Time lapse seismic is a vital component of the monitoring and verification of virtually any geosequestration project. Stage 2C of the CO2CRC Otway project is designed to test the limits of land 3D time-lapse (4D) seismic in the monitoring of small-scale CO2 injection. The 4D seismic monitoring program of Stage 2C of the Otway Project includes a baseline survey (BL); three monitor surveys (M1–M3) obtained during the injection of CO2-rich gas into the saline aquifer at a depth of 1.5 km at the injection intervals of 5, 10, and 15 kt; and two post-injection surveys (M4 and M5), acquired one and two years after the end of injection. Reliable time-lapse changes among the 4D surveys were obtained using a buried receiver array. Analysis of the seismic cubes and attributes demonstrates that during and after injection the plume spreads laterally only in southeastern direction. The results demonstrate strong time-lapse signal corresponding to the injection level and the absence of any observed leakage into the overburden. The plume evolution is reliably observed and traced from M1 to M5 surveys with most of the changes occurring between the BL and M4 surveys.

中文翻译：

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4D 地面地震监测注入过程中和注入后小 CO2 羽流的演变：CO2CRC Otway 项目研究

延时地震是几乎所有地质封存项目监测和验证的重要组成部分。CO2CRC Otway 项目的第 2C 阶段旨在测试陆地 3D 延时 (4D) 地震在监测小规模 CO2 注入方面的限制。Otway 项目 2C 阶段的 4D 地震监测计划包括基线调查（BL）；在以 5、10 和 15 kt 的注入间隔将富含 CO2 的气体注入 1.5 公里深度的咸水含水层期间获得的三项监测调查（M1-M3）；和两次注射后调查（M4 和 M5），在注射结束后一年和两年获得。使用掩埋接收器阵列获得了 4D 调查之间可靠的延时变化。对地震立方体和属性的分析表明，在注入期间和之后，羽流仅在东南方向横向扩散。结果表明，与注入水平相对应的强延时信号和没有观察到的任何泄漏到覆盖层中。从 M1 到 M5 调查可靠地观察和追踪羽流演化，其中大部分变化发生在 BL 和 M4 调查之间。