页岩流变构造与纳米油气

Shale rheology is an important aspect to study the structural deformation style and its mechanism in the shallow upper lithosphere. While the oil and gas in the shale nano-pore system is coming to be the key targets for non-conventional petroleum exploration. China has great potential of shale oil and gas, to explore its accumulation mechanism is going to bring forward an important basis for its exploration and development. To choose the typical shale gas exploration blocks in the South Sichuan Basin as the field study area, and utilize the data from the cores, outcrops, well logging, and seismic profiles, the proposal uses systematically the methodology of geology, rock mechanics, and multi-media physical chemistry to study the shale mega-and micro-structures of natural rheology. By disclosing the deformation behavior of shale in the series of geodynamic processes such as burial, compaction, diagenesis, and modification or uplifting in the later period, to discuss the detachment structural deformation under the radical transition of multiple periods of tectonic settings. By carrying out the shale rock mechanical experiment and observation under high-resolution microscopes, to explore the condition for brittle-to-ductile conversion, the rheological behavior and mechanisms, to discover the exhibition of shale deformation on a supra-micro-scale (i.e. nano-meter), and to study the rheological processes and its controlling factors, and finally to establish shale rheological models. By analyzing the influences of such processes on nano-pore texture and its evolution, the proposal discusses the accumulation and preservation of oil and gas in the nano-pore and fracture systems and will give a foundation for developping the theory of shale nano-oil and gas geology.

页岩流变是揭示岩石圈浅表构造变形样式与形成机制的重要内容；页岩纳米级孔隙系统中的油气逐渐成为非常规油气勘探的主要领域，我国页岩油、页岩气资源丰富，探讨页岩油气的聚集机理将为其勘探开发提供重要理论基础。本项申请系统应用地质学、岩石力学和多相介质物理化学的方法，综合使用钻孔岩心、野外露头、测井与地震等资料，选择川南页岩气勘探示范区为野外实验基地，通过系统剖析天然页岩流变的宏观与微观构造特点，研究页岩在埋藏、压实、成岩、后期改造或隆升等一系列地球动力学过程中的变形行为，揭示页岩在多期构造变革中滑脱构造变形特点；通过岩石力学试验与显微观察，研究页岩脆韧性转化条件以及流变行为和机理，探讨页岩变形在超微尺度上（纳米级）的表现，剖析流变过程及其控制因素，建立页岩流变模型；探讨页岩流变对纳米级孔隙结构及其演化的影响，分析页岩纳米级孔隙－裂缝系统中油气的聚集与保存机理，为发展页岩纳米油气地质理论奠立基础。

页岩流变是揭示岩石圈浅表构造变形样式与形成机制的重要内容；页岩纳米级孔隙系统中的油气逐渐成为非常规油气勘探的主要领域，我国页岩油、页岩气资源丰富，探讨页岩油气的聚集机理将为其勘探开发提供重要理论基础。.本项目主要研究：天然页岩流变的宏观与显微构造特征；页岩的岩石力学性质与页岩流变模型；页岩流变的高温高压实验与流变机制；页岩流变对孔隙结构与孔－缝系统的影响。.本项目以川东这一我国下古生界页岩气勘探开发示范区为实验场地。采用野外考察、岩心观察，结合井震资料，借助X衍射、薄片、扫描电镜、氩离子抛光-场发射电镜、孔隙度和渗透率测试，开展页岩流变构造与孔隙形态研究。主要取得以下认识：（1）川东地区发生分层滑脱变形，滑脱层为嘉陵江组滑脱层、下志留统龙马溪组泥岩、龙王庙组膏盐及基底滑脱层。构造变形经历晚侏罗世-古近纪早期和古近纪中晚期-至今2个阶段；（2）下寒武统水井沱组页岩主要为灰黑色含泥灰岩、泥岩，石英等脆性矿物的含量较高，粘土矿物较少。下志留统以灰黑色泥岩、炭质泥岩、粉砂质泥岩为主，石英含量相对较少，粘土矿物较多；（3）页岩流变样式主要为流变褶曲与微裂缝。同一地区深部的流变强度通常大于浅部；不同地区同一层位（如龙马溪组），流变强度总体上由东向西递减。脆性矿物含量越高，裂缝越发育；埋深大，构造应力大，流变强度较大。在脆性或流变强度较低的情况下，微裂缝发育；随流变强度增加，流变主要以褶曲揉皱为主，且褶曲强度随之增大；（4）水井沱组和龙马溪组页岩均发育多种孔隙类型。有机质孔隙和粘土矿物孔占主导，总孔隙度随流变强度的增大而减小，两者呈负相关关系。有机质孔、粘土矿物孔等塑性孔，易受流变的影响发生形态变化。随着温压的变化、埋深、构造应力的影响，页岩流变强度逐渐增大，同时纳米孔隙由不规则的近圆形大孔，逐渐转变为具定向性分布的扁平状中孔，最终形成较圆的微孔甚至消失。. 项目发表文章3篇，培养硕士生1人。在读研究生3人。