327 results about "Relaxation (NMR)" patented technology

A method for separating liquid-like (T2e) from solid-like (T2G) 1H NMR transverse relaxation times in porous media uses novel pulse sequences together with a 1H NMR spectrometer optimized for geological core samples. The method is applied to obtain 1D T2 distributions and 2D T1-T2 maps in organic-rich chalks for quantification of liquid-like signal (micropore fluids, meso-macropore fluids, fluids dissolved in organic matter, and clay-bound water) and solid-like signal (kerogen, bitumen, and clay hydroxyls). The novel pulse sequences comprise a solid-echo, which detects more solid-like signal than an FID. The method is used for fluid typing in micro / meso-macro pores, clay mineral identification, determination of kerogen content, and quantification of solvent-extracted bitumen versus bitumen expelled from kerogen due to swelling from dissolved hydrocarbons. The method is used to quantify the asphaltene, resin, aromatic, and / or saturate content of bitumen in the rock.

The invention discloses a nuclear magnetic T2 spectrum correction method for a shale reservoir, and relates to the field of object detection, and the nuclear magnetic T2 spectrum correction method for the shale reservoir comprises the following steps: 1, determining the gas logging porosity, saturated water porosity and main mineral components of the shale reservoir; compared with the prior art, the method disclosed by the invention has the beneficial effects that a drying-saturated water-centrifugal two-dimensional nuclear magnetic resonance experiment is carried out, and signals of crystal water, clay bound water and hydroxyl in a sample are preliminarily identified; through inversion of organic matter signals in the dry sample, signals of movable water are further determined; the relation between the difference value among the gas logging porosity, the saturated water porosity and the nuclear magnetic porosity and different mineral contents is discussed, and particularly the remarkable influence of iron-containing minerals on the porosity difference value is discussed; by eliminating the influence of diffusion relaxation caused by the magnetic susceptibility difference, the T2 spectrum correction method based on the mineral magnetic susceptibility is established, and the T2 spectrum accuracy obtained through nuclear magnetic resonance measurement is improved.

The invention discloses an SERF atom magnetometer double-axis magnetic field detection method and device based on pulsed magnetic field modulation, relates to the technical field of magnetic field precision measurement, and compresses the action time of a modulation magnetic field additionally applied in the same unit period on a hot atom ensemble by replacing conventional continuous sinusoidal magnetic field modulation with pulsed magnetic field modulation. The pulse magnetic field with the duty ratio of d can reduce the spin exchange relaxation rate to 2d times of that of a conventional method under the same modulation amplitude and frequency, due to the fact that the spin exchange relaxation rate is effectively restrained, the collected polarizability response signal is obviously improved, and the polarizability response signal can be obtained through the pulse magnetic field with the duty ratio of d and the pulse magnetic field with the duty ratio of d. Low-relaxation-rate sensitivity-enhanced double-axis magnetic field measurement under a pulse modulation scheme is realized, the double-axis measurement sensitivity of a miniaturized SERF atom magnetometer is further improved, and the method has great significance in supporting leap-type development of a future array type extremely-weak magnetic imaging system and medical application thereof.

1H-NMR spectroscopic molecular markers are provided for identifying medical risk signatures such as SARS-CoV-2 infection, acute inflammation, or a cardiovascular risk condition. The markers use a combination of NMR intensity signals, including a Glyc signal from at least one N-acetyl (—NCOCH3) glycoprotein and an SPC signal from a choline head group (+N—(CH3)3) of a supramolecular phospholipids cluster (SPC) present in HDL and LDL lipoprotein subfractions. The Glyc signal is in a chemical shift region from #=2.00 ppm to #=2.20 ppm, and includes signals GlycA (2.00 ppm to 2.09 ppm) and GlycB (2.09 ppm to 2.2 ppm). The SPC signal is in a chemical shift region from #=3.20 ppm to #=3.30 ppm, and includes signals SPC1 (3.2 ppm to 3.235) ppm, SPC2 (3.235 ppm to 3.26 ppm), and SPC3 (3.26 ppm to 3.3 ppm). A system for identifying the markers is also provided.

