集机理及其关键技术

针对我国南方海相富有机质页岩时空非均质强、热演化程度高、构造演化历史复杂、页岩气具差异富集和保存条件多样等特点，采用多学科方法对南方五峰组-龙马溪组海相页岩气区进行精细解剖，形成了针对南方复杂地区海相高过成熟页岩气评价参数表征的多项关键技术.研究结果显示富泥硅质页岩和富泥/硅混合质页岩是五峰组-龙马溪组的优质岩相；页岩中孔和宏孔提供了主要的孔体积，微-纳米孔隙结构特征受页岩组分及其孔隙发育程度双重控制；页岩气富集演化具二高、三复杂特点（古温度高，热演化程度高，温压演化复杂，页岩气赋存方式复杂及保存条件复杂）.研究中所提出的页岩岩相表征和优选技术、多尺度储集空间全息表征技术、海相页岩复杂演化改造过程表征技术、初步形成的甜点评价参数体系表征方法可有效地应用于南方五峰组-龙马溪组海相页岩气评价.研究成果可为南方页岩气基础地质调查工程提供技术支撑. 

Differential Enrichment Mechanism and Key Technology of Shale Gas in Complex Areas of South China

In view of the characteristics of strong temporal and spatial heterogeneity, high thermal maturity, complex tectonic evolution, differential enrichment and various preservation conditions of shale gas in southern China, multidisciplinary methods are applied to further study the Wufeng-Longmaxi marine shale gas, and a number of key technologies are developed to characterize the evaluation parameters of marine shale gas with over-high maturity in the complex geologic areas of southern China. The results show that argillaceous siliceous shales and argillaceous/siliceous mixed shales are the advantageous lithofacies in the Wufeng Formation-Longmaxi Formation. The meso-pore and macro-pore make a great contribution to the pore volume, and the micro-nano pore structure is controlled by mineral composition and porosity development. The enrichment and evolution of shale gas are characterized by high paleotemperature, high thermal evolution, complex evolution of temperature and pressure, complicated conditions for shale gas occurrence and preservation. The Wufeng-Longmaxi marine shale gas could be effectively evaluated in terms of technologies of lithofacies optimization, the characterization of pore space from macroscopic and microscopic perspectives, the complex evolution process of marine shale, and the evaluation parameters for sweet spots of shale gas. The research results can provide technical support for the basic geological survey of shale gas in southern China.