30 results about "Magnetotelluric sounding" patented technology

The invention discloses a geothermal abnormal point identification system based on remote sensing detection. The system comprises a data layer which collects thermal infrared remote sensing data, multispectral / hyperspectral remote sensing data, radar data, geological and topographic data, meteorological data and geophysical prospecting data; the processing layer is used for extracting key features, capturing dynamic changes of geothermal anomalies, distinguishing continuous geothermal anomalies and transient events, combining hyperspectral data and magnetotelluric sounding data, and constructing'earth surface-deep part 'associated features; the analysis layer is used for learning a diffusion rule of geothermal anomalies along a fault zone through a graph propagation model, taking a geothermal field heat conduction equation as a loss function constraint by utilizing a physical information neural network, jointly training a temperature field prediction model, constructing a deep three-dimensional geological structure based on gravity and geophysical prospecting data, and constructing a geologic structure model; constructing a geothermal anomaly detection model through the features provided by the processing layer to recognize geothermal anomaly points; and the output layer is used for generating a geothermal anomaly probability graph.

The embodiment of the invention relates to the technical field of earth exploration, and discloses a magnetotelluric observation method, device and equipment in any observation direction and a medium, and the method comprises the steps: collecting electromagnetic field data of an electromagnetic field observation channel in magnetotelluric sounding in an observation area, and carrying out the data processing, and obtaining first electromagnetic field frequency spectrum data; the electromagnetic field observation channels comprise at least one electric field observation channel and two magnetic field observation channels, and the arrangement direction of each electric field observation channel and the arrangement direction of each magnetic field observation channel are non-orthogonal; vector transformation correction is carried out on the first electromagnetic field spectrum data to obtain second electromagnetic field spectrum data, and the second electromagnetic field spectrum data is orthogonal electromagnetic field data under an orthogonal coordinate system; and calculating an impedance tensor based on the second electromagnetic field spectrum data according to the number of the electric field observation channels. According to the method disclosed by the invention, the problem that traditional magnetotelluric observation is limited by complex terrain or observation conditions can be solved, and the application range of the magnetotelluric observation method is expanded.

The invention relates to the technical field of geophysical exploration, in particular to an optimal selection method for an oil-gas structure favorable area of a low-exploration-degree area of a mountain-front thrust zone. The method comprises the following steps: selecting an oil and gas prospective area, carrying out surface geological survey based on a regional geological map, compiling a surface fracture structure outline map and determining a main structure trend; performing wavelet decomposition on the gravity data to determine a substrate fracture adaptation result; deploying a magnetotelluric sounding profile in a direction perpendicular to the structure to obtain an electrical model, and compiling a substrate fracture diagram; deploying a sounding profile and a wide-line two-dimensional seismic profile fixed low-resistance strip in a parallel structure trend; a base depth map is calibrated, and a hidden strike-slip fracture layout is tracked; performing mesh generation to calculate indexes, performing standardized assignment, and performing mean value gridding; and preferably selecting an oil-gas structure favorable area by combining a drilling gas content fixed boundary. By adopting the ground measurement and multi-geophysical technology, the method is low in cost, simple to operate, high in efficiency and adaptive to a low exploration area, the optimization accuracy is improved, and powerful technical support is provided for optimization of an oil-gas exploration target area.

The invention discloses a magnetotelluric sounding measurement method for multidirectional aggregation observation, and the method comprises the steps: building a novel device layout: designing a reasonable measurement point layout scheme according to geological features and electromagnetic response distribution; processing data and establishing an unstructured grid: acquiring an electromagnetic field component, completing data acquisition, and inputting the processed electromagnetic field data into an unstructured grid model; impedance tensor calculation: on the basis of the unstructured grid, performing impedance calculation by utilizing multi-component electromagnetic field data and combining an interpolation idea, and constructing an extended impedance tensor of an electromagnetic field component to obtain an impedance value component; and three-dimensional inversion and visualization: performing three-dimensional inversion through a vector finite element method to obtain an inversion result. According to the method, richer observation data are provided for deep geologic structure inversion.