The invention discloses a method for characterizing the pore size of the full pore diameter of shale based on combined measurement of a gravimetric method and NMR. The method comprises the following steps: drawing a curve that the pore distribution frequency of a rock sample changes along with the pore diameter; calculating the saturated water porosity of the rock sample based on the weight of the dried rock sample and the weight of the saturated rock sample; based on the saturated water porosity of the rock sample, converting the nuclear magnetic semaphore of the nuclear magnetic resonance T2 spectrum after saturation treatment of the rock sample into a porosity component; based on the porosity component, drawing a change curve of the porosity component and the porosity accumulated value along with the relaxation time T2 after saturation treatment of the rock sample; calculating a space-time conversion coefficient between the nuclear magnetic resonance relaxation time T2 value and the pore size; and based on the space-time conversion coefficient, drawing a full-aperture pore size result graph after saturation treatment of the rock sample on the basis of the change curve of the porosity component and the porosity accumulated value along with the relaxation time T2 after saturation treatment of the rock sample. The phenomenon that the measurement ranges of the pore sizes are overlapped does not exist through multiple simultaneous measurement means, and the obtained full-aperture pore size result is higher in precision.

The invention discloses a magnetic source positioning method based on a spin-exchange relaxation-free atom magnetometer, and aims to provide a high-precision brand-new solution for magnetic source positioning in a near-zero magnetic environment by performing physical modeling and least square estimation on space magnetic field distribution of a target magnetic source. The magnetometer is enabled to be simultaneously sensitive to a three-axis magnetic field, a light absorption detection method is utilized to ensure that complete three-axis magnetic field information is obtained, and the sensitivity of the three axes reaches fT / Hz1 / 2 (1fT = 10 <-15 > T) magnitude. In the positioning process, the target magnetic source is abstracted into a physical model of the magnetic dipole, and the space magnetic field information generated by the target magnetic source is obtained through the atom magnetometer, so that the long-term stability of the magnetic source positioning process and the high precision of the positioning result can be ensured in the zero magnetic environment; therefore, a high-precision magnetic positioning technical means with great potential is provided for various application scenes such as paleomagnetic sample testing and magnetic source positioning in medical research, and technical progress and application expansion in related fields are expected to be promoted.

The invention discloses an ultrahigh-sensitivity three-axis closed-loop spin exchange relaxation-free atom magnetometer, which expands the ultrahigh-sensitivity measurement capability of the atom magnetometer to three axes based on parameter modulation optimization and double detection light, fully inhibits transverse spin relaxation introduced by a modulation magnetic field, provides more high-quality information for weak magnetic measurement, and improves the measurement accuracy. Based on decoupled magnetic field information, a three-axis magnetic field sensitive to an atomic ensemble is locked to zero in real time, and closed-loop feedback quantity is used as magnetic field measurement information, so that the problems of nonlinear offset of a magnetometer calibration coefficient and cross-axis coupling crosstalk caused by magnetic field drift are fundamentally inhibited; the high anti-interference capability of the atom magnetometer in a complex magnetic field environment is enhanced, long-time stable measurement and magnetic field measurement precision of the atom magnetometer are guaranteed, sub-fT-level sensitivity and pT-level precision can be achieved on transverse double axes, and the atom magnetometer is suitable for the fields of extremely weak magnetic measurement testing, biomedical weak magnetic imaging and the like.

The invention discloses chemical mechanical polishing equipment, a polishing solution detection method, a polishing method and a medium. The chemical mechanical polishing apparatus includes: a polishing disk; the bearing head is used for polishing the wafer on the polishing disc; the liquid supply assembly is used for supplying polishing liquid to the bearing head, and the polishing liquid is distributed on the polishing surface of the polishing disc; the lifting check ring is arranged on the periphery of the polishing disc, a Helmholtz coil is arranged on the lifting check ring, the lifting check ring is provided with an avoiding position when polishing is stopped and a blocking position when polishing is conducted, and when the lifting check ring is located at the blocking position, the polishing surface of the polishing disc is located within the range of the Helmholtz coil so that a basic magnetic field can be formed on the polishing surface; the pulse generating arm is used for superposing a pulse magnetic field on the polishing liquid; and the magnetic field detection arm is arranged between the pulse generation arm and the bearing head and is used for detecting a nuclear magnetic resonance signal responding to the pulse magnetic field so as to determine the distribution condition of the polishing solution according to relaxation time data of hydrogen atoms reflected by the nuclear magnetic resonance signal.

