199results about "Detection using electron/nuclear magnetic resonance" patented technology

The invention relates to the technical field of underground magnetic resonance detection, in particular to a multi-scale underground nuclear magnetic resonance detection signal denoising method and system. Comprising the following steps: acquiring underground nuclear magnetic signal data, and converting the underground nuclear magnetic signal data into an underground nuclear magnetic signal spectrogram; an encoder is adopted to extract multi-scale features from the underground nuclear magnetic signal spectrogram by dynamically adjusting the size of a convolution kernel, important information features of the multi-scale features are enhanced through a self-attention mechanism, and the multi-scale features are compressed to a potential space after being subjected to residual denoising to form real signals; generating a forged signal from the low-dimensional noise vector in the potential space by adopting a generator; the authenticity of the forged signal is judged by a discriminator and fed back to a generator, and the generator adjusts own parameters according to the feedback, so that the forged signal is close to a real signal; and a de-noised signal is obtained by recovering the space structure of the forged signal through the decoder. The method does not need pure signal pairing, is suitable for a complex underground nuclear magnetic detection environment, and improves the signal quality and the detection precision.

The invention belongs to the technical field of geophysical exploration, and relates to an underground water magnetic resonance longitudinal relaxation time detection method, which comprises the following steps: laying a magnetic resonance detection coil on the ground, fixing a short emission time, changing a current amplitude, emitting a plurality of short pulses, and collecting a short pulse observation signal generated by each short pulse; fixing a long emission time, re-emitting a series of long pulses with different current amplitudes, and collecting a long pulse observation signal generated by each long pulse; inverting the short pulse observation signal to obtain water content and transverse relaxation time distribution of underground water at different depths; and taking the water content and the transverse relaxation time distribution of the underground water at different depths as prior data of Bayesian inversion, and analyzing the long pulse observation signal by adopting Bayesian inversion to obtain longitudinal relaxation time distribution. According to the invention, a complex excitation sequence form is not needed, and a longitudinal relaxation signal of a short relaxation sample with a fast attenuation speed can be captured. The method is suitable for a high-power scene of field ground magnetic resonance detection.

The invention provides a ground nuclear magnetic resonance underground water inversion method and device, equipment and a storage medium. The method comprises the following steps: acquiring a ground detection nuclear magnetic resonance observation data envelope, a ground nuclear magnetic resonance forward modeling data envelope signal and an initial inversion model space parameter; mapping the space parameters of the initial inversion model in a preset range to obtain the updating parameters of the current iteration model; wherein the preset range is a numerical range meeting hydrogeological significance; constructing a ground nuclear magnetic resonance inversion objective function according to ground detection nuclear magnetic resonance observation data envelope, ground nuclear magnetic resonance forward modeling data envelope signals and current iteration model updating parameters; the ground nuclear magnetic resonance inversion objective function is solved through a quasi-Newton method, and updating parameters of a next-round iteration model are obtained; and if the difference value between the current-round iteration model updating parameter and the next-round model updating parameter is smaller than a preset error, taking the next-round model updating parameter as an inversion result. The accuracy of an inversion result can be improved.

The invention belongs to the technical field of geophysical exploration, and relates to a ground magnetic resonance real-time active noise reduction device and method, and the device comprises a detection coil which is used for collecting a nuclear magnetic signal after noise cancellation; the reference coil is used for collecting environmental noise, is coplanar with the detection coil and is placed at a position far away from the detection coil; the noise counteracting coil is placed above the detection coil in an overlapping manner; and the FPGA module is used for receiving the nuclear magnetic signal acquired by the detection coil after noise cancellation and the environmental noise acquired by the reference coil, and introducing correspondingly changing current into the noise cancellation coil according to the environmental noise so as to generate a changing magnetic field, so that the detection coil induces a cancellation response which has the same amplitude as the noise of the detection coil and is opposite to the noise of the detection coil in phase. According to the invention, the noise can be suppressed in real time at the source end of the instrument, and the anti-interference and weak signal detection capabilities of the ground magnetic resonance instrument in a complex electromagnetic environment are remarkably enhanced.

