The influence of directional structure on water yield characteristics of shallow geothermal wells: Pathways for rural revitalization in Zhangjiachuan
向形构造对浅层地热井涌水量特征的影响——基于助力张家川县乡村振兴路径实践

摘要

张家川县位于甘肃省天水市东北部，拥有丰富的地热资源，是该省地热勘探的理想区域。地质构造作为精准勘查地热田的重要步骤，是调查一个地区地热资源最基本的数据。然而，天水地区的相关研究仍相对有限：地热资源数据极为匮乏，且未能准确反映当地地热田的特征。为弥补这一不足，基于“地热+乡村振兴”示范工程路径，走进张家川县马鹿镇、恭门镇，分析该区域的地形地貌特征。结合研究区现有的地质资料、浅层地热现状，分析了新的地热田涌水量异常的原因，并在此基础上讨论了向形蓄水构造对浅层地热井涌水量特征的影响。研究表明：（1）F1压性断层是研究区主要的控热构造，F2~F4张性断层是研究区主要导水构造，距断层<100m区域涌水量提升2倍。（2）灵台村井紧邻F4断层分布，灵台村与马鹿镇卫生院井涌水量均达10m³/h，马鹿镇政府井涌水量显著偏低。马鹿镇政府区域第四系松散层不含水，较于其他两地热开采潜力较弱；灵台村及马鹿镇卫生院区域第四系松散层富水性强，地下水补给稳定。（3）钻井涌水量与断裂（裂隙带）的空间关联性为井位越靠近断裂（裂隙带），涌水量越大；反之，远离断裂（裂隙带）的井位，涌水量则相对较小，潜力较小。

Abstract

Zhangjiachuan County, located in the northeastern part of Tianshui City, Gansu Province, is rich in geothermal resources and constitutes a favorable prospect for geothermal exploration in the province. Geological structure serves as a critical step for precise geothermal field assessment, providing fundamental data for investigating regional geothermal resources. However, research in the Tianshui area is relatively limited, and available geothermal data are scarce, making it difficult to characterize the local geothermal fields accurately. To address this gap, following the demonstration project path of “Geothermal Energy + Rural Revitalization” field investigations were conducted in Malu Town and Gongmen Town of Zhangjiachuan County to analyze regional topographic and geomorphic characteristics. By integrating existing geological data and the current state of shallow geothermal resources in the study area, this study analyzes the causes of anomalous water yield in newly identified geothermal fields and discusses the influence of synclinal water-bearing structures on the water yield characteristics of shallow geothermal wells. The findings indicate: (1) The F1 compressive fault is the primary structure controlling heat distribution in the study area, while the F2~F4 tensile faults serve as the main water-conducting structures. Within 100 meters of these faults, the water yield increases approximately twofold. (2) The Lingtaicun well, located adjacent to the F4 fault, and the Malu Town Health Center well both achieve a water yield of 10 m³/h, whereas the yield from the Malu Town Government well is significantly lower. This is attributed to the absence of water in the Quaternary loose layers at the Malu Town Government site, indicating lower geothermal potential compared to the other two locations, where the Quaternary loose layers exhibit strong water richness and stable groundwater recharge. (3) A spatial correlation exists between well water yield and proximity to faults or fracture zones: wells closer to these structures demonstrate higher yields, whereas those farther away show relatively lower yields and reduced potential.