综合地球物理勘探在齐齐哈尔地区低温地热系统调查中的应用——以HLD1井为例

Application in geothermal survey of low temperature system by integrated geophysical exploration in the Qiqihar area:take the well HLD1 as an example

随着我国"蓝天保卫战"打响,以及快速经济社会发展对清洁能源的需求急剧增加,地热资源因资源量巨大、分布广泛、清洁、可再生、利用率较高等优点,逐渐成为人们关注的热点.本文针对齐齐哈尔龙安桥地区的地热资源开展综合地球物理调查研究,方法包括有可控源音频大地电磁测深、大地电磁测深与反射地震勘探,通过对地热能控热要素——盖层、热储层、热源与导热通道的综合分析,查明了控热要素的空间配置关系,确立了该地区地热系统的成因模式,为该区低温地热资源调查提供有益的指导.通过研究发现,盖层主要为白垩系嫩江组与明水组的泥岩层,盖层厚度大,其中以嫩江组为主的低阻盖层主体埋深范围620~1020 m;热储层主要为白垩系泉头组、青山口组和姚家组的砂岩层,热储层厚度中等,主要埋深范围1050~1350 m;热源——盆地下部与基底的花岗岩、花岗斑岩等酸性岩体富含放射性元素,其衰变生热,以及下部幔源热向上热传导产生的热量;导热通道为热储层内部及下部断裂构造,这些断裂为热量的传导及热液的运移提供了运输通道.最后提出了该区的低温地热系统的成因模式为"层控热盖热储-岩体放射生热与地幔热共同供热-热传导与断裂通道共同导热"的热水系统成因模式.

With the implementation of "defense the blue sky" and the rapid growth economic and social needs, the demand for clean energy is increasing rapidly. Geothermal resources have gradually become the focus due to the advantages of huge resources, wide distribution, clean, renewable and high utilization rate. In this paper, integrated geophysical exploration in geothermal survey were carried out in Longanqiao area of Qiqihar, including CSAMT, MT and reflection seismic exploration. Based on the comprehensive analysis of heat controlling elements of geothermal energy-caprock, thermal reservoir, heat source and heat channel, the relationship of heat controlling elements is found out, and the genetic model of geothermal system in this study area is established, which can provide useful guidance for the investigation of low-temperature geothermal resources in this area. Some results are as follows. Both Cretaceous Nenjiang Formation and Cretaceous Mingshui formation are mainly caprocks, and their thicknesses are large, such as the main buried depth of Nenjiang Formation is about 620~1020 m. The thermal reservoirs are mainly composed of sandstones in Cretaceous Quantou Formation, Qingshankou Formation and Yaojia Formation. The thicknesses of thermal reservoirs are medium, and its buried depth is from 1050 m to 1350 m. Heat source: the geothermal energy are from the heat by the decay of radioactive elements in acid rock mass, including granite and granite porphyry in the lower part and basement of the basin, and mantle heat through heat conduction. The heat conduction channels are the fault structures in and below the thermal reservoirs, which can provide transport channels for heat energy and hydrothermal fluid. Finally, the genetic model of the low-temperature geothermal system in this area is proposed,which is a hot water system model of "the strata controlling the thermal caprocks and the thermal reservoirs-thermal energy from both the rock mass radiative heat and the mantle heatheat transfer by the conventional heat conduction and the fracture structure".