The invention belongs to the technical field of geophysical methods, and particularly discloses a method and system for extracting transient electromagnetic signals through ground nuclear magnetic resonance. The method comprises the following steps: periodically transmitting nuclear magnetic resonance excitation pulses to an underground medium, and extracting nuclear magnetic resonance turn-off pulses as transient electromagnetic excitation signals at the turn-off stage of each nuclear magnetic resonance excitation pulse; after each nuclear magnetic resonance excitation pulse is turned off, detecting a transient electromagnetic response signal; and when the last nuclear magnetic resonance excitation pulse is turned off, collecting a nuclear magnetic resonance response signal. According to the invention, the high-energy turn-off pulse is directly extracted as the transient electromagnetic excitation signal in the turn-off stage of the nuclear magnetic resonance excitation pulse, so that the overall signal utilization efficiency and excitation capability of the system are remarkably improved.

The invention relates to the field of field groundwater magnetic resonance detection methods, in particular to an augmentation system and method for field groundwater magnetic resonance detection small sample data. Comprising a generation network configured to receive random noise and generate augmented data based on the random noise; the discrimination network comprises a time domain discrimination network and a frequency domain discrimination network; the generative network and the time domain discrimination network form a first discrimination channel, the generative network and the frequency domain discrimination network form a second discrimination channel, and in the second discrimination channel, augmented data generated by the generative network and the noisy data are jointly input into the frequency domain discrimination network; the frequency domain discrimination network is used for discriminating whether the source of input data is a generation network or noisy data in a frequency domain. According to the method, a magnetic resonance detection small sample noisy data set is established, and multi-scale features in an amplitude spectrum and a phase spectrum are captured through the frequency domain discrimination network; the collaborative driving generation network generates a high-quality sample which is close to small sample noisy data in waveform form and spectral characteristics.

The invention discloses a laboratory adsorption gas calculation method based on isothermal adsorption-nuclear magnetic resonance combined measurement, and relates to the technical field of exploration geophysics. According to the invention, on the basis of isothermal adsorption-nuclear magnetic resonance combined measurement experiment, 23MHz nuclear magnetic resonance experiment is utilized; nuclear magnetic signal conversion of bound water-adsorbed state methane is carried out through nuclear magnetic resonance T2 spectrums of coal rocks with different water saturations and T2 spectrums measured through a coal rock isothermal adsorption-nuclear magnetic resonance combined measurement experiment to obtain the hydrogen content of the adsorbed state methane, then the amount of substance of the adsorbed state methane is obtained, and finally the volume of the adsorbed state methane is obtained. The method comprises the following steps: firstly, measuring and determining the content of bound water in the coal rock by adopting a 25mm sample tube and the current minimum nuclear magnetism callback interval, then carrying out bound water-adsorbed gas nuclear magnetism signal conversion on the sample tube used in an isothermal adsorption-nuclear magnetism combined measurement experiment to obtain the hydrogen content of the adsorbed gas, further obtaining the amount of substance of the adsorbed gas, and finally obtaining the volume of the adsorbed gas.

A computer-implemented method is provided. The computer-implemented method can include receiving one or more input NMR measurements at a first neural network; transforming the one or more input NMR measurements to a predicted pore throat size distribution or one or more predicted pore throat size parameters; receiving the predicted pore throat size distribution or the one or more predicted pore throat size parameters at a second neural network; transforming the predicted pore throat size distribution or the one or more predicted pore throat size parameters to a predicted NMR T2 distribution or one or more predicted NMR T2 parameters; and applying one or more physics based equations to the predicted NMR T2 distribution or the one or more predicted NMR T2 parameters to forward model the predicted NMR T2 distribution or the one or more predicted NMR T2 parameters to one or more simulated NMR measurements.