The invention provides a magnetotelluric sounding data splicing processing method and a magnetotelluric sounding data splicing processing system. The magnetotelluric sounding data splicing processing method comprises the steps of (1) acquiring magnetotelluric sounding data corresponding to different measuring points of adjacent blocks and regional rock electrical parameter data; (2) performing quality inspection on the magnetotelluric sounding data; (3) evaluating and classifying the quality of the magnetotelluric sounding data; (4) performing standardization processing on the magnetotelluric sounding data; (5) preprocessing the magnetotelluric sounding data; (6) carrying out normalization processing on the magnetotelluric sounding data; (7) carrying out splicing processing on the magnetotelluric sounding data after normalization processing, carrying out data smooth transition on data in an overlapping region of adjacent blocks, and checking residual error distribution of the data before and after splicing; (8) carrying out joint inversion on the spliced data; and (9) analyzing the depth domain resistivity data volume. The method is reasonable in conception and can be applied to secondary contiguous processing of magnetotelluric data acquired in different periods of oil-gas exploration.

The invention discloses a two-dimensional inversion operation method, system and device for a magnetotelluric sounding profile, a medium and a product, relates to the technical field of magnetotelluric sounding exploration, and aims to solve the problem that existing inversion based on nonlinear conjugate gradients is highly dependent on an initial model. The method comprises the following steps: firstly, acquiring measured data including measured point measured kilometer network coordinates, apparent resistivity and phase data; a two-dimensional inversion profile with complete data of each measuring point is constructed according to linear projection, and data interference and distortion are eliminated through preprocessing; the method comprises the following steps: firstly, constructing a uniform half-space model, and carrying out two-dimensional nonlinear conjugate gradient TE mode inversion to obtain a rough two-dimensional resistivity model; and taking the rough model as an initial model, carrying out TM mode inversion to obtain a target two-dimensional resistivity model, and finally carrying out geological interpretation by combining rock physical property, geology and drilling geophysical prospecting data. According to the method, through a strategy of first TE and then TM, dependence of an initial model is reduced by means of a TE mode, resolution capability is improved by means of a TM mode, false anomalies are reduced, reliability of a target model can be improved, and accurate data support is provided for mineral exploration and deep geologic structure research.

The invention discloses a geomagnetic disturbance geoelectric field calculation method based on a block geoelectric structure, relates to the technical field of geomagnetic disturbance geoelectric field calculation, and solves the technical problem of low GIC calculation accuracy in complex geology. According to the method, in a macroscopic scale, a one-dimensional conductivity model is inverted by using long-period magnetotelluric sounding, and a regional structure framework is delimited by combining a geological map, so that the accuracy of a global electrical background is ensured; a three-dimensional electrical structure is constructed through audio magnetotelluric sounding in the mesoscale, a secondary geological unit is recognized, and the problem that a traditional model is insufficient in depicting transverse electrical differences is solved; in the microscopic scale, for a key area, high-density resistivity imaging and a controllable source audio magnetotelluric method are used for capturing a high-conductivity / low-resistance anomalous body, and fine modeling of a local area is achieved; according to the method, the geological complexity is mined through the multi-scale model, so that the calculation precision of the GIC is improved.

The present invention discloses a device for improving the grounding resistance in magnetotelluric sounding in desert areas, which relates to the technical field of magnetotelluric sounding. The device includes a water supply tank, a water supply ring cylinder, a ring cover and a sunshade. The water supply ring cylinder is configured to be placed in an electrode pit. The water supply ring cylinder includes an inner cylinder and an outer cylinder sleeved outside the inner cylinder. An annular space is formed between the inner cylinder and the outer cylinder, and an anti-blocking material is filled in the annular space. The inner cylinder is filled with a grounding filler, and electrodes are buried in the grounding filler. A plurality of water permeable holes are provided on the side wall of the inner cylinder. The ring cover covers the upper end port of the annular space, and the lower end of the annular space is closed. A water supply switch is provided at the bottom of the water supply tank, and the water supply switch is communicated with the annular space through a water pipe. The sunshade is used to cover above the water supply ring cylinder to shield the grounding filler. The device for improving the grounding resistance in magnetotelluric sounding in desert areas provided by the present invention can obtain a stable grounding resistance in an electrode pit with a conventional volume, reduce the construction cost and improve the work efficiency.

