地下流体注入诱发地震机理及其对CO_2地下封存工程的启示  

Mechanism of Underground Fluid Injection Induced Seismicity and Its Implications for CCS Projects

作　　者：魏晓琛[1] 李琦[1] 邢会林 李霞颖 宋然然[1] 

机构地区：[1]中国科学院武汉岩土力学研究所、岩土力学与工程国家重点实验室,湖北武汉430071 [2]Centre for Geosciences Computing,School of Earth Sciences,The University of Queensland,St.Lucia,QLD 4072,Australia

出　　处：《地球科学进展》2014年第11期1226-1241,共16页Advances in Earth Science

基　　金：国家自然科学基金面上项目“酸气-咸水作用下岩石特异性破坏机理研究”(编号:41274111);国土资源部公益性行业科研专项项目“井筒安全注入压力的确定及盖层力学稳定性评价方法研究”(编号:201211063-4-1)资助

摘　　要：二氧化碳地质封存(CO2Capture and Storage,CCS)项目应当评估诱发地震的潜在可能性。中强震、强震危及人类生命财产安全,有感地震甚至微震也对CO2储区的盖层完整性构成威胁,增加泄漏风险。地热开发、页岩气开发及油气增产等的水压致裂过程中都伴随有地下流体的注入,且时有地震诱发的案例。诱发地震活动通常在流体注入压力较高时沿已有断层发生,因此可通过应力分析等对其发生机理进行研究。超临界状态CO2密度比水小,在地层深部可能会形成密度流或者与构造中先存的水岩发生相互作用,进而导致渗透率和压力变化并引发地震活动。综述了全球相关的研究进展,主要从地震成因机理入手,考虑超临界CO2性质的特殊性,结合商业尺度和实验尺度的流体注入项目和地震监测分析,研究其对储区盖层完整性的影响。以期通过适当的选址、注入方法及监测方案的优化来避免破坏性地震的发生。CO2 capture and storage projects must consider the potential possibility ofinjection induced seismici- ty. Moderate earthquakes and strong earthquakes may endanger human life and property, and even felt earthquakes and microquakes also pose a threat to seal integrity of CO2 reservoir and increase the risk of leakage. Underground- fluid injection induced seismicityusually happens in some geoengineering projects such as waste fluid disposal, EOR and EGS, and it occurs when fluid is injected along the fault. Therefore, it can be studied through stress analysis. The density of supercritical CO2 is smaller than water, which may develop density flow in the deep strata or water- rock interactions in pre-existing structures, and cause the variation in permeability and pressure to induce a seismic activity. In this paper, we reviewed the mechanism of undergroundfluid injection induced seismicity with the focus of CCS, combined with fluid injection projects and seismic monitoringanalysis in both commercialscale and experi- mental scale, to investigate its impact on the integrity of the cap rock of the reservoir. Finally, we summarized the appropriate site selection, injection methods and monitoring programs to prevent the occurrence of inducedseismici- tv.

关 键 词：地下注水 CCS 超临界CO2 诱发地震 盖层完整性 

分 类 号：P315[天文地球—地震学]