The invention relates to the technical field of nuclear magnetic resonance logging, aims to solve the problem that a method for jointly correcting a nuclear magnetic resonance logging T2 spectrum by integrating multiple factors does not exist at present, and provides a gas-containing shale nuclear magnetic resonance relaxation time spectrum correction method, a storage medium and a device. The method comprises the steps of obtaining target layer information; determining a T2 spectrum correction position; factors influencing the difference between the nuclear magnetic porosity and the conventional logging porosity are analyzed, and the influence of the factors on the nuclear magnetic resonance logging T2 spectrum is corrected according to the factors; respectively fitting each spectrum peak of the T2 spectrum through a Gaussian distribution curve, completing correction of each factor on the spectrum peak, and obtaining a final corrected nuclear magnetic offset T2 spectrum; superposing the porosity components of the corrected T2 spectrum Gaussian distributions of the fluid peaks at the corresponding distribution points to obtain corrected effective porosity and total porosity; according to the invention, automatic correction of the nuclear magnetic resonance logging T2 spectrum can be realized.

The present invention provides a functional simulation test device for nuclear magnetic resonance (NMR) logging electronic circuits. This device can replace the probe of an NMR logging instrument to perform reliability testing of electronic circuit sections. Compared with physical logging instrument probes, this device has smaller size, adjustable parameters, and adjustable test modes. It can simulate downhole NMR probe parameters to enable real-time reliability testing of electronic circuits. The device has four test functions, including single excitation testing, active excitation acquisition testing, controlled source excitation acquisition testing, and simulated probe testing. The device can interface with any NMR logging system to perform functional testing of the NMR system's electronic circuits.

The present application provides a kind of shale oil oil saturation measurement method, device, storage medium and electronic equipment, belong to petroleum exploration technical field.The shale oil oil saturation measurement method includes: obtaining two-dimensional nuclear magnetic T1-T2 spectrum, the two-dimensional nuclear magnetic T1-T2 spectrum is using the first pulse sequence of multiple waiting time, fluid distribution in the field core object is identified based on the two-dimensional nuclear magnetic T1-T2 spectrum, and the distribution characteristics of multiple core fluids are obtained.Based on the distribution characteristics of various core fluids, the oil saturation of various core fluids is calculated according to the preset saturation calculation model to obtain the oil saturation of shale oil.The oiliness can be qualitatively and quantitatively evaluated, the oil saturation can be accurately calculated, the oiliness can be quantitatively evaluated, and the well site rapid interpretation and evaluation can be realized.

The present invention discloses a method for effectively disassembling a nuclear magnetic resonance relaxation time spectrum, comprising the following steps: S1, constructing a probability density function of pores and caves according to the distribution characteristics of pores and caves in a core nuclear magnetic resonance T2 spectrum; S2, setting the sum of the nuclear magnetic spectrum areas to 1, randomly generating n data points within the interval of pore distribution, and dividing all the data points into multiple data sets by screening peak values; S3, calculating a likelihood function; S4, calculating a priori probability that each data point belongs to a pore or a cave; S5, updating various parameters in an iterative method using the priori probability; and S6, calculating a new logarithmic likelihood based on the updated parameters, and updating the expected E in the iterative method. p and E v , expected E p and E v Repeat steps S2 to S5 until the convergence condition is met and the iteration is terminated. The present invention combines nuclear magnetic resonance testing with an iterative method to decompose the nuclear magnetic resonance spectrum, thereby improving the accuracy of the spectral shape distribution.

The invention relates to a dual-transmit-receive multiplexing dual-frequency while-drilling nuclear magnetic logging module which comprises a probe framework, a first permanent magnet, a second permanent magnet, a first transmit-receive multiplexing coil, a second transmit-receive multiplexing coil, a first inverter circuit, a first compensation circuit, a first energy discharge circuit, a second inverter circuit, a second compensation circuit and a second energy discharge circuit. Wherein the first permanent magnet and the second permanent magnet are symmetrically arranged at two ends of the probe framework; the first transceiving multiplexing coil and the second transceiving multiplexing coil are symmetrically wound on the probe framework; the first compensation circuit is connected with the first transceiving multiplexing coil and the first energy discharge circuit, and the first energy discharge circuit is connected with the first full-bridge inverter circuit; the second compensation circuit is connected with a second transmit-receive multiplexing coil, the second compensation circuit is connected with a second energy discharge circuit, and the second energy discharge circuit is connected with a second full-bridge inverter circuit.