The invention provides a method and device for calculating the electron spinning state of an iron-based biphase composite magnetic material, and relates to the technical field of magnetic materials. The method comprises the following steps: establishing a heterojunction model of a biphase composite magnetic material; according to the method, generalized gradient approximation in a density functional theory is adopted as an exchange-correlation functional, relaxation is carried out on atomic positions in a heterojunction model, so that the total energy of a system is the lowest, and geometric structure optimization is carried out on the heterojunction model; performing spin polarization calculation on the optimized heterojunction model to obtain spin upward state densities and spin downward state densities of different atoms in the heterojunction model, and analyzing electronic state distribution near a Fermi level; and quantitatively evaluating the magnetic characteristics of the heterojunction model according to the spin upward state density and the spin downward state density of each atom. According to the method, an interface magnetic coupling mechanism can be disclosed, and a theoretical basis can be provided for development of a high-performance magnetically controlled reactor iron core material.

The invention relates to a multi-principal element alloy local lattice distortion measurement method based on a synchrotron radiation X-ray atom pair distribution function, which comprises the following steps: preparing an experimental material, and collecting two-dimensional diffraction data by using synchrotron radiation high-energy X-rays; separating local and average structure information through an atom pair distribution function; and verifying local distortion causes by combining structure fitting and DFT supercell relaxation. According to the method, the accuracy of capturing the local distortion of the atomic scale can be improved, the integrity of statistical information of the local structure distortion of the quantitative characterization material can be fully supplemented, and high-precision measurement and quantitative analysis of dynamic distortion can be systematically realized.

The invention provides a quartz enhanced photoacoustic spectrometry detection system environment gas interference correction method which can be applied to the technical field of photoacoustic spectrometry gas detection. The method comprises the following steps: analyzing vibration-translation relaxation time and infrared absorption peak intensity of each gas to be detected; the to-be-detected gas with the vibration-translation relaxation time exceeding the time threshold value and the absorption peak intensity larger than the intensity threshold value is selected as comparison gas; dividing the laser of the comparison gas into a first laser beam and a second laser beam according to a preset proportion; using the first laser beam to excite a sound wave signal and detecting by a quartz tuning fork to generate a tuning fork electric signal; the second laser beam is enhanced and absorbed by a multi-reflection absorption cell and then is detected by a photoelectric detector to generate a light intensity electric signal; establishing a neural network model taking the tuning fork electric signal, the light intensity electric signal and the environment gas component vector as input and taking the to-be-detected gas concentration vector as output; and correcting the concentration of the to-be-detected gas under the interference of the environmental gas in real time through the trained neural network model.

The invention discloses a method for determining saturation and a nuclear magnetic T2 value of irreducible water produced by an ultra-low permeability reservoir. After a plunger sample is pretreated, basic parameters of the plunger sample are measured, the plunger sample is vacuumized, pressurized and saturated to simulate formation water, a nuclear magnetic resonance signal of the plunger sample is collected by using a low-field nuclear magnetic resonance relaxation analysis instrument and is inverted into a nuclear magnetic resonance T2 spectrum, the nuclear magnetic resonance porosity is obtained, and then according to the centrifugal pressure gradient, the magnetic resonance porosity is calculated. The method comprises the following steps: carrying out centrifugal experiment on a plunger sample under different centrifugal pressures by using a high-speed refrigerated centrifuge, obtaining the water saturation and nuclear magnetic resonance T2 spectrum of the plunger sample after each centrifugation, determining a relation curve between the centrifugal pressure and the water saturation, and obtaining the production irreducible water saturation and the limit irreducible water saturation after treatment by using a second-order derivation method, so as to obtain the production irreducible water saturation and the limit irreducible water saturation. And the accumulated T2 spectrum of the plunger sample when the water is completely contained is calibrated, so that the value range of the nuclear magnetic resonance T2 value of the real production irreducible water saturation is accurately obtained, and reservoir evaluation of an ultra-low permeability reservoir and oil-gas field development are facilitated.