The invention discloses a karst landform area underground two-dimensional geological structure modeling method and system, and belongs to the technical field of geophysical exploration. Aiming at the problem of poor geological modeling precision caused by low signal-to-noise ratio, high physical property heterogeneity and lack of drilling data of seismic data in a karst landform area, the method comprises the following steps: acquiring electrical property, earthquake and geological multi-source information through magnetotelluric sounding, two-dimensional earthquake and shallow surface geological survey; processing is carried out by using the borehole-side sounding to constrain the electrical structure; the fracture is identified by integrating the difference between the electrical gradient band and the seismic wave group; for the deep area, utilizing an electrical marker bed and a seismic wave group to track the stratum, and for the shallow area, recovering the stratum form based on the earth surface occurrence and the drilling thickness; and evaluating whether the stratigraphic sequence and the thickness conform to a regional rule or not by blocks, and iteratively optimizing the model. According to the method, the modeling precision and reliability of the underground two-dimensional geological structure in the karst landform area can be remarkably improved, and the method is low in cost, easy and convenient to operate and suitable for low-exploration-degree areas.

The present invention provides a denoising method for non-stationary and non-linear magnetotelluric sounding signals, which relates to the technical field of geophysical exploration. The method includes obtaining magnetotelluric sounding signals from a magnetotelluric sounding instrument, selecting one channel from the obtained magnetotelluric sounding signals, denoising it, and repeating the above operations to perform denoising processing on the remaining obtained magnetotelluric sounding signals. By combining variational mode decomposition (VMD) and independent component analysis (ICA), the present invention realizes the denoising of magnetotelluric sounding signals from multiple perspectives of time-frequency domain and statistical characteristics. When the effective signal is interfered by non-stationary noise with high energy for a long time, this method can ensure the high quality of the reconstructed signal, effectively reduce the influence of artificial parameter selection, be robust to noise, and at the same time provide a clear physical explanation, overcoming the limitations of traditional denoising methods and providing a more reliable and accurate data processing means for the field of geophysical exploration.

This invention discloses a comprehensive prediction method for oil-uranium-hot dry rock-shale oil in sedimentary basins, belonging to the field of geological exploration technology. This method involves using effective geophysical methods to extract basic geological background information, constructing a three-dimensional spatial framework of the basin, clarifying the correlation between structures, strata, and igneous rocks, calculating the correlation coefficient and intercept of airborne gravity and magnetic anomalies, initially screening key target areas, extracting key information on energy resource accumulation / mineralization, performing two-dimensional or three-dimensional characterization of target geological bodies, combining magnetotelluric sounding inversion profiles with seismic and drilling data, adjusting core parameter settings, and overlaying oil-uranium-hot dry rock-shale oil resource accumulation / mineralization evaluation information to obtain comprehensive energy resource prediction results. This method can provide scientific and technical support for basic geological research on oil-uranium-hot dry rock-shale oil in sedimentary basins and provide comprehensive and reliable prediction of resources.

The invention relates to the technical field of audio magnetotelluric, in particular to an audio magnetotelluric probing data acquisition system which comprises a data acquisition end, a detection signal transmission line, a feedback transmission line and a processing end. In each unit module, each conductive contact is distributed with an identifier, and the processing module is used for detecting the conductive contact which is currently in a conducting state, taking the identifier of the conductive contact which is in the conducting state as a form indicator, and sending the form indicator to the processing end. And the processing end is used for determining the actual form of the detection signal transmission line according to the form indicator of each unit module, and determining the position coordinate of the data acquisition end according to the actual form. The method can effectively reduce the data distortion risk and error risk when the data acquisition end is used in a large scale, guarantees the accurate detection process, and provides a guarantee for the actual application process of audio magnetotelluric exploration.

