How depositional properties dictate the early diagenetic pathways and reservoir quality of sandstones?

储集岩的孔隙度和渗透率（孔隙尺度属性）是评价油气藏的两个重要参数。通常，这些参数决定了油气田的经济价值、评估方法和开发计划。尽管有大量关于特定油田/地层的孔隙尺度储层质量控制的个别研究，但对勘探前可预测性的总体方法是有限的。孔隙尺度储层质量控制通常分为两个子类别，即（i）沉积控制和（ii）成岩控制，然而，在大多数情况下，这两个因素共同作用以确定储层的最终孔隙尺度属性。特别是在碎屑岩储层中，早期成岩作用路径与沉积性质密切相关，包括1）结构（粒度、分选和碎屑粘土含量），2）碎屑成分（包括碎屑粘土类型），3）组构（沉积构造）和4）原始孔隙水成分，因为这些因素决定了相对封闭系统中的流体流动路径和可用元素。尽管碎屑岩储层的沉积学和成岩作用已被广泛研究，但这两个课题往往被完全孤立地交给不同的研究小组。该建议旨在填补大规模沉积学与孔隙尺度数据之间的差距，以便形成对砂岩储层早期/时期的完整理解。这项研究将侧重于海岸/沉积系统沉积特性的横向和纵向变化以及沉积过程中可能的早期成岩途径。海岸沉积环境在这里有特别的选择，因为它通常与保存早期成岩作用的孔隙有关。计划使用两个研究区域，以形成微观和宏观世界之间的联系; 1）犹他州（美国）的白垩纪三角洲序列暴露良好，研究深入; 2）Ravenglass河口（英国）的全新世岩心。同时研究现代和古代系统还可以研究压实作用对沉积特性的影响。主要任务包括：- 实地工作，为研究建立沉积学背景，包括岩心和露头测井、对比、过程解释和取样-砂岩岩相学、XRD和SEM研究，以确定结构特性、颗粒成分、碎屑粘土类型和成岩阶段。- 在Ravenglass河口;孔隙水取样，以确定整个河口各种相组合中可能的原始孔隙水化学。

The porosity and permeability (pore-scale attributes) of a host rock are the two important parameters for a consideration of a hydrocarbon reservoir. Often, these parameters determine the economic value, appraisal approaches and development plans for a hydrocarbon field. Although there are vast amount of individual studies on pore-scale reservoir quality controls of particular fields/formations, overview approaches towards the pre-exploration predictability is limited. The pore-scale reservoir quality controls are typically investigated in two sub categories as (i) depositional and (ii) diagenetic controls, however, in most cases, these two factors act together to determine the final pore-scale attributes of a reservoir. Particularly in the clastic reservoirs, early diagenetic pathways are strongly linked to the depositional properties including 1) texture (grain-size, sorting and detrital clay content), 2) detrital composition (including detrital clay types), 3) fabric (sedimentary structures) and 4) original pore water composition, as these factors determine the fluid flow pathways and available elements in the relatively closed system. Although the sedimentology and diagenesis of clastic reservoirs and widely studied, these two topics are often handed in complete isolation with different research groups. This proposal aims fill the gap between large-scale sedimentology with pore-scale data in order to form a complete understanding of early days/times of a sandstone reservoir. The study will focus on the lateral and vertical variations of the depositional properties of coastal/paralic systems and possible early diagenetic pathways in the context of sedimentary processes. The coastal depositional setting have particularly selected here, as it is often linked to the porosity preserving early diagenetic chlorite formation. Two study areas are planned to be used in order to form the link between micro and macro-word; 1) well-exposed and intensely-studied Cretaceous deltaic successions in Utah (USA), and 2) Holocene cores from Ravenglass Estuary (UK). Studying the modern and ancient systems together will additionally allow to investigate the effects of compaction on depositional properties. Main tasks will include;- Field work to build the sedimentological background for the study, including core and outcrop logging, correlation, process interpretation and sampling - Sandstone petrography, XRD and SEM studies to define textural properties, grain composition, detrital clay types and diagenetic phases. - In Ravenglass Estuary; pore water sampling in order to characterise possible original pore-water chemistry in various facies associations throughout the estuary.