合肥市浅层地温场分布特征及影响因素分析

Analysis on distribution characteristics and influencing factors of shallow geothermal field in Hefei

通过对合肥市15个地温监测孔的长期观测,分析了该市浅层地温场的分布特征及其影响因素。研究结果表明:合肥市浅层地温场整体呈西低东高分布特征,区内恒温带平均温度在17.4℃左右,恒温带深度在12~32m左右,地温梯度在2.3~4.1℃之间。浅层地温场主要受地质构造控制,同时受地层岩性及地下水补径排条件影响。200m以浅岩性以泥岩、砂岩为主,胶结程度差,结构松散,且地下水贫乏,浅层地温能的开发利用适宜采用地埋管型地源热泵。

Based on a year-long survey of 15 geothermal observation holes in Hefei,a temperature monitoring curve and ground temperature distribution map were drawn.The distribution characteristics of the shallow geothermal field are westlow and east-high;the average temperature in the constant temperature zone is approximately 17.4℃;the depth of the constant temperature zone is approximately 12-32 m;and the geothermal gradient is between 2.3℃ and 4.1℃.Based on these findings,we believe that the shallow geothermal field is mainly controlled by the geological structure;but it is also affected by formation lithology,groundwater recharge,and discharge conditions.Specifically,the lithology from a depth of 200 m to the shallow lithology is composed of a sandstone-based mudstone with poor cementation and a loose structure,and the groundwater is poor.This indicates that the development and utilization of shallow geothermal energy is suitable for ground-source heat pumps with buried pipes.