摘要:
传统地热化探技术(以土壤微量元素为主)在隆起山地型地热田勘查中的应用较多,用以圈定地热异常区和勘查隐伏断裂构造,但在沉积盆地型地热田勘查中应用较少,主要原因在于沉积盆地型地热田热水埋藏较深,保存条件较好,抑制了地热水中无机元素等伴生物向地表扩散的强度,影响了化探技术对沉积盆地型地热田的预测效果.考虑到沉积盆地型地热田热水富含的伴生气体(甲烷、二氧化碳等),因其穿透力较强,易于在地表聚集而得以检测,因此采用壤中气方法在沉积盆地型地热田——冀中坳陷河北雄县地热田开展试验,进行近地表地球化学特征与地热响应关系解剖.结果表明,壤中气甲烷、氢气是圈定雄县地热田地热最有利富集区的有效指标,该结果为相似的沉积盆地型地热田勘探提供了地球化学依据.
Abstract:
The traditional geochemical exploration technique,which uses mainly trace element methods for geothermal systems and can delineate geothermal anomaly areas and search for concealed fault structures,is applied much more to the prospecting in geothermal systems of uplifting mountain type than that in geothermal systems of sedimentary basin type.The conditions of geothermal systems of sedimentary basin type,such as depth of hot water and good preservation which restricts the diffusion of the inorganic elements in geothermal water towards surface,lead to poor prediction effectiveness of geochemical exploration technique.In view of the fact that hot water in geothermal systems of sedimentary basin type is rich in the associated gas such as methane and carbon dioxide,and hence these gases are easy to micro-seep to surface and can be detected because of their strong penetrating power,the authors applied the soil gas method to the field trial to study the responding relationship between surface geochemical characteristics and the geothermal water enrichment area in the geothermal system of sedimentary basin type in Xiongxian County,Hebei Province.The results show that methane and hydrogen in soil gas are effective indicators to delineate the most favorable enrichment area in the geothermal systems of Xiongxian County,thus providing geochemical basis for geothermal systems exploration of similar types.
下载: