广域电磁法在长平盆地白垩系地层地热资源评价中应用

Wide Field Electromagnetic Method is Applied in the Evaluation of Cretaceous Stratigraphic Geothermal Resources in Changping Basin

对工作范围区处于长平盆地下白垩系地层,首次利用广域电磁法探测中深部3km范围内地层结构及构造发育情况,初步评价范围区内地热资源。主要成果为:①盖层为白垩系上统戴家坪中段泥质砂岩,埋深-210~-300m;下段为巨厚层块状花岗质砾岩,埋深-800~-1050m。白垩系下统神皇山组上段,埋深-1200~-1420m。②储热层为白垩系下统神皇山组下段,含灰质砾岩,钙泥质胶结,埋深-1550~-1700m。沉积盆地底部为冷家溪群板岩,埋深-1800~-2030m以下。③重新确定F10、F12两断层平面位置。④本区具有较好地热盖层,白垩系整套地层为红色碎屑岩,含水性差,厚度大,地热资源具有较好保存条件,具有地热开发潜力。

The working area is located in the underground Cretaceous formation of Changping Basin,and the wide-area electromagnetic method is used for thefirst time to detect the stratigraphic structure and tectonic development within 3km of the middle and deep part,and the geothermal resources in the scope area are preliminarily evaluated.The results are mainly reflected in:①the cover layer is argillaceous sandstone in the middle section of Daijiaping of the Cretaceous system,and the burial depth is-210~-300 m;The lower section is a huge thick layer of massive granite conglomerate,buried at a depth of-800~-1050 m.The upper section of the Cretaceous Lower Shenhuangshan Formation,buried at a depth of-1200~-1420 m.②The heat storage layer is the lower section of the Shenhuangshan Formation of the Cretaceous Lower System,containing gray conglomerate and calcium argillaceous cementation,burial depth-1550~-1700 m.The bottom of the sedimentary basin is the slate of the Lengjiaxi Group,and the burial depth is-1800~-2030 m.③Redetermine the plane position of F10 and F12 faults.④This area has a good geothermal cover layer,and the whole set of Cretaceous strata is red clastic rock,with poor water content and large thickness,and geothermal resources have better preservation conditions and potential for geothermal development.