High resolution static frequency domain removed magnetotelluric method

Abstract

This invention discloses one large electromagnetic method with high resolution rate and to remove static frequency, which comprises the following steps: it comprises multiple collection devices onto explore areas with same electrode near public electrode point to get normal observation curve on each result; adding the near two points, three points to total points in same field to compute even value on time sequence data; suing the field vector for observation value for power spectrum and resistance estimation change rule; editing the static interference resistance to get the resistance; repeating the last step till all records are edited.

Description

technical field [0001] The invention relates to a geophysical prospecting method, in particular to a high-resolution destatic frequency domain magnetotelluric method. Background technique [0002] The magnetotelluric method is an important exploration geophysical method, which is mainly used in many fields such as energy, metal minerals, groundwater, engineering and marine resource exploration. The main observation device used in this method is to set a pair of static electric field observation electrodes on the surface of the area to be explored along the north-south and east-west directions or two other directions perpendicular to each other, two electrodes corresponding to the above two electric field observation electrodes and The magnetic probes perpendicular to each other, a magnetic probe in the vertical direction and a collection device connected with the above-mentioned electrodes and probes can measure the vertical changes of the underground medium, thereby bringin...

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Problems solved by technology

However, the frequency domain magnetotelluric method of this prior art has the following problems: when there is an inhomogeneous body on the surface near the observation electrode, due to the accumulation of charges on its contact surface under the action of the electromagnetic field, and the additional electric field generated by the accumulation of charges The surface electric field component of the plane electromagnetic wave caused by the distribution of the underground medium is changed. For different frequencies, the accumulated charge generated by the surface electric field on this interface is proportional to its electric field strength, so it will inevitably generate an additional electric field of the corresponding frequency. Due to the observation The relative position of the interface between the device and the inhomogeneous body is fixed during the observation period, so for all frequencies, the additional electric field generated by the respective electric field components is proportional to the corresponding surface electric field component, and this scaling factor is independent of frequency Constant (real number), so its influence is: to make the overall translation of the resistivity curve, that is, to produce a static effect

This effect can cause electrical false anomalies in horizontally continuous geoelectric geological bodies, and make the supposedly continuous geological bodies be divided into multiple units by longitudinal fractures, which brings insurmountable difficulties to processing, interpretation and comprehensive analysis. Contradict the fractures in the final data with the actual existence

In addition, in the existing correction methods, due to the limitations of known data, some actual geological structure phenomena will often be covered up due to excessive correction.

In addition, since conventional processing methods cannot eliminate static interference and are limited by computing power, in order to use calculation methods such as fast Fourier transform to save computing resources, frequency points evenly distributed on logarithmic coordinates are used in the selection of observation frequency points processing, which causes the defect of reduced vertical resolution

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