33 results about "T2 value" patented technology

The invention relates to a method for determining T2cutoff value by nuclear magnetic resonance logging (NMRL) T2 spectra, comprising the steps of: 1. classifying NMRL T2 spectra by shape characteristics; 2. fitting and obtaining centrifugal spectrum according to different types of logging T2 spectra; 3. making area integration on the centrifugal spectrum and obtaining area of centrifugal spectrum; 4. calculating areas of logging T2 spectra; 5. accumulating the areas of logging T2 spectra, and as the accumulated area is equal to or closest to the area of centrifugal spectrum, the corresponding T2 value is a T2cutoff value. Thus, the invention determines T2cutoff value of each depth point by directly using NMRL T2 spectra.

The embodiment of the invention discloses a method and a system for determining a transformation relationship between a tight sandstone aperture and a nuclear magnetic resonance T2 value, and relatesto the technical field of oil and gas reservoir stratum geological evaluation. The method comprises the following steps that: carrying out CT (Computed Tomography) on an obtained tight sandstone sample to obtain a three-dimensional digital core; through the three-dimensional digital core, obtaining aperture radius and volume data, and further obtaining a digital core aperture radius distribution diagram; carrying out saturated salt water nuclear magnetic resonance measurement on the tight sandstone sample to obtain a nuclear magnetic resonance T2 spectrogram; and on the basis of the digital core aperture radius distribution diagram and the nuclear magnetic resonance T2 spectrogram, according to an equal porosity principle, establishing a crossplot of the aperture radius rc and the nuclearmagnetic resonance T2 spectrogram, and carrying out fitting to obtain a relational expression of rc and T2. By use of the embodiment of the invention, the quantitative calculation of the transformation relationship between the tight sandstone aperture radius and the nuclear magnetic resonance T2 value is realized. Compared with the transformation relationship obtained through mercury penetration pore throat distribution and the nuclear magnetic resonance T2 spectrogram in the prior art, the transformation relationship obtained by the method is more reliable, and therefore, the tight sandstonereservoir stratum full-scale aperture structure is further accurately represented.

A method of investigating an object using nuclear magnetic resonance (NMR) equipment includes generating a one-dimensional projection of the object for each of a plurality of echoes utilizing echo train signal indications resulting from pulse sequences, and utilizing the plurality of one-dimensional projections, for each of the plurality of echoes, generating NMR image data for at least one location in the object. The NMR image data may be displayed. The displayed data may include a T2 decay curve, a T2 value display, a T2 distribution graph, or petrophysical data for at least one object location.

The time extreme method of measuring the transmitting speed of ultrasonic wave in bone belongs to the field of measurement technology, and solves the technological problem of providing a simplified method for measuring the sound transmission speed of sound in bone. The technological scheme includes setting ultrasonic emitter A1 and ultrasonic receivers B1 and B2 arranged in a probe casing to cover the outer surface of the soft tissue outside one section of bone; connecting the ultrasonic emitter and ultrasonic receivers to the signal processing unit in the ultrasonic instrument; emitting ultrasonic wave to the bone with the ultrasonic emitter and receiving ultrasonic waves T1 and T2 with the ultrasonic receivers; shifting the measurement probe slightly and processing the measured T1 and T2 values to obtain maximum T1 value and calculating the ultrasonic wave velocity on the surface of bone based on the formula VB=L/(T2-T1).

The invention relates to a method for obtaining contrast agent relaxation time. The method comprises the following steps: automatically identifying a contrast agent sample in an image, precisely positioning a sample center point, and calculating the radius of a sample test tube, automatically selecting ROI (Region of Interest) by the center point of the test tube as the center according to the radius of the test tube, calculating the mean value of a pixel signal in the ROI, and experimenting a standard deviation; and finally, carrying out nonlinear fitting to an automatically-extracted signal, and accurately, quickly and efficiently calculating a spinning-lattice relaxation time T1 value and a spinning-lattice relaxation time T2 value of the contrast agent. A process that a plurality of samples are identified in the image and the ROI of the samples is selected is a computer automation process, an artificial process is omitted, and the positioning accuracy, the ROI shape consistency and the result accuracy of the invention are far better than those of a traditional method. The whole flow from ROI selection and ROI signal extraction to the nonlinear fitting is a fully-automatic process, and the time efficiency of the method is far higher than the time efficiency of the traditional method.

The invention relates to the technical field of nuclear magnetic resonance imaging, and discloses a correction measurement method and device for a transverse magnetization vector decay time constant,computer equipment and a non-uniform field magnetic resonance system. In an extremely non-uniform magnetic field or a nuclear magnetic resonance system which cannot realize extremely short echo time,an ADC-T2 two-dimensional atlas is fitted firstly through the acquired echo signals acquired by applying the SE-CPMG sequences with different b values, and then a transverse magnetization vector decaytime constant T2 is corrected so that the problem of a small T2 measurement value caused by diffusion can be avoided. Besides, an accurate ADC-T2 two-dimensional atlas can be further obtained based on the corrected T2 measurement value, T2 value measurement is ensured not to be affected by echo time and molecular diffusion, the requirement for the system is low, and system cost can be reduced.