This specification provides a magnetotelluric sounding evaluation method and system. The method is executed based on a processor of the magnetotelluric sounding evaluation system, and includes: obtaining historical geological data of a mining area, human activity information at multiple preset time points, and power equipment operation information at multiple preset time points; and obtaining multiple sets of original electromagnetic monitoring data; determining at least one set of electromagnetic monitoring spectra based on the human activity information at multiple preset time points, the power equipment operation information at multiple preset time points, and the multiple sets of original electromagnetic monitoring data; determining at least one set of mining geological evaluation information based on the at least one set of electromagnetic monitoring spectra; and determining a mining geological inference result from the at least one set of mining geological evaluation information based on the historical geological data of the mining area, the human activity information at multiple preset time points, and the power equipment operation information at multiple preset time points.

The application discloses a kind of karst landform area underground two-dimensional geological structure modeling method and system, belong to geophysical exploration technical field.For the problem that karst landform area seismic data signal-to-noise ratio is low, physical property is strong inhomogeneous, drilling data is deficient and leads to poor geological modeling precision, the present application obtains electrical property, seismic and geological multi-source information by magnetotelluric sounding, two-dimensional seismic and shallow surface geological survey;With well-by-side sounding constraint electrical property structure processing;Comprehensive electrical property gradient zone and seismic wave group difference identification fracture;Deep region is tracked stratum using electrical property marker layer and seismic wave group, and stratum morphology is restored based on surface occurrence and drilling thickness in shallow region;Whether stratum sequence and thickness meet regional rule is evaluated by block, and model is iteratively optimized.The present application can significantly improve the modeling precision and reliability of underground two-dimensional geological structure in karst landform area, and is low in cost, easy to operate, applicable to low exploration degree region.

The application belongs to the technical field of geophysical exploration, and relates to a magnetotelluric sounding data processing method and system based on compressed sensing, which comprises the following steps: acquiring four-component time domain data, constructing a sampling matrix A according to the plane coordinates of a collection station and a high-resolution grid of a target in a study area, constructing a sparse representation dictionary D, making a magnetotelluric target signal be represented as the product of the sparse representation dictionary D and a sparse coefficient X, solving the sparse coefficient X based on a compressed sensing optimization model, calculating a frequency domain signal on the high-resolution grid by using the sparse coefficient X obtained through iterative solving and the sparse representation dictionary D, obtaining reconstructed electromagnetic field frequency domain data, and modifying the reconstructed electromagnetic field frequency domain data by using Maxwell equation constraints. The application breaks through the Nyquist sampling limit by utilizing the frequency domain sparsity of magnetotelluric data, and solves the problems of low resolution, poor detail recovery and weak physical consistency of a traditional interpolation method, so that the underground geological structure information can be more accurately recovered.

The application discloses a kind of deep matter thermal state quantitative estimation method based on electrical structure model, first according to the magnetotelluric sounding data collected, establish the deep three-dimensional electrical structure model of study area;Again, according to the relationship between rock conductivity and its temperature, the relationship between the total conductivity and temperature of the upper mantle in solid mixed system and solid-melt mixed system is considered respectively, the quantitative relationship model of the total conductivity of the upper mantle and temperature, rock melting percentage content is established;Finally, according to the quantitative relationship model, the conductivity data measured by actual magnetotelluric is brought in, the rock melting percentage content and temperature in the scale range of the upper mantle are calculated, and the deep thermal structure model of exploration area is established.The application can directly obtain deep temperature and rock melting percentage content by combining the electrical structure model established by rock physics and magnetotelluric sounding.

The invention discloses a magnetotelluric sounding method and a magnetotelluric sounding system for geothermal exploration. The magnetotelluric sounding method comprises the following steps: acquiring magnetic field intensity and frequency characteristics of a working area; determining observation information of the magnetotelluric observation system according to the magnetic field intensity and frequency characteristics of the working area, and obtaining magnetotelluric data based on the observation information; performing correlation parameter comparative analysis on the preprocessed magnetotelluric data to obtain a correlation parameter statistical comparison result; and establishing a geoelectric model according to an inversion result based on the related parameter statistical result, and generating an address color release profile map according to the geoelectric model so as to perform geothermal resource detection. According to the invention, the problems of shallow exploration depth, low interpretation precision, large error and the like in the existing geothermal geology survey can be solved.

