辽宁盘一井地下流体异常特征、预测方法及异常成因研究

Characteristics,Prediction Methods and Mechanism of Underground Fluid Anomalies in Panjin No.1 Well,Liaoning Province

辽宁盘一井地下流体自1973年开始观测以来,发展至今不仅流体观测手段逐渐丰富,积累了大量观测资料,并在多次地震前出现明显异常,为地震监测预报提供了重要借鉴,本文对辽宁盘一井地下流体异常特征、预测方法及异常成因进行了研究。对盘一井不同测项的震前异常特征及预测方法分析结果表明,水氡以趋势性和临震异常为主,氢气以短临异常为主,使用阈值法、差分分析法及临界慢化法识别异常效果较好;氯离子以短临异常为主,使用原始曲线分析方法提取异常效果较好。盘一井水氡异常成因分析表明,盘一井各测项浓度异常与测点周边地震活动强弱、区域应力场变化等存在紧密关系。在压应力状态下,该井氡浓度异常往往表现为高值异常;在张性应力状态下,该井氡浓度异常往往呈“V”字形态变化。

The underground fluid of Panjin No.1 well has been observed since 1973,which has not only enriched the means of observation,but also accumulated a large amount of observation data.The Panjin No.1 well has showed obvious abnormal changes before the several earthquakes,that provides an important reference for earthquake monitoring and prediction.In this paper,we studied the characteristics,prediction methods and mecha-nism of underground fluid anomalies in Panjin No.1 well.The analysis results that the anomaly characteristics and prediction methods of the underground fluid in Panjin No.1 well before earthquake indicate that,radon is mainly characterized by trend and impending anomalies,hydrogen is mainly characterized by short-term and imminent anomalies,which can use the threshold analysis,differential analysis and the critical slowing down methods to obtain a good results in identifying anomalies.Chloride ion is mainly characterized by short-term and imminent,which can use the original curve analysis method to have a good effect in extracting anomalies.The research results of the abnormal mechanism of under-ground fluid in Panjin No.1 well indicate that,there is a close relationship among the ab-normal concentration of each measurement item,the strength of seismic activity and chan-ges in regional stress field.Under the condition of regional compressive strain,the radon precursory anomalies in the Panjin No.1 well observation is characterized by increasing concentrations.Under a tensile strain state,the anomalies is characterized by V-shaped changes in radon concentrations.