闽南沿海地区钻孔实测热流值及深部温度预测  

Measured Heat Flow Value of Drilling and Deep Tempetature PrediCtion in Coastal Areas of Southern Fujian

作　　者：许益青[1] Xu Yiqing(South Fujian Geological Party , Zhang zhou,363000)

机构地区：[1]福建省闽南地质大队

出　　处：《福建地质》2019年第3期216-226,共11页Geology of Fujian

基　　金：福建省广义地质项目“福建省深部地热资源潜力调查评价”(项目编码:20140207)

摘　　要：依据近年来在闽南沿海地区陆续施工的5口千米钻孔的系统测温数据和岩石样品实测热导率、生热率,对钻孔所在地区地温梯度、热流值进行计算,同时根据一维稳态模型对深孔可能钻遇温度进行了预测。5口千米钻孔地温梯度为17.0~30.1℃/km,平均20.3℃/km,略低于大陆地区平均值(25~30℃/km);岩石热导率为2.95~3.20W/m·K,平均为3.11W/m·K;放射性生热率为2.52~2.97μW/m^3;计算的大地热流为54.06~96.02mW/m^2,平均为63.2mW/m^2,略低于全球大陆地区热流平均值65mW/m^2。利用岩石热导率、生热率和热流值数值,计算出钻孔深部12条可能的温度分布剖面。计算结果表明,超深井于2000m垂直深度上的温度为51~84℃;4000m垂直深度上的温度为78~142℃;理论上,只要深部的水文地质条件满足,是可以取得具有开发利用价值的地热流体,但从干热岩勘察开发角度出发,其勘察深度以5~6km为宜,同时为了避免浅部地下水径流的干扰,钻孔位置宜选择远离断裂或者取断裂的下盘位置。According to the system tempetature measurement data of drilling(5 km) and the measured thermal conductivity and heat generation rate of rock samples in the coastal areas of southern fujian in recent years, calculating the geothermal gradient、heat flow value, then according to one-dimensional stability the state model to predict the tempetature of deep drilling as well. The geothermal gradient of drilling is between 17.0-30.1℃/km, and the average geothermal gradient is about 20.3℃/km, which is slightly lower than the continental average(25-30℃/km);The thermal conductivity of rock is 2.95-3.20 W/m.K, the average thermal conductivity is 3.11 W/m.K;the radioactive heat generation rate is between 2.52 and 2.97 uW/m3;The calculated geothermal heat flow is between 54.06-96.02 mW/m2, and the average value is 63.2 mW/m2. It is slightly lower than the average heat flux of 65 mW/m2 in the global mainland. At the same time, using the thermal conductivity, heat generation rate and heat flow value of the rock, distributing 12 possible temperature profiles in the deep drilling. Results show that the temperature at the vertical depth of 2000 m is between 51-84℃;the temperature at the vertical depth of 4000 m will be between 78-142℃;Theoretically, as long as the deep hydrogeological conditions are met(appropriate part and depth)), it is possible to obtain geothermal fluids with development and utilization value, but from the perspective of dry hot rock exploration and development(theoretical temperature is at least 150℃), the survey depth is 5-6 km, and in order to avoid shallow groundwater runoff For interference, the location of the hole should be chosen to be away from the fracture or the position of the lower plate.

关 键 词：千米钻孔 地温梯度 热流 深部温度 干热岩 闽南沿海 

分 类 号：P314[天文地球—固体地球物理学]