13 results about "Transverse isotropy" patented technology

A method is described for generating high-resolution images of transversely isotropic mechanical properties and attenuation properties of tissues associated with measured compressional waves. A pressure wave is transmitted to a region containing fibers that are oriented with transverse isotropy. Waves are received that propagate after the pressure wave has impinged upon the fibers. An initial velocity and attenuation model is created that takes into account the transverse isotropy of the fibers. Full Waveform Inversion (FWI) is used to iteratively minimize a difference between the received data and the initial velocity and attenuation model to create an image of the region that takes into account the transverse isotropy of the fibers. The image has a higher resolution than if created using the initial velocity and attenuation model.

Systems and methods for using cross-well seismic data to image reservoir structures illuminated with sources located in a lateral well and receivers located in one or more nearby lateral wells. The systems and methods include numerical FWI algorithms and workflows based on an elastic vertical transverse isotropy (VTI) anisotropic full waveform inversion (EFWI) engine. The EFWI engine is used for inversions based on the cross-well seismic data and additional data (e.g., well logs, vertical seism profiles). Inversion results include 2D / 3D maps of elastic properties (e.g., velocity, anisotropy, density, attenuation) of subsurface. The EFWI engine includes a wave propagation modeling accounting for various seismic waves propagating in the subsurface.

A method that includes disposing an acoustic logging tool in a borehole. The acoustic logging tool comprises one or more transmitters and one or more receivers. The method may further comprise taking one or more acquisitions with the acoustic logging tool as the acoustic logging tool traverses through the borehole, creating an azimuth rotation angle array of one or more angles, from the one or more acquisitions, and applying a trial angle selected from the one or more angles of the azimuth rotation angle array to calculate a fast shear waveform.

The invention discloses a seismic four-parameter linear direct inversion method based on a transverse isotropic medium reflection coefficient precision formula, and belongs to the technical field of unconventional reservoir seismic exploration. According to the method, an accurate Graebner reflection coefficient equation is deduced again, four pseudo-stiffness coefficients are introduced to re-characterize the reflection coefficient, and the number of to-be-inverted parameters is reduced from 5 to 4, so that the discomfort of an inverse problem is reduced. In order to improve the calculation efficiency of inversion, the partial derivative of the positive operator after the density item is eliminated is deduced to realize linear inversion of four parameters. In order to improve the precision of anisotropy parameter estimation, an indirect inversion strategy is adopted, four pseudo-stiffness coefficients are obtained through inversion, and then the anisotropy parameters epsilon and delta are estimated through inversion results. The feasibility of the inversion method is verified through a synthetic data test.

The invention provides a multi-wave joint inversion method and device, electronic equipment and a storage medium. The multi-wave joint inversion method comprises the steps of determining a longitudinal wave-longitudinal wave angle gather and a longitudinal wave-transverse wave angle gather in a longitudinal wave-longitudinal wave angle gather time domain in seismic data; determining formation parameters of a wellhead of the receiving well, and determining an initial inversion model according to the formation parameters of the wellhead; according to the initial inversion model, determining a longitudinal wave-longitudinal wave synthesis record and a longitudinal wave-transverse wave synthesis record by using an accurate vertical transverse isotropic medium reflection coefficient equation; determining a real stratum model, determining relationships between the longitudinal wave-longitudinal wave synthesis record and the longitudinal wave-longitudinal wave angle gather and between the longitudinal wave-transverse wave synthesis record and the longitudinal wave-transverse wave angle gather by using a Bayesian framework, and determining an optimal model of the real stratum model by using a maximum posterior probability; and linearizing the accurate vertical and transverse isotropic medium reflection coefficient equation by using a Gaussian Newton method, determining the update quantity of the initial inversion model, and updating the initial inversion model by using the update quantity.

This application provides a method, device, and storage medium for predicting fracture density based on azimuth anisotropy, belonging to the field of geophysical research technology. The method includes: substituting fracture-related test data into a prediction formula to calculate the P-wave reflection coefficient. The prediction formula is an approximate formula for the P-wave reflection coefficient of a transversely isotropic medium, and the right-hand side variable of the prediction formula includes at least the fracture density in different directions; extracting well-side seismic trace data from azimuth-based stacked traces and deconvolving it to obtain a seismic wavelet; calculating the P-wave reflection coefficient data volume of the target work area based on the seismic wavelet and azimuth-based stacked traces; and inverting the fracture density in different directions of the target work area using an interpolated initial model as a constraint. The above method is based on an improved prediction formula, whose right-hand side variable includes the fracture density in different directions, realizing direct inversion of fracture density, reducing inversion time and accumulated errors, and improving the efficiency and accuracy of fracture density prediction.

The invention discloses a DAS data image generation method and device for underground structure visualization. Comprising the following steps: constructing a three-dimensional coordinate system, and obtaining an original sound wave equation, a strain rate parameter and a seismic source parameter of a vertical and transverse isotropic medium; simplifying the strain-displacement relational expression to obtain a conversion relation between the axial strain rate and the velocity component; speed components in the original acoustic wave equation are replaced based on the conversion relation, and an anisotropic acoustic wave equation suitable for DAS data is constructed; deducing a seismic source wave field extrapolation equation and a detection point wave field extrapolation equation according to the anisotropic acoustic wave equation; respectively inputting the focus parameter and the strain rate parameter into corresponding extrapolation equations to obtain a focus pressure wave field and a detection point pressure wave field; and performing mutual-closing imaging processing on the two types of pressure wave fields to obtain an initial result, and performing optimization processing to obtain an underground structure imaging result of the target DAS data. According to the invention, the precision and reliability of DAS data underground structure imaging under complex geological conditions are improved.

