致密砂岩储层中黏土矿物发育特征及其生长机理研究进展

Advances in Studies of Development and Growth Mechanisms of Clay Minerals in Tight Sandstone Reservoirs

[目的]沉积岩中广泛发育的黏土矿物贯穿构造—沉积—成岩整个地质过程,记录了全盆地、多尺度的水—岩—烃相互作用信息。针对砂岩储层中黏土矿物的形成、生长和转化过程进行系统调研,不仅对健全成岩作用体系研究具有重要的学术探索意义,也从孔喉结构演变和物性响应角度为致密砂岩油气勘探、开发提供有力支撑。[方法]围绕这一主旨,详述了蒙脱石、高岭石、伊利石、绿泥石和混合晶层黏土矿物的基本特征、物质基础与生长环境,在归纳前人经典认识和最新进展的基础上梳理关键科学问题和前沿研究热点。[结果]黏土矿物与母岩性质、沉积微相之间空间耦合特征明显;黏土矿物内层包膜形成过程中可能存在机械渗滤和生物诱导两种机理,有待后续研究进一步明确;在成岩环境主导下,黏土矿物外层包膜的生长与其他流―岩作用的发生存在物质依赖和空间竞争关系,并反向影响介质条件。在含油气盆地中,黏土矿物通过改变孔喉结构和成岩进程对储层品质表现出绝对消极和相对积极的“双刃剑”作用;利用原位微区分析技术精准揭示多尺度的黏土矿物生长过程和控储作用,既满足油气勘探开发的现实需求,又推动了盆地流体—岩石相互作用的发展。[结论]技术创新驱动储层地质学认识不断深化,并在实际勘探工作中逐渐完善,为实现油气增储上产提供理论基础。

[Objective]The widely developed clay minerals found in sedimentary rocks are links to the whole geologi-cal process of tectonism,sedimentation and diagenesis,and they record information about the water-rock-hydrocarbon interactions on many different scales over the entire sedimentary basin.Systematic investigation of the formation,growth and transformation of clay minerals in sandstone reservoirs is of important academic significance regarding the completion of the diagenetic framework,and it also strongly supports reservoir exploration and development in tight sandstones from the perspective of pore-throat evolution and pore-permeability response.[Methods]Focusing on this theme,the basic characteristics,material bases and growth environments of montmorillonite,kaolinite,illite,chlo-rite and other mixed-layer clay minerals are discussed in detail.This summary of previous classical views and recent findings enables the key issues to be categorized.[Results]The results show that there is an obvious spatial coupling relationship between clay minerals,parent rocks and sedimentary microfacies.Mechanical percolation and biological induction mechanisms may have existed in forming internal clay coating,and these are topics for follow-up research.The diagenetic environment dominates the growth of the outer clay coating;other geological fluid-rock interactions are related by material dependence and competition for space,and have the opposite effect on the fluid medium.In petroliferous basins,the effect of clay minerals on reservoir quality may range from absolutely negative to relatively positive,depending on the pore-throat structure and diagenetic process.Microzone in-situ analysis technology was used to accurately reveal the growth process of clay minerals and its effect on reservoirs at the whole-basin scale,thus meeting the realistic demand of petroleum exploration and development and also emphasizing the importance of geo-logical fluid-rock interaction studies.[Conclusion]Technical innovation has resulted in a deeper geological under-standing,and its application has gradually improved practical exploration as well as providing a sound theoretical basis for increasing petroleum storage and production.