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

容积岩的孔隙度和渗透率(孔隙尺度属性)是考虑油气藏的两个重要参数。通常，这些参数决定了一个油气田的经济价值、评价方法和开发计划。尽管有大量关于特定油田/地层的孔隙尺度储集层质量控制的单独研究，但对勘探前可预测性的综述方法有限。孔隙尺度的储集层质量控制通常按两个子类进行研究，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决定了储集层的最终孔隙尺度属性。尤其在碎屑岩储层中，早期成岩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)原始孔隙水组成，因为这些因素决定了相对封闭系统中的流体流动路径和有效元素。虽然碎屑岩储层的沉积学和成岩作用得到了广泛的研究，但这两个问题往往是由不同的研究小组完全孤立地进行的。这一建议旨在用孔隙尺度数据填补大规模沉积学之间的空白，以形成对砂岩储层早期/时代的全面了解。这项研究将侧重于沿海/近海体系沉积性质的横向和纵向变化，以及在沉积过程中可能的早期成岩路径。滨海沉积环境在这里被特别选择，因为它经常与保存早期成岩绿泥石建造的孔隙度有关。为了建立微观和宏观之间的联系，计划使用两个研究区：1)美国犹他州白垩纪三角洲序列的充分暴露和深入研究；2)英国RavenGlass河口的全新世岩心。同时研究现代和古代系统还可以研究压实作用对沉积性质的影响。主要任务将包括：-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-砂岩岩石学、X射线衍射和扫描电子显微镜研究，以确定结构特性、颗粒组成、碎屑粘土类型和成岩阶段。-在拉文格拉斯河口；对孔隙水进行采样，以确定整个河口不同相组合中可能存在的原始孔隙水化学。

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.