河北汤泉地热田地温场分布及其控制因素研究

汤泉位于河北省遵化市西北部,为山前丘陵地貌,地热资源丰富。本文对汤泉地热田内分布的诸多基岩热水井进行了钻孔测温,利用测温结果对该地热田地温场分布特征及控制因素进行了研究。研究发现:钻孔温度明显受地下水流的影响,绝大部分测温井表现为对流传热特征,个别表现为传导为主的传热特征;地温异常区域位于汤泉福泉宫和疗养院一带,异常中心呈两极分布,地热异常中心50 m埋深水温为51~54℃,100 m埋深水温可达60~67℃;该地热系统中地热水系地下水在深循环过程中,在正常的大地热流背景下被围岩逐渐加热所致;由花岗岩隔水底板构造形态所形成的隐伏盆地,构成了福泉宫至疗养院一带的蓄水构造;由于断裂构造切割花岗岩体,造成深部的热流沿断裂上升,混合并加热赋存于福泉宫至疗养院一带蓄水构造中的片麻岩裂隙水,形成该地段的地热异常现象;福泉宫地区和疗养院地区片麻岩含水层裂隙发育,使得深部热量能够快速到达浅部地层,并在浅部出现局部异常高温;汤泉地热田片麻岩热储层地热流体属于含岩盐地层溶滤的陆相沉积水,主要来源于大气降水。

Temperature distribution and controlling factors of the Tangquan geothermal field in Hebei Province

Abstract: Located in the northwest of Zunhua City of Hebei Province, Tangquan is characterized by hilly landscape and rich geothermal resources. In this paper, the authors studied the borehole data of many bedrock thermal wells (water wells) in the study area, and investigated the distribution characteristics and controlling factors of the geothermal field. The results show that borehole temperature is significantly affected by groundwater flow, and the vast majority of temperature wells are characterized by convective heat transfer, with a few temperature wells characterized dominantly by heat transfer conduction. The geothermal anomaly center of the study area is located in the area from Tangquan Fuquan Palace to the sanatorium, and the anomaly center exhibits bipolar distribution; the temperature of water at the depth of 50m in the geothermal anomaly center is about 51~54°C, and that at the depth of 100m is up to 60~67°C. The geothermal water of the geothermal system is caused by gradual heating action of surrounding rocks under the normal heat flow background in the process of deep circulation of groundwater. The water storage structure from Fuquan Palace to the sanitarium is formed by a buried basin with granite confining floor. Because faults cut through monolithic granite body, and cause the upward migration of the heat flux of the deep rock along the fault, whereas the heat flux is mixed with fissure water of the gneisses and is concentrated in the area from Fuquan Palace to the sanatorium. Because the gneiss fractures the aquifer in Fuquan Palace area and sanitarium area, the deep heat can quickly reach the shallow strata and give rise to local abnormal high temperature in the shallow part. The geothermal fluid belongs to continental sedimentary water that is formed in the strata with dissolved salt brine, and is mainly derived from meteoric water.