重庆市温塘峡背斜地热资源特征

Characteristics of geothermal resources in Wentang Gorge anticline of Chongqing

温塘峡背斜是华蓥山帚状穹褶束中的背斜之一,地热水资源丰富,地热显示主要表现为天然温泉和人工温泉2类。通过统计和分析背斜两翼地热钻井的水量、水质和含水层资料,发现该构造主要热储含水层为嘉陵江组四段和二段,次要热储含水层为嘉陵江组三段和一段。水化学类型以硫酸盐型为主,但两翼有所不同,镁钙离子当量浓度比小于1,说明地热水化学成分主要来源于灰岩含水层。水质和水量受地质构造作用控制。温塘峡背斜具备热储盖层、热储层和下部热储隔热隔水层的层状热储结构特征,热储温度表现为西翼和东翼相当。物探测井数据显示,1700~2000 m深度处热储温度在26.42~51.7℃之间,且自北向南略有升高。研究成果可为温塘峡地热水资源进一步勘查开发提供参考和指导。

The Wentang Gorge anticline is one of the anticlines in the broom-shaped dome pleats of Huaying Mountain,with abundant geothermal water resources of natural hot springs and artificial hot springs.Through statistics and analysis of the water quantity,water quality and aquifers of geothermal drillings on both sides of the anticline,the authors have identified that its main thermal storage aquifers are Member 2 and Member 4 of Jialingjiang Formation,and its secondary thermal storage aquifers are Member 1 and Member 3 of Jialingjiang Formation.The main hydrochemical type is sulfate type,but the conditions in the two wings of the anticline are different.The equivalent concentration ratio of magnesium to calcium ions is less than 1,which indicates that the chemical composition of the geothermal water is mainly from limestone aquifer.The water quality and quantity were controlled by the geological structure.The Wentang Gorge anticline has the characteristic of layered structure which includes thermal reservoir cap rocks,thermal reservoir and lower thermal reservoir insulation and confining bed,and the thermal storage temperatures for the two wings of the anticline are similar.The thermal storage temperature is between 26.42℃and 51.7℃at 1700-2000 m depth according to the geophysical logging data,with an increasing trend from north to south.This research would provide some references and guide for further exploration and exploitation of thermal water resources in Wentang Gorge.