72 results about "Velocity inversion" patented technology

The invention provides a method for tomography velocity inversion based on angle domain common imaging gathers under a complicated condition. The method comprises the following steps of: by using a velocity model obtained by common velocity analysis as an initial velocity model, extracting the angle domain common imaging gathers based on a double-square-root continuation pre-stack depth migration method; picking a rest depth difference on the extracted angle domain common imaging gathers, and calculating a travel residual; picking a horizon interface on a migration section surface, building a reference velocity model needed by the ray-tracing forward, calculating a sensitivity matrix by using an undulating surface ray tracing method; creating an inversion equation set to which a regularization factor is added by using the travel residual and the sensitivity matrix; solving the equation set by using an LSQR (Least-squares QR decomposition algorithm) and updating the velocity model; and extracting the angle domain common imaging gathers by using the updated velocity model based on the double-square-root continuation pre-stack depth migration method.

The invention discloses a full waveform joint inversion method for improving high steep structure velocity inversion efficiency, and belongs to the petroleum geophysical exploration field. The method comprises the steps: establishing an observation system by inputting the initial velocity field, the shot record and the focus wavelet; utilizing traditional reverse time migration to obtain the imaging result which is taken as a reflection coefficient model, and applying linear forward modeling and linear wave field back propagation; calculating the gradient directions of two prism waveforms and adding the gradient directions together to calculate the inverse gradient direction of the prism waveform, using the linear search method or a parabolic fitting method to calculate the updated step, and using the calculated gradient direction and step to update the velocity; using the conventional full waveform inversion method to update the velocity again, and determining whether or not to satisfy the error condition; if not, using the updated velocity as the input velocity, and updating the velocity again; and if so, outputting the inversion result. The full waveform joint inversion method for improving high steep structure velocity inversion efficiency reduces the dependency about whether the high steep structure information is missing in the initial model, and improves the inversion accuracy and efficiency for the high steep structure.

The invention discloses an oil shale earthquake identification and evaluation method, which comprises the steps: a) calculating shale gas organic carbon content TOC through a wave impedance delta logR superposition method; b) the TOC value calculated in the step a) being same with the actually-measured TOC value of samples; c) establishing a rock physical model of an oil shale; and d) establishing a logging curve of logging information and seismic attribute longitudinal wave velocity by utilizing seismic channels beside a shale gas well. The rock physical model is established, and organic content of the oil shale is obtained through velocity inversion; and through the earthquake multi-attribute prediction technique, oil content information is inverted and extrapolated to seismic data, so that earthquake oil content inversion data volume of a work area is obtained, and a foundation is laid for identification and evaluation of the oil shale.

The invention relates to a submarine sound velocity passive access method based on a noise field vertical vibration velocity signal. The method comprises the steps that a marine environment noise field vector signal vertical coherent characteristic prediction model is built, aiming at three elements of inversion, an optimization algorithm, forward modeling and a cost function, a submarine sound velocity inversion model based on noise field vertical vibration velocity signal vertical coherent characteristics is given, and noise field vertical coherent characteristics are selected for conductinginversion of the submarine sound velocity. Accordingly, seawater acoustic parameters can be obtained through actual measurement, by means of a submarine geological database, geology types of the experimental seafloor can be obtained roughly, the search range of submarine parameters can be determined through table look-up, by means of a genetic algorithm, the best agreement of noise field verticalcoherent characteristic results and measured results under a group of ground acoustic parameters, and the parameters can be approximatively considered as actual submarine earth sound parameters.

The invention relates to a P-wave and S-wave combined static correction method based on surface S-wave velocity inversion. Through high-precision wave field interpolation, by jointly using P-wave and converted wave data and surface wave information, and through weighted superposition, the accuracy of direct S-wave velocity inversion is effectively improved, the problem that static correction is inaccurate for a conventional method in which the amount of S-wave static correction is solved indirectly is effectively solved, and the imaging level of multi-wave data is effectively improved. Through application test in three-component seismic data processing of the Luojia area of the Shengli oil field, a good processing effect is achieved, which proves that the P-wave and S-wave combined static correction method based on surface S-wave velocity inversion is feasible.