The invention belongs to the technical field related to nanometer material testing, and discloses a magnetic nanoparticle relaxation time detection method and an environmental parameter detection method, and the method comprises the following steps: applying an excitation magnetic field around a to-be-detected target mixed with magnetic nanoparticles; obtaining magnetization response generated by the magnetic nanoparticles in any direction of the magnetic field plane, and obtaining phase lag corresponding to any order harmonic term of the magnetization response; according to the function relationship between the phase lag corresponding to any harmonic term and the Brown relaxation time of the magnetic nanoparticles, solving and obtaining the Brown relaxation time of the magnetic nanoparticles; wherein the function relationship comprises a correction term introduced by magnetic dipole interaction of the magnetic nanoparticles. The magnetic dipole interaction among the magnetic nanoparticles is introduced, relaxation time detection of particle space distribution under an external magnetic field is corrected, the interference of the magnetic dipole interaction on the magnetic nanoparticle Brown relaxation time detection process can be effectively reduced, and accurate estimation of the magnetic nanoparticle Brown relaxation time is realized.

The invention provides a shale oil nuclear magnetic resonance forward and reverse modeling method and device, and relates to the technical field of petroleum engineering and rock physics. The method comprises the following steps: acquiring a simulated nuclear magnetic resonance T2 spectrum of a saturated water state of a shale core according to first attribute data of the shale core and a T2 spectrum of pore size distribution conversion; according to the simulated nuclear magnetic resonance T2 spectrum in the saturated water state, obtaining shale core nuclear magnetic resonance T2 spectrums of crude oil with different viscosities by utilizing viscosity differences of the crude oil at different temperatures and nuclear magnetic resonance relaxation characteristics of oil and water; performing forward modeling on the nuclear magnetic resonance T2 spectrum of the shale core to obtain an echo string signal, and adding noise to the echo string signal to obtain echo string attenuation data; and performing inversion on the echo string attenuation data to obtain the nuclear magnetic resonance simulation T2 spectrum of the shale core with different crude oil viscosities, which contains noise and data processing errors. The device executes the method. According to the method and the device provided by the embodiment of the invention, relatively real data can be obtained.

The invention discloses a relaxation time evaluation method and system applied to a radiation band modeling process, and solves the technical problem that the distribution and relaxation time of high-energy particles in a radiation band cannot be accurately reflected in the prior art. Comprising the following steps: firstly, dividing a space into three-dimensional grids; secondly, establishing a local coordinate system; then, high-energy particles with different angles and different energies are put into the grid points, and the motion state of the high-energy particles is tracked; then, counting particle distribution states at different time intervals, and generating a particle distribution image; establishing a function of relaxation time of the high-energy particles by comparing particle images at different times; and finally, calculating relaxation time under different space weather conditions, and establishing a database containing the function relationship between the input parameters and the relaxation time. The spatial range of the method can obviously cross a radiation band and a near-earth space, and the calculated relaxation time can provide necessary technical support for communication, navigation and the like.

The invention discloses a nuclear magnetic signal separation method for water in a miscible solution in a porous medium, and relates to the technical field of fluid flow research, and the method comprises the following steps: S1, selecting a porous medium core sample to be detected, and obtaining the gas logging porosity and permeability of the core; s2, injecting ethanol into the saturated water rock core to simulate a displacement process, and obtaining relaxation time distribution of the rock core; s3, injecting ethanol into the dried rock core, and obtaining relaxation time distribution of the rock core; s4, heavy water is injected into the saturated water rock core, and relaxation time distribution of the rock core is obtained; s5, obtaining relaxation time distribution of water in a mixed solution of ethanol and water; s6, acquiring an ethanol injection PV critical value of a differential spectrum method; s7, obtaining an ethanol injection PV critical value of a time domain analysis method; and S8, selecting a differential spectrum method or a time-domain analysis method to separate a nuclear magnetic signal of water in a mixed solution of ethanol and water in the porous medium. The problem that the content and distribution change of water in the porous medium in the miscible-phase displacement process are difficult to accurately measure by an existing conventional displacement experiment method is solved.

