Controls on temporal & spatial distribution of organic matter in siliciclastic mudstones: implications for source rock development in Shale Gas plays

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• 批准号: NE/F013809/1
• 金额: $ 8.61万
• 依托单位: University of Leicester
• 依托单位国家: 英国
• 项目类别: Training Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FF013809%2F1
• 关键词: Controls; temporal; spatial; distribution; organic

This PhD is an exciting opportunity to contribute a rapidly expanding area of sedimentology and use innovative approaches to investigate the fundamental physical, chemical and biological controls that act upon mudstone variability. Up to 60% of future hydrocarbon production may derive from unconventional Shale Gas sources. This PhD would aid understanding of known plays and examine the potential for the UKCS Shale Gas plays. Until recently geologists have assumed that mudstone successions were largely homogenous with any inhomogeneties produced by changes in primary productivity and anoxia at the time of deposition. Recent studies utilising optical and electron optical methods reveal that these rocks are much more variable than previously assumed. Successive strata (mm and sub-mm scales) can contain very different proportions of material derived from clastic input, primary productivity and diagenetic processes. These studies also reveal that variability is systematic and can be interpreted in terms of varying detrital inputs, biological productivity and subsequent diagenesis using sequence stratigraphic principles. Therefore understanding the fundamental controls that underpin lithofacies variability at mm scales has significant implications for interpreting climate change signals preserved in these strata and for effectively exploring for unconventional shale gas plays. Lithofacies variability at these scales controls the distribution and abundance of organic matter and their hydrofracturing properties. This proposal is linked to, but distinct from, 'Lithofacies variability in mixed clastic carbonate fine-grained successions: implications for identifying Shale Gas exploration sweet spots' submitted by Dr. J. Macquaker (University of Manchester). Major aim: to investigate the variability of siliciclastic mudstone lithofacies in order to determine the fundamental controls on sedimentation and the preservation of organic matter in fine-grained successions. Key Objectives: (1) Describe the variability in mudstone character from Pennsylvanian siliciclastic successions from northern England using a multidisciplinary approach (field logging, optical, electron optical, whole rock geochemical methods). (2) Interpret this variability in terms of fundamental physical, chemical and biological controls operating at and close to the sediment water interface. (3) Investigate geochemical proxies as indicators of redox conditions during deposition that may correspond with enhanced organic matter deposition/preservation. (4) Generate integrated high-resolution sequence stratigraphic models in order to determine the temporal and spatial processes that might lead to unusual silica enrichment in specific environments. Deliverables (1) A mudstone lithofacies scheme, highlighting organic rich facies, that can be interpreted in terms of fundamental controls on mudstone deposition (Objectives 1 and 2). (2) An assessment of geochemical proxies, links to mudstone lithofacies and their significance in interpreting changing redox conditions and association with enhanced organic matter preservation (Objective 3). (3) A high-resolution sequence stratigraphic model that draws together all elements of the basin fill, and examines the temporal and spatial distribution, and preservation, of organic-rich mudstone lithofacies in a siliciclastic-dominated, shallow-marine setting. (Objective 4) The student will be trained in sedimentological and sequence stratigraphic analysis; sedimentological and palaeontological field and laboratory procedures; optical and electron microscopy, geochemical preparation, analytical and interpretation techniques (XRF, XRD and organic carbon). The student will spend between 3 and 18 months working within the company (Leatherhead and Upstream Research Company, Houston), in addition to formal meetings with ExxonMobil supervisors.

这个博士学位是一个令人兴奋的机会，有助于沉积学的迅速扩大的领域，并使用创新的方法来研究作用于泥岩变异性的基本物理，化学和生物控制。未来高达60%的碳氢化合物产量可能来自非常规页岩气来源。这个博士学位将有助于了解已知的游戏和检查的潜力UKCS页岩气游戏。直到最近，地质学家们还认为泥岩序列基本上是同质的，任何不均匀性都是由沉积时初级生产力的变化和缺氧造成的。最近利用光学和电子光学方法的研究表明，这些岩石比以前假设的要多变得多。连续的地层（毫米和亚毫米级）可能包含非常不同比例的物质，这些物质来自碎屑输入、初级生产力和成岩过程。这些研究还表明，变异性是系统的，可以解释为不同的碎屑输入，生物生产力和随后的成岩作用，使用层序地层学原理。因此，了解在毫米尺度上支撑岩相变化的基本控制因素对于解释保存在这些地层中的气候变化信号和有效勘探非常规页岩气具有重要意义。这些尺度上的岩相变化控制着有机质的分布和丰度及其水力压裂特性。该建议与J. Macquaker博士（曼彻斯特大学）提交的“混合碎屑碳酸盐细粒序列中的岩相变化：识别页岩气勘探最佳点的意义”有关，但又有区别。主要目标：研究硅质泥岩岩相的变异性，以确定沉积作用的基本控制因素和细粒序列中有机质的保存。关键目标：（1）使用多学科方法（现场测井、光学、电子光学、全岩地球化学方法）描述英格兰北方宾夕法尼亚期硅质岩系泥岩特征的变异性。(2)解释这种变化的基本物理，化学和生物控制和接近沉积物-水界面。(3)调查地球化学指标，作为沉积过程中氧化还原条件的指标，可能与有机物沉积/保存的增强相对应。(4)生成综合的高分辨率层序地层模型，以确定可能导致特定环境中二氧化硅异常富集的时间和空间过程。（1）泥岩岩相图，突出有机质富集相，可根据泥岩沉积的基本控制因素进行解释（目标1和2）。(2)评估地球化学代用指标、与泥岩岩相的联系及其在解释氧化还原条件变化和有机质保存增强方面的意义（目标3）。(3)一个高分辨率层序地层模型，汇集了盆地填充物的所有元素，并检查了以硅质碎屑为主的浅海环境中富含有机物的泥岩岩相的时空分布和保存情况。（目标4）学生将接受以下方面的培训：沉积学和层序地层学分析;沉积学和古生物学领域和实验室程序;光学和电子显微镜，地球化学制备，分析和解释技术（XRF，XRD和有机碳）。学生将在公司（莱瑟黑德和休斯顿上游研究公司）工作3到18个月，此外还将与埃克森美孚主管进行正式会谈。