The invention provides a fracture developing predicting method and device, and relates to the technical field of petroleum geophysical prospecting. According to the invention, a longitudinal wave velocity azimuthal anisotropy feature based on pre-stack wide azimuth seismic data is used to predict a fracture. The method comprises the steps that according to pre-set azimuth and offset range, sub azimuth and sub offset part superposition is carried out on pre-stack seismic gather data; wavelet needed by the inversion of the azimuth superposition data body of each part is determined; a low frequency model of longitudinal wave velocity, shear wave velocity and density needed by seismic inversion is determined; pre-stack elasticity parameter data corresponding to a number of partial azimuth superposition data bodies are determined; according to a least squares method, ellipse fitting is carried out on the longitudinal wave velocity inversion data and the shear wave velocity inversion data of each partial azimuth superposition data body to determine the elliptic equation parameters of the ellipse; the long axis or minor axis orientation of the ellipse is determined to characterize the fracture development direction; and the ratio of the long axis to the minor axis of the ellipse is determined to characterize the fracture density.

The invention provides a time-domain seismic interval velocity inversion method, and belongs to the field of seismic exploration data processing. The time-domain seismic interval velocity inversion method includes acquiring initial instantaneous velocities by means of seismic logging; establishing relations among the instantaneous velocities and root-mean-square velocities; converting the initial instantaneous velocities into root-mean-square velocities; constraining actually picked root-mean-square velocities to create an objective function; solving the objective function to obtain variables required for updating a velocity model; acquiring a final interval velocity when a value of the objective function is smaller than a threshold value epsilon after repeated iteration. The time-domain seismic interval velocity inversion method has the advantages that the stable velocity can be acquired by the time-domain seismic interval velocity inversion method, the stable and smooth interval velocity model can be provided for migration, the velocity can be used for seismic migration imaging, and data support can be provided for oilfield development and petroleum drilling.

The invention provides a system and a method for inversion of p-wave and s-wave velocities of elastic waves under polar coordinates, and belongs to the field of oil exploration. The method comprises the following steps of inputting initial p-wave and s-wave velocity models and multi-component seismic records; carrying out mesh generation under a polar coordinate system; converting the initial p-wave and s-wave velocity models into the polar coordinate system; computing a p-wave and s-wave gradient formula under the polar coordinate system; computing a weighted velocity step length; updating the p-wave and s-wave velocities under the polar coordinate system and judging whether an error condition is met; converting the inverted p-wave and s-wave velocities into a Cartesian coordinate system;and outputting the inverted p-wave and s-wave velocities. According to the system and the method, the velocity inversion difficulties in some special geological environments such as a borehole environment, a tunnel space and the like can be well solved; and meanwhile, a multi-component method is introduced into the system and the method, so that the p-wave and s-wave velocities can be inverted atthe same time, the more real and accurate p-wave and s-wave velocities can be obtained, and a foundation is provided for imaging and interpretation of special geological structures such as the borehole environment, the tunnel space and the like.

The invention relates to a regularized tomographic velocity inversion method and device based on a structural inclination angle. The method comprises steps that an inclination angle theta (yj, zk) of each point on an offset profile is acquired; regularized operators si (ysj, zsk) respectively taking each selected point as a center are calculated according to the inclination angles; the regularized operators si (ysj, zsk) are arranged to form a regularized matrix; the regularized matrix is acted to a tomographic inversion equation before regularization to acquire a tomographic inversion equation after regularization; the tomographic inversion equation after regularization is solved, and velocity update quantity is acquired.

The invention relates to a casing-harmonic-containing vertical seismic profile data interval velocity inversion method. The method is used for suppressing casing harmonics by low-pass filtering and F-K filtering in seismic prospection, and includes steps of obtaining amplitude spectrums by means of 15-Hz low-pass filtering, obtaining F-K spectrums by converting the amplitude spectrums in a track direction, clearing all F-K spectrums of up-going waves and down-going waves of the speed higher than 5000 m/s, obtaining a second wave field of time domain by means of inverse Fourier transform, picking a continuous event from the down-going waves of the wave field to obtain first break I of each track, picking the first break on an original interference-less track and translating the same, obtaining the first break II by adding the first break I of each track with the translation value, obtaining the adjacent difference by subtracting the depth of the previous track from the depth of the next track, obtaining the first break difference of the adjacent track by subtracting the record first break of the first track from the record first break II of the next track, and finally dividing the depth difference of the adjacent track by the first break different of the adjacent track. By the method, interference to the interval velocity from the casing harmonics can be avoided, so that accurate first break and interval velocity are acquired. Accordingly, the method is easy and convenient to use, and high in computational efficiency.

