Evaluation of shear slip stress transfer mechanism for induced microseismicity at In Salah CO2 storage site
Evaluation of shear slip stress transfer mechanism for induced microseismicity at In Salah CO2 storage site
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DOI：
10.1016/j.ijggc.2021.103302
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发表时间：
2021-05
影响因子：
3.9
通讯作者：
Wenzhuo Cao;Ji‐Quan Shi;S. Durucan;A. Korre
中科院分区：
文献类型：
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作者：
Wenzhuo Cao;Ji‐Quan Shi;S. Durucan;A. Korre
断层活化引起的应力传递在诱发地震活动中起重要作用。这项工作的目的是调查在何种程度上的剪切滑移应力传递机制可能有助于4个月期间的水平注入威尔斯（KB-502）在因萨拉赫CO2存储网站周围的微震活动的提高。建立在以前的油藏建模和历史匹配工作的作者，耦合地质力学和油藏建模的CO2注入在KB-502进行，具有显式模拟注入引起的断层活化和应力转移，并实施应变依赖渗透率模型，以代表断层水文行为。与之前的结果相比，这种方法可以大大改善与KB-502油田井底压力的整体匹配，其中未考虑断层带再活化和相关的动态渗透率行为，特别是在4个月的关注期内。根据耦合模拟结果，库仑应力变化被用来评估在KB-502与CO2注入引起的断层再活化相关的增强微震活动的潜力。对微震活动可能性的分析表明，地震事件可能发生在水力连接区和应力转移影响区。计算的库仑应力变化在近断层地区的变化相比，有利的提高现场记录的地震活动期间建模。综合解释的微震监测和耦合地质力学和水库建模表明，剪切滑移应力转移机制是积极的，并促成了诱发地震活动在In Salah的发生。
Stress transfer caused by injection-induced fault reactivation plays a significant role in triggering induced seismicity. This work aims to investigate to which extent the shear slip stress transfer mechanism might have contributed to a 4-month period of heightened microseismicity around one of the horizontal injection wells (KB-502) at the In Salah CO2storage site. Building upon previous reservoir modelling and history matching work by the authors, coupled geomechanical and reservoir modelling of CO2injection at KB-502 was carried out, featuring the explicit simulation of injection-induced fault reactivation and stress transfer, and the implementation of a strain-dependent permeability model to represent the fault hydrological behaviour. This approach allows a much-improved overall match to the field bottomhole pressures at KB-502 over the previous results, where fault zone reactivation and associated dynamic permeability behaviour were not considered, especially over the 4-month period of interest. Based upon the coupled modelling results, Coulomb stress changes were used to evaluate the potential for enhanced microseismicity related to CO2injection-induced fault reactivation at KB-502. Analyses on the potential for microseismicity have shown that seismic events are likely to take place in both hydraulically connected regions and stress transfer influenced regions. The variation of computed Coulomb stress changes in near-fault areas compares favourably with the heightened field recorded seismicity during the period modelled. The integrated interpretation of microseismic monitoring and coupled geomechanics and reservoir modelling have suggested that the shear slip stress transfer mechanism was active and contributed to the occurrence of induced seismicity at In Salah.