Application Of Audio Magnetotelluric Sounding In The Geothermal Field

Geothermal resources as a new energy, comparison to fossil energy like oil, gas,coal and nuclear energy that extensive use of human.geothermal resources is the cleanand renewable energy. it’s easy to exploitation, ease of application, and noenvironmental pollution,and many other advantages. it’s achieved good economic,social and environmental benefits, has a broad application prospects. But the means ofexploration methods and interpretation of geothermal resources is still no substantialimprovement,and traditional exploration methods have been insufficient to meet themission of exploration stage, so how to improve the efficiency of geothermalresources exploration is currently an urgent problem.Audio magnetotelluric sounding (referred to as AMT) is based on the principleof magnetotelluric sounding, study for the distribution of the natural electromagneticfield on the ground floor, a geophysical method to study the resistivity distribution ofthe rocks and minerals that underground. In geothermal exploration AMT is arelatively simple way,and be used very extensive. Application exploration methods ofAMT can effectively delineate the distribution of underground water, the thickness ofthe covering layer and the position of the hot source.This paper mainly focus on audio magnetotelluric sounding application results ingeothermal exploration, starting from the theoretical basis of AMT and the formationmechanism of geothermal fields, use the forward model to validation the theory oftheAMT, and comparison the different exploration ofAMT method to verify the effectiveness and some place that need for improvement.the hot water in the Underground will resistivity decreases of the thermalreservoirs, low resistivity anomaly is the important symbol to identify the geothermalresources, so the DC resistivity is the mainly method for geothermal resourcesexploration in the past, but with the burial depth of the underground water constantlyadded, the resistivity differences of the underground water is more obvious than thepast that performance at the surface,then the DC resistivity method is difficult toobserve the differences in the resistivity of the ground water that deeply buried. AMTeffectively compensate the lack of exploration depth of the DC resistivity method,thedistribution of apparent resistivity section get from AMT inversion interpretation wasnot only to reflect the faults and the distribution of the depth of stratigraphic space,Onsome conditions, can also be inferred temperature conditions deep geothermal fields,making the underground geothermal resources exploration becomes more efficient.Through research showed that: In the case of geological information andexploration purposes and clear audio magnetotelluric method in the exploration aspectof fracture zones and faults geothermal fields can play a good effect, through thedistribution of subsurface resistivity anomaly analysis, a good grasp of thedistribution of the underground geothermal reservoir storage conditions and thermalspace. With this stage, the occurrence of geothermal resources increasing depth,making the surface can be collected underground anomalies weakened theeffectiveness of conventional exploration methods significantly reduced, andtherefore, the use of audio magnetotelluric sounding method, combined with theknown exploration target areas of geological data and other data for a comprehensiveexplanation effective identification of geothermal fields buried deep underground,underground the hot water reserves and geothermal reservoir structure model is thekey to the exploration of geothermal fields.