The microseismic response at the In Salah Carbon Capture and Storage (CCS) site
The microseismic response at the In Salah Carbon Capture and Storage (CCS) site
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DOI：
10.1016/j.ijggc.2014.11.014
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发表时间：
2015
影响因子：
3.9
通讯作者：
A. Stork;J. Verdon;J. Kendall
中科院分区：
文献类型：
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作者：
A. Stork;J. Verdon;J. Kendall
2004年，在InSalah碳捕获和储存（CCS）现场开始注入二氧化碳（CO 2）进行深层储存，并于2009年安装了一个试点微震监测阵列。In Salah项目提供了一个不寻常的数据集，因为它是第一个监测微震活动的主要非提高石油采收率（EOR）CCS项目。本文概述了一个广泛的地震学研究，使用一系列的技术，主要依靠一个单一的三分量检波器的数据。重要的信息是来自数据，如事件的位置，事件的大小和断裂特征，可以在实时使用，以调节地质力学的网站，以二氧化碳注入的反应。事件发生率与CO2注入率密切相关，共检测到9506个地震事件。一个精心选择的事件子集的位置估计发生在或低于注入间隔，从而排除故障或裂缝激活引起的CO2迁移在浅部。在注入层段上方可能发生了极少数井约束位置较少的事件（11）。然而，没有微震证据表明这些事件与CO2注入有关，我们认为它们是由应力转移而不是CO2迁移到盖层中引起的。所观察到的最大力矩大小，M w= 1.7，是一致的，在注入深度与估计的裂缝尺寸。利用剪切波分裂分析估计的裂缝方位近似为NW-SE，与从测井数据推断的裂缝方位一致。在高注入速率期间，各向异性程度略微增加，然后当注入速率下降时，各向异性程度福尔斯下降回到原始值。这意味着二氧化碳正在打开预先存在的裂缝，然后随着压力的降低而关闭。这是一项重要的概念验证研究，证明了CCS项目微震监测的价值，即使是有限的阵列。因此，我们建议，微震监测阵列安装之前，二氧化碳注入在未来的CCS网站，以提高我们的理解，使基线和比较研究成为可能。这还将提供对地质力学对注入的反应的实时监测，使操作人员能够修改注入参数，并帮助确保项目的安全运行。
In 2004, injection of carbon dioxide (CO 2) to be stored at depth began at the In Salah Carbon Capture and Storage (CCS) site and a pilot microseismic monitoring array was installed in 2009. The In Salah project presents an unusual dataset since it is the first major non-Enhanced Oil Recovery (EOR) CCS project to be monitored for microseismicity. This paper outlines an extensive seismological study using a range of techniques, relying mainly on data from a single three-component geophone. Important information is derived from the data, such as event locations, event magnitudes and fracture characteristics, that could be used in real-time to regulate the geomechanical response of a site to CO 2 injection. The event rate closely follows the CO 2 injection rate, with a total of 9506 seismic events detected. The locations for a carefully selected subset of events are estimated to occur at or below the injection interval, thereby ruling out fault or fracture activation caused by CO 2 migration at shallow depths. A very small number of events (11) with less well-constrained locations may have occurred above the injection interval. However, there is no microseismic evidence that these events are correlated with CO 2 injection and we suggest they are caused by stress transfer rather than CO 2 migration into the caprock. The observed maximum moment magnitude, M w= 1.7, is consistent with estimated fracture dimensions at the injection depth. Fracture orientation estimated using shear-wave splitting analysis is approximately NW-SE, in agreement with fracture orientations inferred from logging data. During periods of high injection rates the degree of anisotropy increases slightly and then falls back to original values when injection rates fall. This implies the CO 2 is opening pre-existing fractures which then close as pressure decreases. This an important proof-of-concept study that proves the value of microseismic monitoring of CCS projects, even with a limited array. We thus recommend that microseismic monitoring arrays are installed prior to CO 2 injection at future CCS sites to enhance our understanding by making baseline and comparative studies possible. This would also provide real-time monitoring of the geomechanical response to injection, allowing operators to modify injection parameters and to help ensure the safe operation of a project.