Methods and systems for determining in-situ stresses in anisotropic rocks are presented. The methods consider both anisotropic rock properties, geothermal and tectonic effects. They calculates in-situ stresses for subsurface rocks with anisotropies and non-isothermal effects, so that they can be applied to geothermal energy and geo-energy. Horizontal stresses in the vertical transverse isotropy (VTI) rock and in the horizontal transverse isotropy (HTI) rock are obtained for calculating in-situ stresses in naturally fractured rocks. Compared with the conventional isotropic model, the method applicable to VTI rocks predicts a higher minimum horizontal stress and a higher maximum horizontal stress, which is suitable for shales and other laminated formations. The method applicable to HTI rocks gives a lower minimum horizontal stress than the conventional model. Geothermal temperature effects are also integrated into the methods so that the methods are applied to geothermal energy.

A method that includes disposing an acoustic logging tool in a borehole. The acoustic logging tool comprises one or more transmitters and one or more receivers. The method may further comprise taking one or more acquisitions with the acoustic logging tool as the acoustic logging tool traverses through the borehole, creating an azimuth rotation angle array of one or more angles, from the one or more acquisitions, and applying a trial angle selected from the one or more angles of the azimuth rotation angle array to calculate a fast shear waveform.

The present application relates to the technical field of oil exploration, and more particularly to a method and system for modeling earth stress based on transverse isotropy; comprising the following steps: S1, obtaining well logging data of a study area well, processing and correcting missing sections of the well logging data to obtain processed well logging data; S2, calculating formation pore pressure based on the processed well logging data obtained in step S1; S3, calculating elastic parameters of a transversely isotropic medium, the elastic parameters including Young's modulus and Poisson's ratio; S4, establishing an earth stress model according to the formation pore pressure obtained in step S2 and the elastic parameters obtained in step S3; the present application is suitable for high-precision earth stress calculation of super-deep drilling complex lithology.

The application relates to the field of building structure engineering and discloses a deflection calculation method for a web-opening steel-timber composite beam, which comprises the following steps: determining the geometric parameters, material parameters and opening size of the steel-timber composite beam; measuring the mechanical property parameters of steel and bamboo plywood, and calculating the overall bending stiffness of the composite beam; respectively calculating the overall deflection without openings and the local deflection under the influence of openings according to loading conditions; superimposing the deflection without openings and the deflection with openings to obtain the overall deflection distribution of the composite beam; and determining the maximum deflection value and the position of the composite beam. Through the establishment of the superposition model of the deflection of the non-opening and opening areas, the transverse isotropic characteristics of the bamboo, the steel stiffness and the secondary bending moment distribution of the opening area are comprehensively considered, the influence of the openings on the overall deflection can be accurately calculated, the opening arrangement design is optimized, and a theoretical basis is provided for the structure design and checking of the steel-timber composite beam.

The application discloses a Neper-DEM-based modeling and calculation method of phanerocrystalline rocks with bedding structure, relates to the numerical calculation field of tunnel engineering technology, and solves the problem that the prior art lacks a simulation and calculation method of phanerocrystalline rocks such as gneiss and granulitic gneiss with transverse isotropy; the application comprises the following steps: constructing a polycrystal structure with crystal characteristics in Neper, and then generating the polycrystal structure into a geometric parameter text of a crystal grain; constructing a discrete element rock sample model in DEM; performing numerical simulation test on the discrete element rock sample model to obtain a stress-strain curve and a sample failure mode, wherein the numerical simulation is realized by adopting a Brazilian split test and a triaxial test; calibrating discrete element sample calculation parameters according to the numerical simulation result, and verifying the effectiveness of the modeling and calculation method of the discrete element rock sample model; and the application realizes the construction and assignment of the crystal structure and the bedding structure at the same time in the modeling method, so that the rock structure is closer to the real rock structure.

The invention discloses an improved friction pile torsional vibration analysis method and system, a storage medium and application of the improved friction pile torsional vibration analysis method and system, relates to pile foundation engineering dynamic analysis, and mainly solves the key but often neglected influence factor of a sediment layer with limited thickness between a pile end and bedrock. By introducing a virtual unsaturated soil pile method, a pile body virtually extends to a bedrock surface, and the FUSP maintains the fractional order viscoelasticity characteristic of surrounding soil. The soil body control equation integrates viscoelasticity characteristics of three-phase interaction, transverse isotropy and fractional calculus, and unified modeling of the friction pile and the end bearing pile is achieved. An analytic solution of frequency domain torsional impedance is deduced through a variable separation method and an eigenfunction expansion method, and a semi-analytic time domain response under semi-sine pulse excitation is obtained in combination with inverse Fourier transform and a convolution theory. The method can provide a high-precision theoretical analysis tool for aseismic design and dynamic response prediction of the friction pile foundation in the unsaturated land area.