A NMR tool for use in a wellbore in a subterranean region includes a magnet assembly to produce a magnetic field in a volume in the subterranean region; an antenna to produce an excitation in the volume, and to receive a plurality of spin echo waveforms from the volume; and a computing system coupled to the antenna and configured to: apply a first acquisition window having a first duration to the spin echo waveforms to generate a corresponding first echo train including a first plurality of NMR echo signal amplitudes; apply a second acquisition window having a second duration different than the first duration, to at least some of the spin echo waveforms to generate a corresponding second echo train including a second plurality of NMR echo signal amplitudes; and determine a relaxation parameter based on a single inversion of the first and second echo trains.

The embodiment of the invention provides a tight reservoir nuclear magnetic resonance T2 spectrum correction method and device, and is applied to the technical field of oil-gas exploration and development. Acquiring an internal magnetic field gradient of the rock sample; measuring a standard tight reservoir nuclear magnetic resonance T2 spectrum of the rock sample under a short echo interval condition and a to-be-corrected tight reservoir nuclear magnetic resonance T2 spectrum under a long echo interval condition, wherein the standard tight reservoir nuclear magnetic resonance T2 spectrum is used for constructing an interval porosity-amplitude relation model; and correcting the to-be-corrected tight reservoir nuclear magnetic resonance T2 spectrum based on the internal magnetic field gradient, a preset interval porosity-amplitude relation model and a preset T2 cut-off value to obtain a corrected tight reservoir nuclear magnetic resonance T2 spectrum. In this way, the influence of the internal magnetic field gradient and the influence of short relaxation signal loss under the long echo interval can be reduced at the same time, so that reservoir parameters and pore structures can be accurately evaluated.

The invention discloses a method for non-destructively identifying the gender of a transformed young duck egg based on a singing tube nuclear magnetic image, and belongs to the technical field of poultry egg detection.The method comprises the steps that a low-field nuclear magnetic resonance technology is utilized, a breeding duck egg is positioned in a nuclear magnetic system, the optimal imaging section of a singing tube is determined, an image is collected and preprocessed, and a high-quality singing tube nuclear magnetic image is obtained; and through analyzing relaxation characteristics, inverting nuclear magnetic signals to identify a buzzer tube structure and extracting characteristics, finally constructing a gender decision-making model, and combining physical constraints to obtain a gender discrimination result as a sorting reference. According to the method, lossless, early-stage and high-accuracy sex identification is realized through a special imaging technology and algorithm by utilizing sex difference nuclear magnetic characteristics of a singing tube structure, hatching and breeding strategies can be optimized in laying duck and meat duck breeding, and intelligent development of the industry is promoted.

The present invention comprises a method for jointly processing data from the nuclear magnetic resonant (NMR) response of oil and rock samples in in natura condition, and its main product is the delimitation of the oil saturation (So) present in the rock samples, i.e., the determination of the range of admissible values of the volumetric fraction of the porous volume of the rock occupied by such fluid. The method requires a small volume of oil, originating from or of a composition similar to the oil present in the rock being tested, since it is based on both the measurement of the NMR response of the rock sample and the response of the fluid sample. These two sets of data feed a statistical inference scheme that (1) determines a range of admissible values for the So of the sample, delimited by the minimum and maximum oil saturation values compatible with the two sets of data presented; (2) produces, for each of these extreme values of admissible So, a decomposition of the rock relaxation time spectrum into two complementary spectra, the first highlighting the signatures relating to oil and the second comprising the distribution of the rock relaxometric signatures that cannot correspond to such fluid under the prescribed saturation condition.

The invention discloses a method for rapidly measuring the surface wettability of ore grains based on low-field nuclear magnetic resonance, and belongs to the technical field of wettability measurement. According to the method, contact angles of part of energy, metal and non-metal ore particles are respectively tested through a seat drop method, then a T2 relaxation spectrum is obtained through a low-field nuclear magnetic resonance test, then a T2 weighted average value T2g value at different wetting times is obtained, linear quantitative fitting is carried out on the T2g value at different wetting times and the wetting time, and the wetting time is calculated. Obtaining a slope value kT2g of the linear function; performing first-order linear fitting on the kT2g and a corresponding ore grain contact angle theta to obtain a relational expression between the kT2g and the contact angle theta, and obtaining the wettability of the to-be-measured wettability ore grains through the relational expression between the kT2g and the contact angle theta. The linear model between the slope value and the contact angle of the T2 weighted average and wetting time fitting function established by the method is accurate and reliable, the evaluation of the surface wettability of the ore grains can be completed in only 3 minutes, and the method has the advantages of rapidness, high efficiency and the like.

