Pioneering the use of nanoseismics as a site investigation tool

开创性地使用纳米地震作为现场调查工具

• 批准号: EP/K005812/1
• 负责人: Stella Pytharouli
• 金额: $ 12.7万
• 依托单位: University of Strathclyde
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FK005812%2F1
• 关键词: Pioneering; use; nanoseismics; site; investigation

Field evidence shows that faults and fractures can act as focused pathways or barriers for fluid migration. As a result, detailed imaging, i.e. location, orientation and hydraulic properties, of fracture networks not visible at the surface, is crucial for modern engineering applications, such as CO2 storage, geothermal energy exploitation, tunnelling. To-date, such information is not available at the required level of detail and accuracy. Currently, methods for the imaging of fractures at a resolution of less than 100m are based on seismic reflection/refraction and surface waves. These methods require a large number of sensors (usually over 100 making their application costly) and their success highly depends on the elastic properties of the rock and the inclination (dip) of the underlying strata. The fractures can be identified at a maximum depth of 100 m below ground surface. The main aim of this project is to (1) develop a new site investigation tool that utilises micro-seismicity for the identification of individual fractures that accommodate flow at depths down to 4km and (2) build the skills and knowledge necessary to implement it within industrial applications directly related to fluid flow systems at depth. This will result in the publication of a new protocol for microseismic borehole stimulation to image fractures that accommodate flow over large spatial scales. A new monitoring technology will be used and further extended: short-period seismometers with the combination of "Hypoline" software. The latter can help distinguish between weak signals and noise and reduces the signal-to-noise ratio to 1:1. The combination of sensors and software is known as nanoseismics (NS). Although new and very promising, this technique has a limitation: it can provide a location, time of origin and magnitude for the recorded events, however, its does not provide an estimation of the location error, nor the moment tensor that would allow determination of fracture orientation, two very important parameters for providing a detailed image for engineering applications. This project will pursue to further extend this capability for the determination of individual fracture orientations and quantification of fracture permeability.There is a unique opportunity to found both the testing of the efficiency of NS as a site investigation tool, and the development of the analysis technique, by recording data at an existing site with high potential to act as geothermal resource in NE England. Permission has been granted to conduct a series of injection tests at a borehole on the site in order to record the induced microseismicity and locate and image the fractures that accommodate the flow at a depth of up to 2km. The outcomes of this research will contribute to a better understanding of sub-surface processes through characterisation of heterogeneous flowing fracture networks over large spatial scales.

现场证据表明，断层和裂缝可以作为流体运移的集中通道或屏障。因此，详细的成像，即在地表不可见的裂缝网络的位置，方向和水力特性，对于现代工程应用至关重要，例如CO2储存，地热能开采，隧道施工。迄今为止，这类资料的详细程度和准确性都达不到要求。目前，分辨率小于100米的裂缝成像方法是基于地震反射/折射和表面波。这些方法需要大量的传感器（通常超过100个，使得它们的应用成本高），并且它们的成功高度取决于岩石的弹性特性和下伏地层的倾斜度（倾角）。裂缝可在地表以下100 m的最大深度处识别。该项目的主要目的是（1）开发一种新的现场调查工具，利用微震活动来识别可容纳4 km深处流量的单个裂缝，以及（2）建立必要的技能和知识，以便在与深度流体流动系统直接相关的工业应用中实施该工具。这将导致出版一个新的协议，为微震井眼刺激图像裂缝，适应大空间尺度上的流动。将使用并进一步推广一种新的监测技术：结合“Hypoline”软件的短周期地震仪。后者可以帮助区分弱信号和噪声，并将信噪比降低到1：1。传感器和软件的结合被称为纳米地震仪（NS）。虽然新的和非常有前途的，这种技术有一个局限性：它可以提供一个位置，时间的起源和记录的事件的大小，但是，它不提供一个估计的位置误差，也没有矩张量，将允许确定裂缝的方向，两个非常重要的参数，为工程应用提供详细的图像。该项目将寻求进一步扩展这种能力，用于确定单个裂缝方向和裂缝渗透率的量化。有一个独特的机会，可以通过记录英格兰东北部现有地热资源潜力很大的地点的数据，来测试NS作为现场调查工具的效率，并开发分析技术。已获准在现场钻孔进行一系列注入测试，以记录诱发的微震活动，并定位和成像容纳深度达2公里的水流的裂缝。这项研究的成果将有助于更好地了解地下过程，通过表征非均质流动裂缝网络在大的空间尺度。

项目成果

Landslides on soft soils: failure modes and precursors

软土上的山体滑坡：破坏模式和前兆

• 发表时间: 2015
• 作者: Yfantis G.

Spectral Characteristics of Landslide Induced Seismicity: Experimental Validation Based on the Use of an Up-Scaled Sheer Box.

滑坡诱发地震活动的光谱特征：基于使用放大的纯粹箱的实验验证。

• 发表时间: 2014
• 作者: Yfantis G.

Determination of the seismic signatures of landslides in soft soils: A methodology based on a field scale shear box

软土中滑坡地震特征的确定：基于现场规模剪切盒的方法

• DOI: 10.1016/j.enggeo.2020.105853
• 发表时间: 2020
• 期刊: Engineering Geology
• 影响因子: 7.4
• 作者: Yfantis G