中国大陆科学钻探工程主孔地下流体特征及与地震活动的关系初步研究

Geochemistry of some fluid compositions in the mud of CCSD main well and their relations to seismicity

收集了中国大陆科学钻探主孔工程(CCSD)主孔中117-2045 m深度地下流体某些组分(He、Ar、CO2、CH4)的浓度资料和2001年7月1日至2002年4月30日时间段内钻孔周围500 km范围内震级ML≥1.0地震目录资料,对其流体资料进行日均值处理、差分分析和最大相关系数处理。由日均值浓度看出地震前后He、Ar、CO2、CH4浓度存在明显异常;最大相关系数分析表明,CH4和CO2组分两者相关性好,最大相关系数平均值为0.95,均方差为0.08,说明两者可能具有相同的来源。CH4和CO2浓度日均值最大相关系数在地震前后出现明显的异常波动。主孔中的地下流体特征及与周围地震活动的对应关系揭示大陆科学钻探主孔中的地下流体异常与区内地震活动可能存在一定关系。

The concentrations of some fluid compositions such as He, Ar, CO2 and CH4 in the mud of CCSD main well at depths between 100 and 2045m are collected and analyzed in this paper. To study the relationship between the anomalous variations of fluids and seismic activities within the focus area, the authors have obtained and compiled seismic catalogues with magnitude over 1. 0 in the period of July 1, 2002-April 30, 2002. The concentrations of these fluid components (He, Ar, CO2 and CH4) are analyzed and processed using the daily statistics, the calculus of difference and the maximum coefficient of correlation of CO2-CH4. It is indicated from these results that the anomalous variation occurs before or after seismic activity. From the features of some fluid composition in the CCSD main well and the seismic activity at CCSD site within the radius if 500 km, it can be concluded that the features of fluids in the main well were possibly responsible for seismic activity.