The invention discloses a particle energy spectrum inversion method and a particle energy spectrum inversion system based on double regular coefficients, so as to achieve the purpose of one-time inversion of electron and proton energy spectrums by using fewer detection devices. The detector is a single detector and detects electrons and protons at the same time, and the method comprises the following steps: generating a first inversion model based on the detector; wherein the first inversion model comprises a local relaxation coefficient and a biregular coefficient, and the biregular coefficient comprises a first regularization coefficient corresponding to electrons and a second regularization coefficient corresponding to protons; presetting a local relaxation coefficient set of local relaxation coefficients and a biregular coefficient set of biregular coefficients, performing iterative calculation on the first inversion model by adopting a Boosted-Gold algorithm based on the biregular coefficients on the basis of the local relaxation coefficient set and the biregular coefficient set, and recording an energy spectrum norm and a residual norm which meet a preset convergence condition; and generating an L curve based on the spectral norm and the residual norm, and taking an inflection point of the L curve as an optimal solution for inversion.

The invention belongs to the field of biomedical imaging, particularly relates to a multicolor magnetic particle imaging method and system based on magnetic field free line projection decoding, and aims to solve the problems of low imaging efficiency and quality caused by the absence of a relaxation-based multicolor imaging method by using a magnetic field free line in the prior art. The method comprises the following steps: respectively placing N kinds of magnetic nanoparticles in an imaging view center for scanning, and obtaining a time-frequency spectrum center spectral line by adopting time-frequency analysis; scanning an imaging object, acquiring a voltage response signal and performing time-frequency analysis to obtain a time-frequency spectrum; a linear equation set is constructed and solved, and all unknown quantities are obtained; discretely rotating the free line of the magnetic field by P angles, and obtaining the content distribution of N magnetic nanoparticles at each angle; and constructing a sinogram of the N magnetic nanoparticles, performing back projection reconstruction to obtain multicolor images, and superposing the multicolor images to obtain a reconstructed image. According to the invention, relaxation-based multicolor imaging is realized by using the free line of the magnetic field, and the imaging efficiency and quality are improved.

The invention provides a relaxation exchange magnetic resonance imaging REXI sequence. A filtering module is composed of a 90-degree excitation radio frequency pulse and a 180-degree refocusing radio frequency pulse; the switching module is composed of a 90-degree excitation radio frequency pulse and switching delay; the detection module is composed of a 90-degree excitation radio frequency pulse and a plurality of 180-degree refocusing radio frequency pulses; paired crushing gradient pulses are applied to the filtering module and the detection module; and applying a phase-disturbing gradient pulse to the switching module. The invention further discloses an acquisition and analysis method of the REXI sequence, in REXI acquisition, the echo time of the filter module is fixed, and only the exchange delay time of the exchange module and the echo time of the detection module are changed; and performing REXI analysis, and fitting data by adopting a double-chamber exchange model. The invention also discloses an application of the REXI sequence and the acquisition and analysis method thereof in magnetic resonance imaging measurement of cerebrospinal fluid transmembrane transport, and the REXI sequence is especially suitable for magnetic resonance imaging for rapidly measuring the molecular exchange speed between a short T2 component and a long T2 component in a two-component system.

The invention relates to a method and a system for evaluating shale pore connectivity based on a nuclear magnetic resonance pulse sequence. The method comprises the following steps: editing and measuring gradient magnetic field distribution in shale based on a stimulated echo pulse sequence; measuring shale two-dimensional transverse relaxation time-transverse relaxation time distribution based on the T2 exchange experiment pulse sequence; according to the internal gradient magnetic field distribution of the shale and the two-dimensional transverse relaxation time-transverse relaxation time distribution of the shale, the exchange rate of the fluid among different apertures is analyzed; and evaluating the shale pore connectivity according to the exchange rate. The system comprises a first measurement module, a second measurement module, an analysis module and an evaluation module. According to the method, the influence of transverse relaxation time in the gradient editing process is reduced, and the interference of relaxation attenuation on signals in micro pores is reduced; a gradient magnetic field in a measurement sample is edited by using a stimulated echo pulse sequence, and the influence of nuclides of other types on sample measurement and analysis is small.

