Fluid Flow and Growth of Active Salt Structures at Decadal Timescales: Paradox Basin, Utah

十年时间尺度的流体流动和活性盐结构的生长：犹他州悖论盆地

• 批准号: 1119173
• 负责人: Karl Mueller
• 金额: $ 30.31万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-10-01 至 2017-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1119173&HistoricalAwards=false
• 关键词: Fluid; Flow; Growth; Active; Salt

This project is aimed at quantifying how fluid flow in evaporite (salt) deposits controls 3D brittle strain in the upper crust, in addition to solute transfer and it's connections between Earth's surface and subsurface. The research will help understand how transient fluid flux drives short-term brittle strain at timescales of days to decades and distances of tens of meters to kilometers. The research team will characterize active surface deformation with 1:5,000 scale field mapping and construction of cross sections, analysis of InSAR scenes, and installation of a three-component extensometer (creep meter) across a rapidly slipping boundary fault. In addition researchers will assess patterns and rates of surface and groundwater flowing through or directly into buried salt and its effect on rock strength as governs by hydraulic weakening and dissolution. Three-dimensional mechanical modeling will be undertaken to test models constrained by observed strain at the surface, fluid flux, groundwater modeling, structural geology and topography. The goal is to fully characterize how fresh water moves through the salt system, how that modulates plastic strain by dissolution and changes on the strength of halite and the role topography plays in coupled surface and subsurface processes. The work?s broader significance includes understanding how fluid flow and strain in salt systems evolves at scales not available by other means. The researchers are particularly interested in determining how transient surges in plastic salt flow might respond to input of the seasonal influx of surface runoff and groundwater recharge. The field work is located in the Paradox evaporite basin in eastern Utah, a region noted for its extraordinarily well-exposed rocks and wealth of available surface and subsurface data.This work will build on the recent discovery of transient surges in unconfined salt bodies in western Iran and the Dead Sea in Israel. These structures, which consist of emergent domes and flows of pure rock salt are modern examples of geologic structures analogous to glaciers and are similar to features in areas such as the Gulf of Mexico that contain great petroleum reserves. The research will define the conditions that control deformation and growth of salt structures and relate this to conditions such as the inflow of fresh water and outflow of saline brines within them. These studies will utilize a wide array of techniques and data previously unavailable in past studies. The ultimate goal is thus to define the physical conditions that control and guide their development in order that this may be applied in general to other salt structures around the world. On a global scale, this work is of interest to responsible resource exploration in salt basins for hydrocarbons. For instance the Deepwater Horizon well that created the oil spill in the Gulf of Mexico in 2010 was being drilled into a salt structure, and the cause of the blowout was an unforeseen increase in fluid pressure. In addition, this work holds the promise to quantify the saline brine influx into the Colorado River and shallow groundwater and its effect on the degradation of water quality in the largest source of fresh water in the southwestern United States.

该项目旨在量化蒸发岩(盐)沉积中的流体流动如何控制上地壳的3D脆性应变，以及溶质迁移及其在地球表面和地下之间的联系。这项研究将有助于理解瞬时流体流量如何在几天到几十天的时间尺度上驱动短期脆性应变，并在几十米到千米的距离内驱动。研究小组将通过1：5,000比例尺的现场测绘和横截面构造，InSAR场景分析，以及在快速滑动的边界断层上安装三分量延伸仪(蠕变仪)来表征活跃的地表变形。此外，研究人员将评估地表和地下水流经或直接流入埋藏盐层的模式和速率，以及它对水力削弱和溶解所控制的岩石强度的影响。将进行三维机械模拟，以测试受地表观测应变、流体流量、地下水模拟、构造地质和地形约束的模型。其目标是充分描述淡水如何在盐岩系统中流动，如何通过溶解和盐岩强度的变化来调节塑性应变，以及地形在地表和地下耦合过程中所起的作用。S的工作具有更广泛的意义，包括了解盐系统中流体流动和应变是如何在其他方法无法获得的范围内演化的。研究人员特别感兴趣的是，确定塑料盐流中的瞬时涌流可能会对季节性地表径流和地下水补给的输入做出怎样的反应。这项野外工作位于犹他州东部的Paradox蒸发岩盆地，该地区以其异常暴露的岩石和丰富的地面和地下数据而闻名。这项工作将建立在最近在伊朗西部和以色列死海的无约束盐体中发现的瞬变涌浪的基础上。这些由浮现的穹顶和纯岩盐流组成的结构是类似于冰川的地质结构的现代例子，类似于墨西哥湾等蕴藏着大量石油储量的地区的特征。这项研究将确定控制盐岩结构变形和生长的条件，并将其与淡水流入和盐湖卤水流出等条件联系起来。这些研究将利用过去研究中没有的一系列技术和数据。因此，最终目标是确定控制和指导其发展的物理条件，以便将其普遍应用于世界各地的其他盐结构。在全球范围内，这项工作对在盐湖盆地进行负责任的碳氢化合物资源勘探具有重要意义。例如，2010年在墨西哥湾造成石油泄漏的深水地平线油井正在钻井进入盐岩结构，而井喷的原因是流体压力意外增加。此外，这项工作有望量化流入科罗拉多河和浅层地下水的盐水及其对美国西南部最大淡水来源地水质退化的影响。