论海相页岩气富集机理——以四川盆地五峰组—龙马溪组为例

深入探究页岩气富集机理是保障勘探开发高效推进的基础。本研究通过对四川盆地五峰组—龙马溪组页岩气勘探开发实践的系统分析，梳理总结前人研究成果，从生成机理、运移机理、赋存机理和保存机理四个方面对海相页岩气富集机理进行了深入分析，并讨论了深层和常压页岩气的勘探开发潜力。结果表明：在生成机理方面，埋藏史和热演化史控制了页岩生排烃史、生排烃量和现今含气量；页岩气运移机理涉及运移动力、运移相态、运移方式和运移通道四方面内容，页岩气运移主要是烃源岩内的初次运移，同时讨论了初次运移的影响因素；在赋存机理方面，甲烷—页岩间表现出单/多分子层吸附和微孔充填等多种赋存机制，组分润湿性和孔隙有效性是决定甲烷吸附赋存和解吸运移的关键；在保存机理方面，盖层和物性自封闭是主要的保存机理，构造运动引起的裂缝—流体活动是页岩气保存条件遭到破坏的主要原因，流体活动时间和期次研究是页岩气保存条件和含气量定量评价的重要内容。页岩气富集机理的系统分析和创新认识为页岩气勘探开发评价提供了重要依据，建议加强页岩气演化历史全过程的动态评价。结合深层和常压页岩气勘探实践，分析了深层和常压页岩气的成因机制及主要特征，指出了下一步攻关内容及勘探方向。

Enrichment mechanism of marine shale gas—A case study of the Wufeng Formation- Longmaxi Formation in the Sichuan basin, SW China

An in- depth investigation of the shale gas enrichment mechanism is the basis for guaranteeing efficient exploration and development. Through a systematic analysis of shale gas exploration and development practices in the Wufeng Formation- Longmaxi Formation of the Sichuan basin, we have summarized previous research results and conducted an in- depth analysis of the shale gas enrichment mechanism from four aspects: generation mechanism, migration mechanism, occurrence mechanism, and preservation mechanism. Additionally, we have discussed the potential for exploration and development of deep and normal- pressure shale gas. The results show that, in terms of generation mechanism, the burial history and thermal evolution history control the generation and expulsion history of hydrocarbons, the expulsion amount, and the current gas content in shale. The migration mechanism of shale gas involves four aspects: migration dynamics, migration phase, migration mode, and migration pathway. Shale gas migration mainly presents the initial migration within the source rock, and the influencing factors of the initial migration were discussed. For the occurrence mechanism of shale gas, the interaction force between methane and shale exhibits a multi- molecular layer adsorption and microporous filling phenomenon. The component wettability and pore effectiveness are the key factors determining the adsorption occurrence and desorption migration of methane. Regarding the preservation mechanism of shale gas, the main preservation mechanism is the cap rock and self- sealing of reservoir properties, while the fracture- fluid activity caused by tectonic movement is the main reason for the destruction of shale gas preservation conditions. The study of the timing and duration of fluid activity is an important part of the quantitative evaluation of shale gas preservation conditions and gas content. The systematic analysis and innovative understanding of the shale gas enrichment mechanism provide an important basis for shale gas exploration and development evaluation. Combined with the practice of shale gas exploration, we analyzed the genesis mechanism and main characteristics of deep and normal- pressure shale gas and pointed out the next step of the research content and exploration direction.