The invention belongs to the technical field of oil and gas reservoir engineering and multiphase seepage dynamic monitoring, relates to a characterization method of seepage behaviors of multiphase fluid in a porous medium, and particularly provides a dynamic construction method of a multiphase displacement capillary pressure-saturation relationship based on nuclear magnetic resonance. Comprising the following steps: S1, acquiring a low-field nuclear magnetic resonance relaxation spectrum of a porous medium in a gas-water two-phase displacement process; s2, determining two-phase fluid interfacial tension, a wetting contact angle and a rock surface relaxation rate; s3, determining the dynamic cut-off relaxation time of the displacement stage; s4, calculating equivalent capillary pressure; the residual water saturation is calculated, and the equivalent capillary pressure is the capillary pressure corresponding to the current displacement stage and is used for constructing a capillary pressure-saturation curve. According to the method, the capillary pressure change in the porous medium can be obtained only through spectral analysis without a centrifugal or mercury injection experiment.

The invention discloses a decoupling method based on high-field solid-state nuclear magnetic resonance T2 relaxation, and the method comprises the steps: carrying out the preprocessing of a collected T2 relaxation signal, including data conversion, chemical shift sorting, normalization processing and signal screening; converting the time domain signal into a frequency domain model by adopting inverse Laplacian transformation, and extracting pole features; on the basis of frequency domain pole information, automatic estimation and nonlinear fitting of signal parameters are achieved through radial basis function fitting in combination with a numerical optimization algorithm; and storing the processed time domain signal data. The method innovatively solves the technical problem of multi-atomic-nucleus relaxation signal analysis under the high-field condition, has the advantages of high signal-to-noise ratio, good analysis precision, wide application range and the like compared with a traditional low-field nuclear magnetic technology, and is particularly suitable for research and analysis in the fields of energy materials, catalysts and the like. And the processing capability and the decoupling effect of the high-field solid-state nuclear magnetic resonance relaxation signal are remarkably improved through technologies of system integration signal conversion, parameter optimization, regularization processing and the like.

The invention discloses a low-field nuclear magnetic resonance exploration device and method capable of effectively shortening dead zone time, and relates to the field of electric signal acquisition, and the device comprises an upper computer which is used for communicating with a main control circuit; the main control circuit is used for controlling and collecting the core and comprehensively controlling the work of the device; the power amplification circuit is used for amplifying the power signal input by the main control circuit and then transmitting an alternating current pulse to excite the coil; the beneficial effects of the invention are that the coil employs a transmit-receive integrated differential structure, which inhibits common-mode noise interference and improves the signal-to-noise ratio of detection; the Q-conversion circuit reduces the quality factor of the coil through parallel connection of energy discharge resistors at the two ends of the coil, the purpose of rapidly discharging energy stored in the coil is achieved, and the dead time can be effectively shortened; the high-isolation fast-switching radio frequency switch can effectively reduce the insertion loss and the generated noise, significantly reduce the switching time, further shorten the dead zone time, and improve the detection effect of a short relaxation target body.

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 invention belongs to the technical field of cerium-based rare earth oxide dispersibility testing, and particularly relates to a method for evaluating cerium-based rare earth oxide particle surface characteristics and slurry dispersion stability. Comprising the following steps: when cerium-based rare earth oxide particles are synthesized, adding a paramagnetic element as a probe, and mixing the synthesized particles with a dispersing agent and water to obtain mixed slurry; nuclear magnetic resonance scanning is adopted, the body water relaxation peak and the particle surface bound water and body water exchange dynamic relaxation peak of the mixed slurry in each stage of the process from uniform mixing to standing layering are measured, and the particle surface characteristics are evaluated based on the relaxation efficiency; meanwhile, a linear relation between the relaxation peak area proportion and the sedimentation time in the standing layering process is constructed, a fitting slope value is obtained, and the dispersion stability of the mixed slurry is evaluated. According to the method, non-intrusive in-situ detection of the dispersion stability of the cerium-based rare earth oxide particle slurry is realized by innovatively using a low-field nuclear magnetic resonance mode, and accurate comparison and evaluation of the dispersion stability can be realized.