The present disclosure relates to a method that includes generating a first pulse at a first position along a geological formation with a plurality of antennae, wherein the first pulse comprises a Carr-Purcell-Meiboom-Gill (CPMG) sequence, and wherein each antenna of the plurality of antennae is configured to generate NMR data via transmitting and receiving pulses into the geological formation.

NMR-based lithium measuring and monitoring downhole tools and methods measure at least one lithium concentration of a fluid in a borehole and / or a surrounding formation of the borehole, wherein the downhole tool has an NMR sensor having a magnet-coil geometry with at least one magnet and a RF coil tuned to match a Larmor frequency of a nucleus of lithium. The downhole tools and methods acquire an NMR-based lithium concentration measurement of a fluid at a sensitive region within the wellbore and / or formation that is defined by the magnet-coil geometry of the NMR sensor and determine a lithium concentration of the fluid at the sensitive region based on the acquired NMR-based lithium concentration measurement. The downhole tools and methods may interpret an acquired signal based on relaxation distributions of total acquired signals, wherein the acquired signal is indicative of the acquired NMR-based lithium concentration measurement and separate a lithium signal from confounding signals deriving from other non-lithium nuclei based on the interpretated acquired signal.

This application discloses a well-seismic analysis system, method, and equipment based on a tight sandstone geomechanical coupled lithofacies system, relating to the field of tight sandstone oil and gas extraction analysis. The system employs a four-element composite triangular diagram method in its classification model construction module to construct a geomechanical coupled lithofacies classification model for tight sandstone reservoirs based on information data. The integration module performs geomechanical coupled lithofacies classification and integrates multi-type lithofacies prediction results at the single-well level based on element difference data. The analysis and determination module, based on a well-seismic collaborative three-dimensional model of the tight sandstone reservoir's geomechanical coupled lithofacies, performs feature extraction, lithofacies classification feedback adjustment, and seismic attribute mapping of the geomechanical coupled lithofacies to determine the distribution information data of the tight sandstone geomechanical coupled lithofacies. This application can determine the heterogeneous distribution law of rock mechanics and geostress characteristics in tight sandstone reservoirs, providing a basis for improving the extraction efficiency of tight sandstone oil and gas.

A method of determining a ratio of hydrogen to methane produced from a partially depleted shale gas reservoir comprising an organic nanopore system, an inorganic pore system, and a micro-fracture system, and housing stored hydrogen, comprises: obtaining a core sample from the reservoir, and subjecting the core sample to 1H Nuclear Magnetic Resonance (NMR) testing to obtain respective T2 and T1-T2 relaxation times for methane and for hydrogen in each one of the organic nanopore system, the inorganic pore system, and the fracture system.

The invention discloses an underground formation current injection electrode. The electrode comprises an upper connecting assembly, an electrode body, a lower connecting assembly, an upper multi-core cable and a lower multi-core cable, the upper multi-core cable penetrates through a plurality of mutually isolated holes in the upper connecting assembly, and the lower multi-core cable penetrates through a plurality of mutually isolated holes in the lower connecting assembly; the upper multi-core cable penetrates through a wire passing space arranged in the electrode body and is connected with the lower multi-core cable; the upper multi-core cable comprises a plurality of upper cable leads, and at least one upper cable lead is conducted with the electrode body; and the wire passing space is filled with an insulating medium. The electrode disclosed by the invention is simple in structure, convenient to construct, good in insulativity and high in safety and feasibility.

The present application belongs to the field of magnetic resonance signal noise filtering, specifically a sparse denoising method for ground magnetic resonance signals using a combined dictionary, which divides the magnetic resonance signal into frequency bands to reconstruct the power frequency harmonic components, and eliminates the power frequency harmonics from the magnetic resonance signal to obtain a power frequency-free signal; a trajectory matrix is ​​constructed using a Gaussian random matrix. Z , using the power frequency signal to construct the trajectory matrix Y , trajectory matrix Z Take the front K After column normalization, the initial dictionary is obtained D , trajectory matrix Y As original samples used to construct sparse coefficient matrix X ; Complete the initial dictionary through K-SVD dictionary learning D and the sparse coefficient matrix X The updated dictionary and sparse coefficient matrix are used to reconstruct the trajectory matrix to obtain the trajectory matrix W ; Take the trajectory matrix W The first row of is used to obtain a pure magnetic resonance signal, which can effectively remove the MRS signal noise in complex electromagnetic interference scenarios under the condition of a single signal acquisition.

