祁连山天然气水合物地球化学勘查方法稳定性和异常重现性分析

根据祁连山木里地区已知天然气水合物上方不同期次近地表土壤地球化学勘查重复性试验,对土壤酸解烃、顶空气、荧光光谱、碳酸盐等指标方法的稳定性及异常重现性问题进行研究和探讨。结果表明,各项化探指标不同期次含量最大值等特征值虽然存在一定程度的差异,但是其数据波动特征和数据结构是相对一致的。顶空气甲烷、酸解烃、荧光光谱和碳酸盐方法指标前后两次测量结果均具有较高的相关性,配对T-检验显示顶空气轻烃、酸解烃和碳酸盐指标数据变化差异不显著,从统计学上看其指标数据具有较好的稳定性。顶空气甲烷、酸解烃、荧光光谱等指标地球化学异常在研究区已知天然气水合物矿区上方具有相似的空间分布特征,说明其化探指标异常空间上具有良好的稳定性和重现性;但是顶空气重烃异常模式、碳酸盐异常强度的变化,反映其具有重现性,但异常稳定性相对较差。这为地球化学勘查在陆域冻土区天然气水合物勘查中发挥作用提供了较好的基础。

The Analysis of Stability and Abnormal Reproducibility of Geochemical Exploration of Natural Gas Hydrate in Qilian Mountain

Based on the repeated experimental results of geochemical exploration over the known natural gas hydrate of Muli area in Qilian Mountain, the stability and anomaly reoccurrence of soil acid hydrocarbon, top-air, fluorescence spectrum, carbonate and other indexes were studied and discussed. The results prove that although there are some differences in the characteristic values, such as the maximum value of the contents of different geochemical exploration indexes, the data fluctuation characteristics and data structure are relatively consistent. The results of the previous two measurements of top air methane, acid hydrocarbon, fluorescence spectrum and carbonates are related, and the paired T-test shows no obvious difference in data variation of above indexes, while the index data have good stability statistically. Geochemical anomalies of top-air methane, acid hydrocarbon, fluorescence spectrum and other indicators have similar spatial distribution characteristics over known natural gas hydrate mining areas in the study area, which indicates that the geochemical anomalies has good stability and reproducibility, while the abnormal pattern of heavy hydrocarbon of top-air and the variation of abnormal intensity of carbonates reflects that the anomalies has better reoccurrence with worse stability.