| Jilin Province Changchun Jingyue Economic Development Zone is located in thevicinity of the Yishu basin, which stretches across two big tectonic units: Yishugraben and Songliao Basin. geothermal anomaly area of Jilin province belonged to theYishu basi. In recent years, geothermal resources are vigorously develop inShuangyang, Wanchang, Gu Dian Zi and Hua Pi factory where take use of thegeothermal energy to develop the business of bath and leisure vacation and achievedgood social and economic benefits. Yitong River connecting the Yishu graben andSongliao Basin has important development potential in Jingyue EconomicDevelopment Zone and the geothermal potential of this area has attracted a lot ofattention.CSAMT is an artificial source frequency domain sounding method, which isdeveloped to overcome the shortcomings of MT that the signal strength is weak. Withthe advantages of high signal-to-noise ratio and strong observation signal, CSAMThad achieved good results in deep prospecting and geothermal resource exploration..Aiming at the present situation of geothermal resource in Changchun City area,this paper firstly studies the theory of CSAMT, then through the establishment of twothree-layer geoelectric model to detect the detection depth of the method. Secondly,the spatial distribution of geological structure, formation, fault, hydro geological andgeothermal characteristics of the new city of Changchun is analyzed, and the formingconditions of the geothermal resources are studied. Finally, on the basis of fieldreconnaissance, combined with the regional geology and regional gravity andmagnetic data, regional electrical characteristics, according to the relationshipbetween the fracture and the water bearing formation configuration determined afavorable location.Field work were designed and completed six survey lines of CSAMT, there are2survey lines in East-West (labeled as line of3.5and4.5line),4survey lines inNorth-South(labeled as7,8,9and10lines from west to East), the total actualmeasurement points is288. Through the research of CSAMT Geothermal in the new city, the followingconclusions are drawn.:1、There is a North South fault zone in the research area, whose width is about500-600meters. Evidence is: the resistivity profile in East-West were showed and Thefault also exists on the geological analysis. the9line is in the belt, so the resistivity isvery low；2、There is a North West faults in study area. This is shown in7lines,8lines,9lines,10lines in NS and3.5lines,4.5line in EW；3、The study area may exist groundwater which is related to the deep faults andthe depth is about2500meters. The best location of the well is the composite part ofthe fracture in North South and North West；4、Through the establishment of two three-layer geoelectric model, analysisshows that at high frequency band, the apparent resistivity can correctly reflect thegeoelectric variations, while in the low frequency band, the apparent resistivity valuewas significantly higher than the given value of the initial model. serious distortioncan not accurately reflect the vertical change of the geoelectric section, but the wholestill can get the more consistent positive results；5、In the inversion of resistivity profile, the longitudinal changes of resistivityand the measured resistivity logging curve is consistent, which is proved that theinversion of resistivity profile is real, especially for the low frequency inversion.Namely the result of inversion depth>1500m is credible；6、According to the configuration and the relationship between fracture andaquifer, determine2favorable location. |
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