本文开展汶川地震断裂带科学钻探现场流体研究，探讨了泥浆添加剂产生的化学反应以及钻孔中岩性变化引起的流体异常特征，并在排除这些影响因素的情况下，讨论地震期间流体的异常。研究表明在WFSD-4S钻进期间发生的两次较大地震前均伴有Rn、Ar、N2和O2等气体异常现象，其中氡的日均值均超出背景值的2.5倍。根据岩心观察得到WFSD-4S钻井地区主断层约在1084 m，而在断层之上931 m处开始出现了大量气体的高值异常，该异常可能是由于地震孕育过程中地下气体的运移通道被打开造成气体向上迁移，使断层气体的响应特征提前发生。%This paper deals with the in-site real-time fluid analysis in the drill hole WFSD-4S. The abnormal fluid during the earthquake was discussed after excluding the influence of chemical reaction affected by mud additives and anomaly characteristics caused by lithologic changes. The research shows that two strong earthquakes were accompanied by abnormal occurrence of Rn, Ar, N2 and O2 in WFSD-4S. What deserves attention is the daily average concentrations of radon were over 2.5 times higher than the background value. The mud gas yielded high concentrations above Principal Slip Zone (PSZ) in 931 m,which should appear in 1084m through the lithology investigation. It is inferred that the underground gas migration channel was opened and gas migrated upward because of the earthquake preparation process, which resulted in anticipating the response characteristics of fault gases.
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