The present invention discloses a method for calculating real-time apparent resistivity of magnetotelluric sounding. A triple processing structure is adopted in an embedded MCU, which is divided into an interrupt processing function, a pre-processing thread, and a post-processing thread. The sliding accumulation processing method is used to separate the acquisition process from the processing. The acquisition process reads and writes data in the DMA acquisition mode, without occupying the processing time of the MCU. The MCU only processes the interrupt message forwarding for the acquisition process. The memory pool technology is used for the memory area receiving the acquired data, reducing the data area acquisition efficiency and increasing the continuity of the data area. Most of the processing time of the MCU can be used for the processing thread. The processing algorithm is also distributed in the pre-processing thread and the post-processing thread. The pre-processing thread is used to quickly respond to whether the acquired data meets the conditions and accumulate the data that meets the calculation conditions. The post-processing thread is used to calculate the final apparent resistivity data of magnetotelluric sounding.

The invention provides a three-dimensional seismic exploration method and system based on multi-source geological data fusion, and the method comprises the steps: carrying out the data standardization of obtained multi-source heterogeneous geological data of a target work area, and generating a standard data set; wherein the multi-source heterogeneous geological data comprises seismological observation data, drilling data and magnetotelluric sounding data; based on the seismic data and the logging data in the standard data set, feature correlation analysis is carried out through a pre-trained deep learning model to obtain a lithology sensitive factor data body, and the lithology sensitive factor data body is used for representing the response confidence coefficient of the seismic data to lithology change; and establishing an objective function of seismic and electromagnetic data joint inversion by taking the lithology sensitive factor data volume as a dynamic constraint, and obtaining comprehensive physical property data by solving the objective function, the comprehensive physical property data being used for constructing a three-dimensional geologic model. The method can improve the precision and reliability of seismic exploration.

The application provides a magnetotelluric sounding data splicing processing method and system, and the method comprises the following steps: (1) acquiring magnetotelluric sounding data and regional rock electrical property parameter data corresponding to different measuring points of adjacent blocks; (2) performing quality inspection on the magnetotelluric sounding data; (3) performing quality evaluation and classification on the magnetotelluric sounding data; (4) performing standardization processing on the magnetotelluric sounding data; (5) performing pretreatment on the magnetotelluric sounding data; (6) performing normalization processing on the magnetotelluric sounding data; (7) performing splicing processing on the normalized magnetotelluric sounding data, performing data smoothing transition on the data of the overlapping area of adjacent blocks, and performing inspection on the residual distribution of the data before and after splicing; (8) performing joint inversion on the spliced data; and (9) performing analysis on the depth domain resistivity data body. The application has reasonable design and can be applied to secondary continuous processing of magnetotelluric data collected in different periods of oil and gas exploration.

The present application relates to the technical field of geophysical exploration, and discloses a deep learning inversion method and system for magnetotelluric sounding, comprising: constructing a trained magnetotelluric one-dimensional inversion model; converting measured apparent resistivity and measured phase data into interpolated apparent resistivity and interpolated phase data, using a Savitzky-Golay filter to construct a target multi-window Savitzky-Golay filter set to obtain smoothed apparent resistivity and smoothed phase data, and constructing an inversion apparent resistivity-phase data set based on the smoothed apparent resistivity and smoothed phase data; inputting the inversion apparent resistivity-phase data set into the trained magnetotelluric one-dimensional inversion model to obtain a corresponding inversion resistivity geoelectric model set, and obtaining a target resistivity geoelectric model based on the inversion resistivity geoelectric model set; the present application solves the problems of low accuracy and poor practicability in the existing deep learning inversion method for magnetotelluric sounding.

