Impact of Geochemical Weathering on Fault Zone Architecture

地球化学风化对断裂带结构的影响

• 批准号: 2283940
• 金额: --
• 依托单位: University of Strathclyde
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2283940
• 关键词: Impact; Geochemical; Weathering; Fault; Zone

Cross-fault flow properties of fault zones have long been studied to constrain their ability to hold a hydrocarbon column. However flow within fault zones can lead them to act as sub-vertical conduits. Faults can act as seal bypass systems, permitting linkage of compartments in conventional hydrocarbon systems. Faults can also provide conduits for gas flow out of unconventional reservoirs, reducing the economic gas in place; or provide pathways for water into unconventional wells, increasing water production and the consequent environmental impacts. There is therefore an urgent need to develop new workflows and tools for quantifying the risk of within-fault flow for a given subsurface fault.The risk of flow within fault zones is affected by the internal structural architecture of the fault, the petrophysical properties of the fault rocks and the interplay of mechanical and chemical processes within the fault zone (fault zone diagenesis). The latter is the least-studied aspect of within-fault flow. The Little Grand Wash and Iron Wash faults, Utah, provide surface analogues for faults in unconventional and conventional reservoirs respectively. The sites represent excellent natural labs for characterising the processes that constrain within-fault flow: the research team have collected unparalleled data at both sites from surface exposures and wells (both scientific and industry) and have extensive datasets of fault zone structure subsurface samples of fault rocks. Subsurface samples allow exploration of the appropriate ways to correct for the effect of weathering on surface analogues. The PhD student will collect new field data to investigate the effect of geochemical reactions on both the mechanical response of the fault rocks and the hydraulic properties of the fault rocks. They will constrain the fault zone diagenesis using petrological,SEM techniques and whole-rock chemical and isotopic analyses; use state of the art flow modelling developed at Strathclyde to investigate the range of likely within-fault flow scenarios; collect new mechanical data in Strathclyde geo-mechanics labs; and develop a predictive workflow/tool for within-fault flow. Finally they will validate this tool against industry datasets both in the literature and provided by NERC CDT partners.

长期以来，人们一直在研究断层带的跨断层流动特性，以限制其容纳碳氢化合物柱的能力。然而，断层带内的流动可能导致它们充当次垂直管道。故障可以充当密封旁路系统，允许传统碳氢化合物系统中的隔室连接。断层还可以为非常规储层的天然气流出提供通道，从而减少地质储量中的经济天然气；或者为水进入非常规井提供通道，增加水产量并减少随之而来的环境影响。因此，迫切需要开发新的工作流程和工具来量化给定地下断层的断层内流动风险。断层带内的流动风险受到断层内部结构结构、断层岩石的岩石物理性质以及断层带内机械和化学过程相互作用（断层带成岩作用）的影响。后者是断层内流动研究最少的方面。犹他州的 Little Grand Wash 断层和 Iron Wash 断层分别为非常规和常规储层中的断层提供了表面类似物。这些地点是表征限制断层内流动过程的优秀自然实验室：研究团队在这两个地点从地表暴露和井（科学和工业）收集了无与伦比的数据，并拥有断层岩石断层带结构地下样本的广泛数据集。地下样本可以探索纠正风化对地表类似物影响的适当方法。博士生将收集新的现场数据，以研究地球化学反应对断层岩石的机械响应和断层岩石的水力特性的影响。他们将利用岩石学、扫描电镜技术以及全岩化学和同位素分析来约束断裂带成岩作用；使用斯特拉斯克莱德开发的最先进的流动模型来研究可能的故障内流动场景的范围；在斯特拉斯克莱德地质力学实验室收集新的力学数据；并开发用于故障内流的预测工作流程/工具。最后，他们将根据文献中和 NERC CDT 合作伙伴提供的行业数据集验证该工具。