摘要
陕西眉县汤峪地热田储量丰富,但经过长期开采,现有地热井水温度和出水量逐年下降,因此亟需寻找新的潜在地热资源。区内已知地热井受断裂控制明显,故研究此处深部断裂展布对于潜在地热资源的探究具有重要现实意义。受方法本身限制和地形影响,研究区难以进行传统地质路线调查或大规模工程以探究控热断裂,因此本文优选基于穿透性的土壤氡气测量与可控源音频大地电磁的新技术方法组合探测隐伏断裂,进而圈定研究区潜在地热资源。基于实测的地表土壤氡浓度异常数据和CSAMT反演提供的地下电性结构模型,在验证已知断裂的基础上,新推断隐伏断裂6条,预测潜在地热区2处,并建立了汤峪地热田概念模型。结果表明,隐伏断裂处的土壤氡浓度远高于区域背景值,CSAMT反演视电阻率结果显示其位于低阻破碎带,圈定的潜在地热区分别位于剖面450-750 m和850-1150 m范围内,深度约250-300 m。本次研究认为,地热田整体位于低阻且土壤氡异常值大于区域背景值3倍的区域,研究结果可为该地区后续潜在地热资源的可持续开发利用提供借鉴。
Despite abundant geothermal reserves of the Tangyu geothermal field in Meixian County,Shaanxi Province,long-term ex-ploitation has decreased the water temperatures and yields of its existing geothermal wells year by year.Hence,there is an urgent need to explore new potential geothermal resources in the geothermal field.Since the known geothermal wells in the geothermal field are sig-nificantly controlled by faults,investigating the deep fault propagation holds critical significance for exploring the geothermal field's po-tential geothermal resources.Due to the method limitations and the topographic influence,identifying thermal control faults through conventional geological route investigation or large-scale engineering is not applicable to the geothermal field.Therefore,a new techni-cal method combining the penetrating soil radon measurement and the controlled source audio magnetotelluric(CSAMT)method was employed in this study to find concealed faults and delineate potential geothermal areas.Based on the measured surface soil radon con-centration anomaly data and the subsurface electrical structure model derived from the CSAMT data inversion,this study inferred six new concealed faults on the basis of corroborating the known faults,predicted two potential geothermal areas,and built a conceptual model for the Tangyu geothermal field.As revealed by the results,the soil radon concentrations at concealed faults are much higher than the regional background value,and the concealed faults are located in the low-resistivity fracture zones as indicated by the appar-ent resistivity results based on CSAMT data inversion.Besides,the two potential geothermal areas spread from 450-750 m and 850-1150 m on the profile,respectively,at depths of approximately 250-300 m.This study concludes that the geothermal field resides in a low-resistivity region with soil radon anomalies three times the regional background value.The results of this study provide a reference for the subsequent sustainable production and utilization of potent
作者
薛东旭
刘诚
郭发
王俊
徐多勋
杨生飞
张沛
XUE Dong-Xu;LIU Cheng;GUO Fa;WANG Jun;XU Duo-Xun;YANG Sheng-Fei;ZHANG Pei(Xi'an Center of Mineral Resources Survey,China Geological Survey,Xi'an710100,China;School of Geophysics and Information Technology,China University of Geosciences(Beijing),Beijing100083,China)
出处
《物探与化探》
CAS
北大核心
2023年第5期1169-1178,共10页
Geophysical and Geochemical Exploration
基金
中国地质调查局国土空间生态地质调查及修复项目“西安城市群周边健康地质调查试点”(DD20211574)。
