青海省共和地区地热资源特征分析及利用研究

Study on the Characteristics and Utilization of Geothermal Resources in Gonghe Area, Qinghai Province

为有效实现青海省共和地区的地热资源利用,结合共和地区的地热地质条件,充分开展了地热资源的热储特征分析、地热流体化学特征分析和地热流体动态特征分析,并在此基础上,也进行了地热资源的开发利用研究。分析结果表明:共和地区的热储层主要有2层,即新生代下更新统粉细砂、中砂及含砾中粗砂孔隙型热储和新生代新近系砂岩、砂砾岩裂隙孔隙型热储,其中,新近系热储井口水温多在40℃~105℃之间,总体水温高,水量大;下更新统热储井口水温多在24.8℃~72.8℃之间,总体水温较低,局部地区可因地制宜开发利用。同时,在流体化学特征方面,水平向的矿化度总体上从北向南(盆地边缘到中心)逐渐增高,具有水质由好变差的规律,且水化学类型具由简单变为复杂的特征;垂直向的矿化度由低变高,水化学类型变化比较大,基本由简单变为复杂,具有明显的变化规律。另外,在地热流体动态特征方面,下更新统热储的水位最大变幅为0.32 m~0.75 m,温度最大变幅0.7℃~1.9℃;新近系热储水位最大变幅为0.12 m~0.19 m,温度最大变幅1.1℃~4.61℃。最后,共和地区的地热开发利用现状相对有限,但后续具有较大的开发潜力,可从地热供暖、温泉疗养及地热电站等方向实现地热资源的开发利用。

In order to effectively realize the utilization of geothermal resources in the Gonghe area of Qinghai Province, in combination with the geothermal geological conditions in the Gonghe area, the analysis of the thermal reservoir characteristics of geothermal resources, the analysis of the chemical characteristics of geothermal fluids and the analysis of the dynamic characteristics of geothermal fluids have been fully carried out, and on this basis, the research on the development and utilization of geothermal resources has also been carried out. The analysis results showed that there are mainly two thermal reservoirs in Gonghe area, namely Cenozoic lower Pleistocene silty fine sand, medium sand and gravel containing medium coarse sand pore type thermal reservoir and Cenozoic Neogene sandstone and glutenite fracture pore type thermal reservoir. Among them, the wellhead water temperature of Neogene thermal reservoir is mostly 40℃~105℃, and the overall water temperature is high and the water volume is large;The water temperature of the lower Pleistocene thermal reservoir well mouth is mostly between 24.8 ℃ and 72.8 ℃, and the overall water temperature is low, so local areas can be developed and utilized according to local conditions. At the same time, in terms of fluid chemical characteristics, the mineralization degree in the horizontal direction generally increases from north to south(from the edge of the basin to the center), with the law that the water quality changes from good to poor, and the hydrochemical type changes from simple to complex;The mineralization degree in the vertical direction changes from low to high, and the hydrochemical type changes greatly, basically from simple to complex, with obvious change rules. In addition, in terms of the dynamic characteristics of geothermal fluid, the maximum variation of water level and temperature of the Lower Pleistocene thermal reservoir is 0.32m~0.75m and 0.7℃~1.9℃ respectively;The maximum variation of the water level of the Neogene thermal reservoir is 0.12m~0.19m, and the maximum variation of the temperature is 1.1℃~4.61℃. Finally, the current situation of geothermal development and utilization in the Republic of China is relatively limited, but it has great development potential in the future. The development and utilization of geothermal resources can be realized from geothermal heating, hot spring recuperation and geothermal power stations.