Process control system for detecting abnormal events in a process having one or more independent variables and one or more dependent variables. The system includes a device for measuring values of the one or more independent and dependent variables, a process controller having a predictive model for calculating predicted values of the one or more dependent variables from the measured values of the one or more independent variables, a calculator for calculating residual values for the one or more dependent variables from the difference between the predicted and measured values of the one or more dependent variables, and an analyzer for performing a principal component analysis on the residual values. The process controller is a multivariable predictive control means and the principal component analysis results in the output of one or more scores values, T2 values and Q values.

The invention provides a multi-parameter quantitative test system and method for tissue attributes. The system comprises: a scanning module used for scanning a subject based on a preset sequence, wherein the preset sequence comprises a flip recovery preparation IR pulse, a T2 preparation pulse and a series of excitation pulses; an acquisition module used for acquiring single-gradient echo data and multi-gradient echo data in a scanning process, wherein the single-gradient echo data and the multi-gradient echo data comprise sampling spokes; a reconstruction module used for performing reconstruction based on sampling spokes corresponding to different T2 preparation pulses T2prep and different flip moments TI in the single-gradient echo data to obtain a plurality of first weighted images including T2 and T1, and performing reconstruction based on sampling spokes corresponding to different acquisition moments TE in the multi-gradient echo data to obtain a plurality of second weighted images of T2*; and a fitting module used for fitting based on the first weighted image to obtain a T2 value and a T1 value of the tissue, and fitting based on the second weighted image to obtain a T2* value of the tissue.

The invention discloses a cartilage injury degree assessment method based on multimodality magnetic resonance. The cartilage injury degree assessment method comprises the steps of S1, preparing 15 healthy adult small rams; S2, respectively constructing moulds on 3 groups of the rams; S3, imaging the multimodality magnetic resonance cartilage; S4, recording number; S5, performing tissue analysis; and S6, performing data analysis. Through the three groups namely A, B and C of the rams, the fluctuating change of T2 value of the rams at the 0th week, the 3rd week, the 6th week and the 9th week andthe content of glycosaminoglycan in the articular cartilage (GAG), the correlation analysis is performed on the content of collagen, so that the obtained T2 mapping technique is used for expressing the accuracy of the cartilage injury.

The invention provides a coalbed gas content analysis method based on a nuclear magnetic resonance T2 spectrum. The method comprises the steps that 1) nuclear magnetic resonance rock physics testing is carried out on a full-diameter coal rock sample of an unconventional formation to acquire the T2 spectrum of the sample; 2) a movable fluid peak and a bound fluid peak are determined based on the T2spectrum of the sample; 3) the relationship between the ratio of the area enclosed by the bound fluid peak to the area enclosed by the movable fluid peak and the percentage of a movable fluid is established; and 4) the relationship between the percentage of the movable fluid and the gas content of a reservoir is established by comparing the T2 spectrum of different samples with the measured gas content of the reservoir. According to the invention, the unique double-pore structure characteristics of a coalbed gas reservoir is disclosed through the distribution analysis of the full-diameter coal core nuclear magnetic resonance T2 value of the unconventional coal rock formation, and key factors determining the gas content of coal rock are proposed. The method provided by the invention provides a basis for a logging formation interpretation method, and has obvious social and economic benefits.

A method for evaluating effects of pores with different dimensions on the compressibility of a total pore during pressurization comprises the following steps: configuring experimental simulated formation water; placing a core in a magnetic resonance imaging high-temperature high-pressure displacement system, and measuring magnetic resonance imaging T2 spectrums; drawing the magnetic resonance imaging T2 spectrums under different confining pressures on a same graph; according to magnetic resonance imaging T2 values, dividing the magnetic resonance imaging T2 spectrums into two parts, i.e., a part representing large pores, and a part representing small pores; respectively carrying out statistics on areas surrounded by the T2 spectrums of the large pores under the different confining pressures and the X axis, and areas surrounded by the T2 spectrums of the small pores under the different confining pressures and the X axis; and calculating compressibility coefficients of a total pore, the large pores and the small pores under the different confining pressures, calculating the sum of differences between the compressibility coefficients of the large pores and the compressibility coefficients of the total pore under the different confining pressures and the sum of differences between the compressibility coefficients of the small pores and the compressibility coefficients of the total pore under the different confining pressures, and determining effect degrees of the large pores and the small pores on the compressibility of the total pore. The method provided by the invention has the advantages that pore space changes are essentially reflected, the pore volume compressibility is used as a quantitative evaluation indicator, and the mechanism of pore changes under the pressures in a stress-sensitive process is disclosed.

The invention discloses a method and system for optimizing nuclear magnetic resonance logging reservoir parameters, a storage medium and electronic equipment. The method comprises the following steps that T2 values at different time points of nuclear magnetic resonance logging and corresponding amplitude values are obtained, and a T2 spectrum is obtained; obtaining a T2 cutoff value meeting a preset condition by searching the T2 spectrum; based on each T2 value and the T2 cut-off value, obtaining denoising coefficient distribution through calculation; and obtaining a denoised T2 spectrum through a second calculation formula based on each T2 value and the denoising coefficient distribution. According to the method, the porosity, the movable fluid volume and the permeability are calculated through the accurately denoised T2 spectrum, the accuracy and effectiveness of reservoir parameter evaluation are improved, and drilling of a detection oil well is facilitated.