The invention discloses a speed splicing method and a speed splicing system for pre-stack depth offset. The method comprises the steps of based on seismic data, acquiring an observation travel time ofa preliminary wave, an initial speed model and a deep-layer speed model; based on the observation travel time of the preliminary wave and the initial speed model, obtaining a shallow-layer speed model through the grid tomographic inversion process; based on the shallow-layer speed model, obtaining the bottom boundary of the speed inversion; based on the deep-layer speed model, the shallow-layer speed model and the bottom boundary of the speed inversion, obtaining a depth offset speed model; performing the pre-stack depth offset based on the depth offset speed model, and obtaining a pre-stackdepth offset result. According to the invention, the shallow-layer speed model obtained through the grid tomographic inversion process and the deep-layer speed model obtained through the pre-stack time offset process are spliced, so that the high-precision pre-stack depth offset imaging is achieved.

The invention provides an imaging-domain stereo chromatography velocity inversion method. The method comprises: step one, carrying out pre-stack depth migration on an inputted initial velocity field to obtain a depth migration profile and extracting an angle-domain common imaging point set; step two, picking up a residual curvature and a depth residual of a corresponding position in the angle-domain common imaging point set, and carrying out conversion to obtain a travel time residual; step three, calculating stereo chromatography data space; step four, carrying out ray tracing in a current velocity model to obtain travel time information and an inversion kernel function in the model; and step five, establishing an inversion equation set by using the obtained stereo chromatography kernel function and residuals of real data space and data space in the model, and carrying out calculation to obtain an updating amount of the model, thereby completing the iteration. With the imaging-domainstereo chromatography velocity inversion method, the accurate stereo chromatography data space is obtained; the inversion precision and stability are improved; and the imaging-domain stereo chromatography velocity inversion method has the great utilization value in stereo chromatography inversion practice in future.

The invention discloses a detonator delay elimination method for coal mine shock wave velocity inversion and is suitable for the technical field of coal mining and coal mine safety. The method is characterized by, to begin with, marking and analyzing P-wave first arrival time of a shock wave recorded by a probe; calculating distance between each shot point and the probe; carrying out relation fitting through a linear least square method to obtain relation between the P-wave first arrival time and the distance and calculating detonator delay; and finally, eliminating the detonator delay to obtain corrected P-wave arrival time. The method can eliminate the detonator delay, so that actual propagation time of the P wave in a coal-rock mass can be calculated accurately, and accuracy and reliability of coal mine shock wave velocity inversion are improved; and the method is reliable in result, wide in application range and easy for computer programming.

The invention discloses an imaging processing method and device for an Ordovician fracture-cave system. The imaging processing method comprises the following steps of: acquiring, to be specific, acquiring a root-mean-square velocity function; converting, to be specific, converting the root-mean-square velocity function by utilizing a constraint velocity inversion method to acquire an interval velocity body; migrating, to be specific, performing prestack time migration to target seismic data to obtain migrated target seismic data; picking up, to be specific, performing automatic pickup residual velocity processing according to the migrated target seismic data to obtain a residual velocity; updating, to be specific, updating the interval velocity body according to the residual velocity body; repeatedly executing migrating, pickup processing and updating until the seismic data acquired in the migration processing step is in accordance with the requirement of geological laws so as to obtain a final interval velocity body; and performing prestack time migration processing to the whole seismic data according to the final interval velocity body. According to the imaging processing method and device for the Ordovician fracture-cave system, the imaging effect of prestack time migration can be improved, and the imaging is finer.

The invention relates to an interval velocity inversion method for earthquake waves for processing earthquake exploration data, comprising the steps of receiving the data underground and obtaining VSP (Vertical Seismic Profiling) data, picking each first arrival and integer time, calculating the first arrival difference of adjacent integer sampling points, carrying out median filter wave field separation of the VSP data and obtaining down-going waves and leveling the down-going waves; opening one time window from the first sampling point; carrying out Fourier transform on a signal to obtain the phase spectrum of each frequency; getting the phase spectrum difference of the same frequency in adjacent channels; obtaining the first arrival second difference of non-integer sampling points of the adjacent channels by least square fit; summing the first arrival first difference and the first arrival second difference to obtain the first arrival difference; and obtaining the interval velocity by dividing the depth difference of the adjacent channels by the final first arrival difference of the adjacent channels. The method has strong ability resisting to immediate (random) interference; the algorithm is simple; and the inversion interval velocity has high precision.