The invention relates to the field of geophysical exploration, in particular to a nuclear magnetic logging data inversion system and method based on semi-supervised adversarial learning. Comprising a T2 spectrum reconstructor which is used for training by adopting a label logging data set to obtain a nonlinear mapping relation between a spin echo signal and a preliminary T2 spectrum, and processing a non-label logging data set according to the nonlinear mapping relation to generate a predicted T2 spectrum; the false label selector generates the confidence coefficient of the predicted T2 spectrum according to a false matching data set obtained by matching the actual spin echo signal with the predicted T2 spectrum and a labeled logging data set, and selects the predicted T2 spectrum as a false label according to the confidence coefficient; mixing a pseudo label and a predicted T2 spectrum, and taking the mixture, a label logging data set and a non-label logging data set as a training set of a T2 spectrum reconstructor; and the T2 spectrum reconstructor is trained by the training set to obtain a nonlinear mapping relation between the actual spin echo signal and the predicted T2 spectrum. According to the invention, high-precision and high-efficiency intelligent nuclear magnetic logging data T2 spectrum inversion under a limited label condition is realized.

Methods and systems herein may perform nuclear magnetic resonance measurements, and nuclear magnetic resonance tools, the method and systems comprising: acquiring, using an NMR sensor a first NMR signal from a volume in a subterranean region, wherein the first NMR signal is acquired using a first acquisition window. Further, acquiring, using the NMR sensor a second NMR signal from a volume in the subterranean region, wherein the second NMR signal is acquired using a second acquisition window different from the first acquisition window, wherein the first NMR signal and the second NMR signal form an NMR relaxation data; determining, using the first NMR signal and the second NMR signal, a correction term. Finally, the correction term may be used to acquire a corrected relaxation data set.

The present application discloses a method, device and computing equipment for determining the lower limit of effective reservoir physical properties. The method includes: obtaining a first transverse relaxation time spectrum of any measurement point obtained by performing nuclear magnetic resonance logging on the target formation; calculating the first effective porosity of the measurement point based on the first transverse relaxation time spectrum of the measurement point; extracting the second transverse relaxation time spectrum of the invading mud from the first transverse relaxation time spectrum of the measurement point, and calculating the second effective porosity of the measurement point based on the second transverse relaxation time spectrum; establishing a first intersection diagram of the first effective porosity and the second effective porosity based on the first effective porosity and the second effective porosity of different measurement points; determining the inflection point of the first intersection diagram, and using the first effective porosity corresponding to the inflection point as the lower limit of the effective porosity of the target formation. This solution can improve the accuracy of determining the lower limit of effective reservoir physical properties, lower the data threshold, and improve the efficiency of determining the lower limit of effective reservoir physical properties.

The present application relates to the technical field of geophysical signal processing and analysis, in particular to a tunnel magnetic resonance and transient electromagnetic joint inversion method, comprising: using a magnetic resonance and transient electromagnetic joint instrument, placing it at a tunnel face for detection, and obtaining observation data of a water-bearing structure in front of the tunnel face; using a Markov chain Monte Carlo algorithm to invert the collected data, obtaining stratum resistivity, water content distribution in front of the tunnel face, and interface position information of each layer, and probability distribution of these inversion parameters; while inverting and interpreting resistivity and water content information in front of the tunnel face, the uncertainty of the inversion result and the result of correlation analysis are given; finally, the resistivity and water content information distribution is given according to probability, which provides early warning guidance for tunnel engineering safety development.

A method for automatically determining an NMR pulse sequence for use in downhole NMR measurements, such as NMR logging while drilling measurements, includes receiving a set of expected NMR measurements and evaluating the received set of expected NMR measurements using a bilevel optimization to determine a pulse sequence for the downhole NMR measurement.