This application relates to the field of geological exploration, particularly to methods, apparatus, electronic equipment, and storage media for well site target area surveying in deep geothermal reservoirs. The method includes: acquiring gravity data of the area to be surveyed; determining buried hills and / or uplift zones based on the gravity data, and designating these zones as preferred target areas; determining the magnetotelluric signals of the preferred target areas using magnetotelluric sounding; and determining the electrical data of the preferred target areas based on the magnetotelluric signals. This application improves the efficiency of well site selection.

The invention provides a denoising method and system for human noise of a magnetotelluric sounding signal, and relates to the technical field of magnetotelluric sounding data processing. According to the method, linear trend removal and amplitude standardization preprocessing is carried out on multi-channel time sequence data, and decomposition parameter self-adaptive optimization is realized in combination with variational mode decomposition, envelope entropy evaluation and a sparrow search algorithm; a useful mode and a noise mode are distinguished by using permutation entropy, a Hankel matrix is constructed for the noisy mode, and de-noising is completed through singular value decomposition and matrix truncation reconstruction. The method can effectively identify and suppress human noise, and improve the signal-to-noise ratio and interpretation reliability of the magnetotelluric sounding signal.

The application discloses a method for intelligently selecting power spectrum of magnetotelluric sounding method based on deep learning classification, and specifically comprises the following steps: S1: segmenting MT electric field and magnetic field time series data collected in the field, calculating power spectrum of each time series, and obtaining MT sub-power spectrum; S2: respectively performing impedance estimation on all MT sub-power spectrum and total power spectrum after full stacking, and respectively calculating apparent resistivity and phase; S3: using apparent resistivity and phase after full stacking to perform Rhoplus inversion, and calculating fitting difference between resistivity and phase obtained by inversion and apparent resistivity and phase of the sub-power spectrum. The method for intelligently selecting power spectrum of magnetotelluric sounding method based on deep learning classification has the effects that in MT measured data processing, manpower cost can be greatly saved, uncertainty and randomness of manual selection of power spectrum can be avoided, and the influence of noise on impedance estimation of MT data can be effectively inhibited.

This application belongs to the field of geophysical exploration technology, specifically relating to a magnetotelluric sounding station layout optimization method and system based on sensitivity analysis. The method includes: establishing a three-dimensional subsurface structure model; integrating multi-source geological data to establish a three-dimensional subsurface structure model; discretizing the three-dimensional subsurface structure model into N grid cells, using the resistivity of each grid cell as the model parameter; constructing a parameter sensitivity matrix of the model parameters to the observation data; constructing a multi-objective optimization objective function; converting the multi-objective optimization objective function into a minimization objective function; and solving it using a non-dominated sorting genetic algorithm with an elitist strategy to obtain the optimal solution. This application changes the traditional method's reliance on the subjective experience and judgment of technical personnel, significantly improving the scientific rigor and consistency of station layout decisions.

The present invention belongs to the technical field of mineral exploration, and specifically relates to a prospecting method for gold deposits controlled by fault structures in alpine permafrost-covered areas. The prospecting method provided by the present invention is aimed at gold deposits controlled by fault structures in alpine permafrost-covered areas, and a set of working methods including selecting prospecting prospective areas, 1:25,000 stream sediment survey, collection and analysis of remote sensing images, field geological survey, magnetotelluric sounding and deep drilling verification is used. With the goal of gold deposits controlled by fault structures in alpine permafrost-covered areas, through reasonable design of prospecting methods, the specific ore-forming positions of specific gold deposits in the prospecting prospective areas are finally determined, that is, the most favorable positions for gold mineralization, achieving a breakthrough in prospecting for gold deposits controlled by fault structures in alpine permafrost-covered areas. The prospecting method provided by the present invention has the characteristics of being economical and practical, environmentally friendly, highly operable, and having good prospecting effects.

