5 results about "Time domain electromagnetics" patented technology

The application discloses a semi-airborne full-time electromagnetic forward method based on an Octree grid, which performs spatial discretization on time-domain Maxwell equations, thereby effectively reducing unknowns of equations to be solved. For full-time electromagnetic field numerical simulation, the application combines the high calculation precision of the second-order backward Euler method with the high OFF-Time calculation efficiency of the model reduction algorithm, adopts the second-order BDF and the model reduction algorithm to respectively solve ON-Time and OFF-Time time-domain control equations, forms a joint algorithm to realize simulation of semi-airborne time-domain electromagnetic full-time response, and finally completes the forward calculation process. Through numerical simulation verification, in the full-time transient electromagnetic forward process, the application can keep small occupied memory and also has higher calculation efficiency, and the calculation precision is not lower than that of other methods.

The application relates to a time-domain electromagnetic space-time double-gradient resistivity imaging method, device, computer equipment, computer readable storage medium and computer program product. The method comprises the following steps: acquiring transient electromagnetic method data to be processed, wherein the data to be processed comprises electric field component attenuation data of m*n measuring points, and a far zone condition is met between the m*n measuring points and a long wire source; acquiring a spatial gradient expression of apparent resistivity and a time gradient expression of apparent resistivity; performing finite difference fusion based on the spatial gradient expression of resistivity and the time gradient expression of apparent resistivity to obtain a gradient resistivity expression; and generating a resistivity distribution map of a subsurface medium according to the data to be processed and the gradient resistivity expression. The abnormal body boundary description accuracy is improved.

The present disclosure belongs to the technical field of geophysical exploration signal processing, and particularly relates to a time-domain electromagnetic polarization parameter extraction method based on an improved physical guided neural network, comprising generating a sample set; constructing a loss function constrained by physical information; using the sample set, minimizing the loss function, and using an improved whale optimization algorithm to optimize the hyperparameters of the neural network to obtain a time-domain electromagnetic polarization parameter neural network inversion model; wherein the improved whale optimization algorithm introduces chaotic mapping to generate an initial population in the initialization stage, introduces a dynamic opposite learning strategy in the bubble net attack stage, and introduces an adaptive t-distribution disturbance variation in the search prey stage; obtaining measured data and preprocessing the same, using the time-domain electromagnetic polarization parameter neural network inversion model to process the preprocessed measured data, and extracting polarization medium model parameters. The method improves the accuracy and robustness of polarization parameter interpretation.

The application belongs to the technical field of petroleum physical exploration, and particularly discloses a wellbore electric source time-domain electromagnetic measurement device and method. The device comprises a ground collection system, a cable, a remote transmission short section, an array electric source receiving sensor and a transmitting device. The ground collection system is connected with the remote transmission short section through the cable. The remote transmission short section is connected with the array electric source receiving sensor. The array electric source receiving sensor is connected with the transmitting device. The measurement mode of electric source excitation and array electric source receiving is adopted, the manufacturing process difficulty of three-dimensional magnetic source in the limited space of the wellbore is reduced, the problem of difficult quick shutdown of the multi-turn coil is solved, and the ultra-long detection of the radial geological information beside the well is realized.

This invention discloses a time-domain electromagnetic data removal method based on continuous wavelet transform, belonging to the field of time-domain electromagnetic noise processing technology. The method includes: acquiring accelerated transient electromagnetic signals; processing and superimposing averaging methods for accelerated transient electromagnetic signals; continuously performing time-frequency transform on the superimposed "total field" signal to obtain a wavelet coefficient matrix; performing dual filtering on the wavelet coefficients, including frequency filtering and amplitude filtering; performing continuous inverse time-frequency transform on the filtered wavelet coefficients to reconstruct the time-domain signal; applying amplitude enhancement processing to the reconstructed signal; and performing Gaussian smoothing processing on the enhanced time-domain signal to facilitate feature recognition. This invention is based on GPU-accelerated continuous wavelet transform + fast convolution. Wavelet transform has multi-scale analysis capabilities, realizing multi-scale decomposition of the signal in the time-frequency domain. Combined with band filtering and amplitude filtering, it performs targeted noise suppression, accurately suppressing specific frequency noise such as power frequency interference and harmonics.