Systems and techniques are provided for determining a time zero echo of a nuclear magnetic resonance (NMR) sequence. An example method includes obtaining, via an NMR tool in a borehole, echo waveforms associated with refocusing pulses and a free induction decay (FID) waveform associated with an excitation pulse; determining echo values based on the echo waveforms and an apparent time-zero echo value based on the FID waveform, the apparent time-zero echo value representing a time zero echo; applying a correction factor to the apparent time-zero echo value to yield a corrected time zero echo value; and determining a spectrum associated with a sample based on an inversion performed on the corrected time zero echo values and the set of echo values before or after a conversion of the corrected time zero echo value and the set of echo values to porosity units, the conversion of the corrected time zero echo value and the set of echo values being based on one or more conversion factors.

The present disclosure provides a phase-controlled excitation downhole nuclear magnetic resonance imaging device and method which relate to the technical fields of downhole nuclear magnetic resonance imaging devices and methods, and achieve high-resolution imaging for an underground target by utilizing a plurality of array antenna units and a phase-controlled array technology. The array antenna units are uniformly arranged around an array antenna frame, and each antenna unit is capable of achieving independent transmission and collection. A transmission phase of each antenna unit is controlled by adopting a phase control technology, the positioning excitation of a transmission pulse is achieved according to a co-phase stacking principle, and thus, the imaging resolution is further improved. The present disclosure has the advantages of high resolution and high efficiency and is suitable for the field of underground exploration. The application of this method will provide a more accurate and reliable imaging result for underground exploration and provide an important technical support for resource exploration and development.

The application discloses a magnetic resonance signal denoising method combining a shaping Prony algorithm and a spatial prediction filter. Three-dimensional coordinate axis parameters are determined, and a spatial adaptive prediction filter structure is constructed. After data preparation is performed on received noisy signal data of multiple measuring points, a three-dimensional data body is established, Prony decomposition is performed on signal data in the three-dimensional data body by using a Prony algorithm, a shaping regularization method is introduced to solve a least square value, Prony transformation values of the noisy signal of the measuring points and spatial prediction filter coefficient values corresponding to the measuring points are obtained. A pure signal of a target measuring point is predicted and approximated by using Prony components of adjacent measuring points and the spatial prediction filter coefficient values, and suppression of random noise of the noisy signal of the target measuring point is realized. By using the method, coil laying work is reduced, detection efficiency is improved, random noise can be further effectively suppressed, complex effective signals are protected, and the signal-to-noise ratio of the magnetic resonance signal is improved.

The application discloses a nuclear magnetic resonance well logging multi-TW multi-TE observation data joint inversion method and device, and the method comprises the following steps: generating a plurality of groups of first echo train data according to nuclear magnetic resonance multi-TW multi-TE well logging data; constructing a joint equation based on the plurality of groups of first echo train data, and recombining the first echo train data into second echo train data; and constructing a signal matrix based on the second echo train data to perform joint inversion on the second echo train data. According to the method, different echo train data obtained in the multi-TW multi-TE mode is recombined, a joint inversion result of a plurality of echo data is obtained through a new joint inversion method, and finally, the multi-solution problem is eliminated.

This application relates to the field of geophysical exploration technology and provides a high-precision nuclear magnetic resonance (NMR) detection method for organic pollution. The method includes: transmitting a DC pulse P1; applying an amplitude-sweeping AC pulse AFP1 after turning off the DC pulse P1; turning off the amplitude-sweeping AC pulse AFP1 and transmitting a DC pulse P2; after turning off the DC pulse P2, applying an adiabatic half-wave pulse AHP1 and acquiring a first induced voltage signal; applying an adiabatic half-wave pulse AHP2 at the moment after turning off the adiabatic half-wave pulse AHP1 and acquiring a second induced voltage signal; applying an amplitude-sweeping AC pulse AFP2 after turning off the adiabatic half-wave pulse AHP2, and repeatedly applying the amplitude-sweeping AC pulse AFP2 after each time it is turned off, acquiring a third induced voltage signal. This application can selectively suppress groundwater signals and enhance the sensitivity of organic pollution signals.