The invention discloses a salt lake low-resistance area magnetotelluric sounding observation duration adaptive regulation and control system and method, and relates to the technical field of geophysical exploration, and the method comprises the steps: selecting a measurement point before observation starting, collecting an electric field and geomagnetic time sequence in real time, calculating the change rate indexes of an electric field and a magnetic field, and obtaining the overall stability index of an electromagnetic field; establishing a first stable time period through threshold judgment, and starting observation pre-activation and interference source analysis; arranging a magnetic induction coil array based on the first stable time period, calculating electric field noise energy density and direction interference index in each direction, screening a low interference direction and locking a main observation direction; acquiring an electric field component in a main direction in real time, calculating effective electric field intensity, comparing the effective electric field intensity with a low-resistance penetration threshold value, judging the penetration capability, and determining whether to start a delay acquisition mechanism or not; comprehensively constructing an observation weighting factor, and correcting the final acquisition time; according to the method, the observation data quality and stability in the salt lake area low-resistance environment are effectively improved, and effective acquisition of deep electromagnetic response is ensured.

A controllable source audio frequency magnetotelluric sounding transmitting end electrode arrangement system and method belong to the technical field of electromagnetic prospecting, and particularly relate to the technical field of electromagnetic sounding electrode arrangement. The system and method solve the technical problem that the current CSAMT transmitting end electrode arrangement technology cannot simultaneously achieve the core target of "greatly reducing resistance and increasing current + zero field source distortion + high construction feasibility". The system and method comprise a main dipole unit and A-side and B-side distributed auxiliary electrode arrays. The main dipole unit is composed of A0 and B0 main transmitting electrodes. The A-side auxiliary electrode array is arranged in a direction away from the B0 along a dipole axis, the B-side auxiliary electrode array is arranged in a direction away from the A0 along the dipole axis, and the double-side arrays are completely symmetrical along the dipole center. All same-side electrodes are connected in parallel at an equal potential to a transmitter, and the transmitting current is in-phase and equal potential. The system and method only need short electrodes and artificial shallow pits for arrangement, the grounding resistance is greatly reduced, the transmitting current is steadily increased, and the ideal horizontal electric dipole field source characteristics are strictly guaranteed without field source distortion.

The application belongs to the technical field of geophysical exploration, and relates to a magnetotelluric sounding data processing method and system based on compressed sensing, which comprises the following steps: acquiring four-component time domain data, constructing a sampling matrix A according to the plane coordinates of a collection station and a high-resolution grid of a target in a study area, constructing a sparse representation dictionary D, making a magnetotelluric target signal be represented as the product of the sparse representation dictionary D and a sparse coefficient X, solving the sparse coefficient X based on a compressed sensing optimization model, calculating a frequency domain signal on the high-resolution grid by using the sparse coefficient X obtained through iterative solving and the sparse representation dictionary D, obtaining reconstructed electromagnetic field frequency domain data, and modifying the reconstructed electromagnetic field frequency domain data by using Maxwell equation constraints. The application breaks through the Nyquist sampling limit by using the frequency domain sparsity of magnetotelluric data, solves the problems of low resolution, poor detail recovery and weak physical consistency of a traditional interpolation method, and more accurately recovers underground geological structure information.

The present application relates to the field of geophysical exploration technology, in particular to a method for selecting favorable oil and gas structure area in low exploration degree area of piedmont thrust belt. The method comprises the following steps: selecting an oil and gas prospective area, conducting surface geological survey based on regional geological map, preparing surface fault structure outline map and determining main structure trend; wavelet decomposition of gravity data to determine the fitting result of basement fault; deploying magnetotelluric sounding profile perpendicular to the structure trend to obtain electrical property model and compile basement fault map; deploying sounding profile and wide line 2D seismic profile parallel to the structure trend to determine low resistance belt; calibrating the depth of the basement to compile the burial depth map, and tracking the hidden strike-slip fault to compile the distribution map; grid partitioning, standardization assignment, and mean grid; and combining with the gas content of the drilling to determine the boundary and select the favorable oil and gas structure area. The present application adopts surface measurement and multiple geophysical technologies, which is low in cost, simple in operation, high in efficiency, suitable for low exploration area, and can improve the selection accuracy and provide strong technical support for the selection of oil and gas exploration target area.