Dynamics of geologic CO2 storage and plume motion revealed by seismic coda waves
Dynamics of geologic CO2 storage and plume motion revealed by seismic coda waves
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DOI：
10.1073/pnas.1810903116
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发表时间：
2019-02-12
影响因子：
11.1
通讯作者：
Marone, Chris
中科院分区：
文献类型：
--
作者：
Zhu, Tieyuan;Ajo-Franklin, Jonathan;Marone, Chris
量化封存的CO2羽流的动态对于安全的长期储存至关重要，可以为羽流范围提供指导，并检测地层密封失效。然而，现有的地震监测方法的基础上波的反射或透射探测有限的岩石体积和它们的灵敏度降低，CO2饱和度的增加，减少了它们的实用性定量羽流质量估计。在这里，我们表明，地震散射尾波，连续钻孔监测过程中获得的，能够照亮的细节，在74小时的CO2注入实验在Frio-II井代顿，得克萨斯州的CO2羽流。我们的研究揭示了一个连续的速度降低，在动态注入CO2，结果，增强和显着改善了先前的分析的基础上P波到达时间。我们发现，速度降低与注入的累积CO2质量是非线性相关的，并将这种相关性归因于尾波反复采样储层中累积CO2的非均匀分布。最后，由于我们的方法不依赖于P波到达时间或需要良好的约束波反射，它可以与许多源-接收器的几何形状，包括那些外部的水库，这降低了风险引入油藏监测威尔斯井。我们的研究结果提供了一种定量CO2监测和羽流演变的方法，提高了CO2注入和储存的安全性和长期规划。
Quantifying the dynamics of sequestered CO2 plumes is critical for safe long-term storage, providing guidance on plume extent, and detecting stratigraphic seal failure. However, existing seismic monitoring methods based on wave reflection or transmission probe a limited rock volume and their sensitivity decreases as CO2 saturation increases, decreasing their utility in quantitative plume mass estimation. Here we show that seismic scattering coda waves, acquired during continuous borehole monitoring, are able to illuminate details of the CO2 plume during a 74-h CO2 injection experiment at the Frio-II well Dayton, TX. Our study reveals a continuous velocity reduction during the dynamic injection of CO2, a result that augments and dramatically improves upon prior analyses based on P-wave arrival times. We show that velocity reduction is nonlinearly correlated with the injected cumulative CO2 mass and attribute this correlation to the fact that coda waves repeatedly sample the heterogeneous distribution of cumulative CO2 in the reservoir zone. Lastly, because our approach does not depend on P-wave arrival times or require well-constrained wave reflections it can be used with many source-receiver geometries including those external to the reservoir, which reduces the risk introduced by inreservoir monitoring wells. Our results provide an approach for quantitative CO2 monitoring and plume evolution that increases safety and long-term planning for CO2 injection and storage.