The present invention provides a method for improving converted-wave seismic data resolution and converted-wave seismic data high-precision velocity inversion method thereof. The wavelet transform multi-scale information is employed to obtain the frequency data amplitude spectrum requiring frequency prolongation and a curve fitting amplitude spectrum in the wavelet frequency domain, the frequency-broadening operators of the curve fitting amplitude spectrum of the high-frequency logging record amplitude spectrum are obtained to perform frequency-broadening processing of the wavelet domain data in the frequency band range, and the wavelet domain data is subjected to wavelet reverse transformation to a time domain to obtain high-resolution and high-precision converted-wave data; and moreover, and the converted-wave data after the frequency band broadening is subjected to the velocity inversion to obtain finer inversion results. The method for improving converted-wave seismic data resolution and the velocity inversion method thereof can obtain high-resolution and high-precision converted-wave seismic data and can obtain finer inversion results.

The invention relates to a gas reservoir survey technology, and in particular relates to a PP-PS joint inversion system based on Kalman filtering. A Kalman filtering model is added to the subject of an AVO joint inversion model containing noise. The noise-containing AVO joint inversion model comprises a vector m used for surveying geological meaning attribute information, wherein the vector m comprises longitudinal wave velocity alpha, shear wave velocity beta and a density term rho. The Kalman filtering model comprises time update and measurement update. The optimally estimated vector m acquired through the time update and the measurement update is used to acquire the longitudinal wave velocity alpha, the shear wave velocity beta and the density term rho. The optimally estimated vector mis more accurate than a conventional vector m without the Kalman filtering model, and the survey result is more reliable. The problem of inaccurate density and shear wave velocity inversion caused byconventional AVO inversion based on longitudinal wave reflection data in the prior art is solved.

The invention discloses a drilling guidance method, system and device based on an earthquake while drilling and a storage medium. Rock debris generated in the drilling process is collected; digital processing is carried out; obtaining core pore structure model, the physical property parameter information of the stratum encountered in the drilling process is provided in real time through the digital rock debris technology, the drilling position can be rapidly and accurately judged and predicted, very accurate stratum data and a stratum speed model can be provided for processing of seismic drilling data while drilling, and the purpose of guiding on-site drilling decisions is achieved. Besides, the digital rock debris information is used as the supplement of the seismic drilling data while drilling, so that the establishment of an initial velocity model can be realized more finely, the horizon, velocity and anisotropy constraints of the digital rock debris are increased on the basis of aconventional velocity inversion formula, the seismic data processing quality is greatly improved, and the precision of the seismic technology while drilling is improved.

The invention, which belongs to the field of velocity modeling of passive source seismic detection, relates to a joint velocity inversion method based on passive source seismic waveform and reverse time imaging thereof. The method mainly comprises the following steps: step one, preprocessing seismic data and extracting seismic source wavelets; step two, calculating a reverse time continuation wavefield, and carrying out reverse time imaging and seismic source positioning; step three, calculating the difference between a theoretical seismic record and an observed seismic record; step four, establishing an objective function of an inversion speed; step five, on the basis of an adjoint state method, calculating a gradient of the objective function on model parameters as well as an updating direction and step length; step six, updating a longitudinal wave velocity model and a transverse wave velocity model; and step seven, determining whether iteration termination conditions are met or not; and if so, outputting a positioning result and the velocity models; and otherwise, returning to the step two. A high-resolution velocity model is obtained under the circumstance that the focus position is unknown.

The invention provides a deep rock mass quality detection method based on seismic waves while drilling and related equipment, and the method comprises the steps: obtaining a seismic wave signal while drilling through a first seismic detector installed at the front end of a drill rod, and obtaining a seismic wave response signal on the surface of a detected deep rock mass through a second seismic detector arranged around a drill hole; obtaining a cross-correlation function signal through the seismic wave signal while drilling and the seismic wave response signal; a frequency dispersion curve is obtained based on the cross-correlation function signal, surface wave frequency dispersion inversion is carried out based on the frequency dispersion curve, and a transverse wave speed model of rock mass around the drill hole is obtained; longitudinal wave arrival time is determined based on the cross-correlation function signal, longitudinal wave velocity inversion is carried out based on the longitudinal wave arrival time, and a longitudinal wave velocity model of rock mass around the drill hole is obtained; based on the transverse wave velocity model and the longitudinal wave velocity model, the development characteristics of the structural surface of the deep rock mass are identified, so that the test can be completed in the drilling process of the drill rod, and the quality of the rock mass around the drill hole can be accurately detected.