综合地球物理方法在阜新市四合地区地热资源普查中的应用

Abstract

阜新市四合地区是地热资源勘查开发的空白区。为查明地热资源赋存状况，本次工作采用重力勘探、磁力勘探、可控源音频大地电磁测深、大地电场岩性探测等多种方法进行了综合地球物理推断解释。结果表明：项目区存在2条北东向断裂F1、F2和1条北西向断裂F3，这些断裂共同控制了区内地热地质条件；项目区发育两套热储层，上部为侏罗–白垩系义县组玄武岩、安山岩，下部为中元古界蓟县系雾迷山组白云岩。项目区南部为地热勘探靶区，面积12.05 km2；其上部热储层顶板埋深700~1400 m，顶板温度25℃~44℃，下部热储层顶板埋深1100~1800 m，顶板温度36℃~56℃。最终在勘探靶区内地热地质条件有利的部位设计了2眼勘探井。综合地球物理勘探成果有效地避免了单一方法的多解性，为下一步钻探工作的开展提供了重要的科学依据。 The Sihe area of Fuxin city is a blank area of exploration and development of geothermal resources. In order to investigate the occurrence and formation of geothermal resources, several methods, such as gravity exploration, magnetic exploration, CSAMT and the land electrotelluric lithological detection technique are applied in the exploration area. The comprehensive analysis results show that there are two faults with NE direction (named F1, F2) and one fault with NW direction (named F3) which together control the geological conditions of geothermal resources, and the geothermal reservoiris are divided into two main layer groups: the upper one is basalt and esite reservoir of Yixian formation of Jurassic-Cretaceous, and the lower one is dolomite reservoir of Mesoproterozoic Wumishan formation of Jixian. Geothermal exploration target is located in the south of the project site with the area 12.05 km2; and the depth of the upper heat stratum layer roof is 700 - 1400 m with the temperature of 25˚C - 44˚C, while the depth of the lower heat stratum layer roof is 1100 - 1800 m with the temperature of 36˚C - 56˚C. Based on the above results, two investigation wells have been designed at the location of favorable geological conditions in the exploration area. It shows that the multiple solutions by the single method can be effectively avoided through the results of integral geophysical survey which could provide an important scientific basis for further drilling work.