Multiscale characterisation of chimneys/pipes: Fluid escape structures within sedimentary basins
Multiscale characterisation of chimneys/pipes: Fluid escape structures within sedimentary basins
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DOI：
10.1016/j.ijggc.2020.103245
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发表时间：
2021-03
影响因子：
3.9
通讯作者：
A. Robinson;B. Callow;C. Böttner;N. Yilo;G. Provenzano;I. Falcon‐Suarez;H. Marín‐Moreno;A. Lichtsch
中科院分区：
文献类型：
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作者：
A. Robinson;B. Callow;C. Böttner;N. Yilo;G. Provenzano;I. Falcon‐Suarez;H. Marín‐Moreno;A. Lichtsch
通过对地震反射资料的评价，确定了全球沉积盆地内存在流体逸出构造、横切覆盖层地层。地震成像的烟囱/管道被认为是流体流动的可能途径，它可以通过水力将更深的地层与海底连接起来。流体通过覆盖层运移路径的性质必须受到限制，以实现安全、长期的地下二氧化碳（CO2）储存。为了确定聚焦流体管道的物理特性，以及它们是如何控制流体流动的，我们对北海的一个天然活性流体泄漏点进行了调查，即Scanner麻点复合体。在这里，我们表明，一个多尺度，多学科的实验方法需要流体逸出结构的完整表征。地球物理技术对于解决裂缝几何形状和地下结构（如多频地震）以及沉积物的物理参数（如受控源电磁）在很宽的长度尺度（m到km）是必要的。在较小的（毫米至厘米）尺度上，沉积物岩心直接取样，并使用基于实验室的方法评估其物理和化学性质。数值模拟方法弥补了分辨率差距，尽管它们的有效性取决于校准和来自现场和实验室实验数据的约束。此外，能够分辨时间变化的时移地震和声学方法是确定流体通量的关键。通过安装永久性海底基础设施和用自动化工作流程取代人工数据处理，可以促进实验资源利用的未来优化。该研究可用于为测量、监测和验证工作流程提供信息，这将有助于二氧化碳地下储存操作的政策制定、监管和最佳实践。
Evaluation of seismic reflection data has identified the presence of fluid escape structures cross-cutting overburden stratigraphy within sedimentary basins globally. Seismically-imaged chimneys/pipes are considered to be possible pathways for fluid flow, which may hydraulically connect deeper strata to the seabed. The properties of fluid migration pathways through the overburden must be constrained to enable secure, long-term subsurface carbon dioxide (CO2) storage. We have investigated a site of natural active fluid escape in the North Sea, the Scanner pockmark complex, to determine the physical characteristics of focused fluid conduits, and how they control fluid flow. Here we show that a multi-scale, multi-disciplinary experimental approach is required for complete characterisation of fluid escape structures. Geophysical techniques are necessary to resolve fracture geometry and subsurface structure (e.g., multi-frequency seismics) and physical parameters of sediments (e.g., controlled source electromagnetics) across a wide range of length scales (m to km). At smaller (mm to cm) scales, sediment cores were sampled directly and their physical and chemical properties assessed using laboratory-based methods. Numerical modelling approaches bridge the resolution gap, though their validity is dependent on calibration and constraint from field and laboratory experimental data. Further, time-lapse seismic and acoustic methods capable of resolving temporal changes are key for determining fluid flux. Future optimisation of experiment resource use may be facilitated by the installation of permanent seabed infrastructure, and replacement of manual data processing with automated workflows. This study can be used to inform measurement, monitoring and verification workflows that will assist policymaking, regulation, and best practice for CO2subsurface storage operations.