土壤化探在谷露地热田高温地热资源勘查中的应用研究

Experimental Study on Soil Geochemical Method in the Exploration of High Temperature Geothermal Resources in Gulu Geothermal Field

在谷露地热田开展了土壤地球化学As、B和Hg指示元素测量研究。根据指示元素地球化学参数及异常特征分析,表明谷露地热田上方土壤介质中出现的强异常是受到深大断裂导通、浅部断裂构造控制及热水蚀变的综合作用后,叠加形成的累加异常,具有较高异常衬值和重复性好的特征。在热显示区及周边范围开展了面积测量工作,结合元素组合异常特征,综合预测并圈定了谷露地热田的热异常范围。在强异常区段开展钻探查证后,深部揭露最高水温达185℃的多段高温热流体。验证了土壤地球化学指示元素对于覆盖层下的热储具有指示作用,是一种地热资源的有效勘查预测方法。

The measurement of soil geochemical indicator elements including arsenic,boron and mercury was carried out in Gulu geothermal field.According to the geochemical parameters and anomaly characteristics of indicator elements,the strong anomaly in the soil medium above the valley open geothermal field was the cumulative products superimposed by action of deep fault conduction,shallow fault control and hot water alteration,which has the characteristics of high anomaly contrast value and good repeatability.The measurement was conducted in the thermal display area and its surroundings.Combined with the abnormal characteristics of element combination,the thermal anomaly range of Gulu geothermal field was comprehensively predicted and delineated.After drilling verification in the strong anomaly section,multiple sections of high-temperature thermal fluid with the highest water temperature of 185℃were exposed in the deep.The soil geochemical indicator elements were verified effective to indicate the heat reservoir under the overburden,which can be used in the exploration and prediction of geothermal resources.