71 results about "Seismic migration" patented technology

The invention relates to a method for directly generating angle gather by using wave-equation migration, which is applied to seismic data processing in seismic exploration and is a method for forming the wave-equation pre-stack depth migration of the angle gather of seismic migration. The method directly utilizes shot-domain migration results for generating the angle gather imaged by an underground reflecting interface by calculating the incident angle of a seismic source outgoing wave at an underground imaging point, and compensates the change of the nonuniform coverage of an observing system for amplitude. The angle gather directly corresponds to the parameter changes of physical properties of target layers and provides accurate angular-domain seismic reflecting strength for pre-stack inversion. The method has the core that because the incident angle of a seismic source wave field is determined by directly using a single-route wave algorithm, the method is better matched with a wave-equation migration method while avoiding the instability of a ray method. Compared with migration calculation, because only the simple-harmonic wave field of the single-route wave is utilized for the calculation of the incident angle, the metering amount in the method can be ignored. The method can be applied to two-dimensional and three-dimensional wave-equation pre-stack depth migration treatment and has an important application value in the explorations of oil gas resources and mineral resources.

A seismic processing method to solve an eikonal equation to determine a travel time (t) of a sound wave between a seismic source at a first set of coordinates (x2,y2, z2) and a point underground at a second set of coordinates (x,y,z), comprising determining a distance between the seismic source and the point underground; obtaining a propagation time between the seismic source and the point underground; calculating a velocity variable (v) as a ration of the distance between the seismic source and the underground point divided by the propagation time between the seismic source and the point underground; and extrapolating on the velocity variable to obtain a travel time.

The present invention discloses an anisotropic multi-wave Gaussian beam prestack depth migration imaging method, which is suitable for two-dimensional anisotropic media. The anisotropic multi-wave Gaussian beam prestack depth migration imaging method comprises: obtaining a ray tracing equation group based on anisotropic ray tracing; using the ray tracing equation group to realize ray tracing of P wave and S wave in the two-dimensional anisotropic media; introducing the anisotropic ray tracing to a Gaussian beam migration method, and carrying out cross-correlation imaging by using a wave field which extends forwardly at a seismic source and a wave field which extends reversely at a beam center, so as to realize Gaussian beam prestack depth migration of PP wave and the PS wave in the anisotropic media. The present invention solves the problem that existing seismic migration technologies are affected by anisotropy.

The invention provides a seismic migration method and device for steep-dip stratums and fractures. The method comprises the following steps: inputting seismic data; defining an underground horizontal reflection layer of a foundation; generating CDG (common detector gather) seismic data; carrying out layer-by-layer continuation processing on CSG (common-shot-gather) seismic data by using an amplitude-preserved Fourier finite-difference continuation operator; calculating travel time in the migration of a HV-type dual-reflected wave by using a finite-difference travel-time calculating method; carrying out layer-by-layer imaging on the HV-type dual-reflected wave; carrying out layer-by-layer continuation processing on the CDG seismic data by using the amplitude-preserved Fourier finite-difference continuation operator; calculating travel time in the migration of a VH-type dual-reflected wave by using the finite-difference travel-time calculating method; carrying out layer-by-layer imaging on the VH-type dual-reflected wave; carrying out superimposed imaging on the migration results of the HV-type dual-reflected wave and the VH-type dual-reflected wave so as to obtain an imaging result of steep-dip stratums and fractures in a target zone. The method disclosed by the invention has high calculation efficiency and can be used for obtain a high-quality imaging result of steep-dip stratums and fractures.

The invention relates to a least square reverse time migration gradient precondition method based on a direct wave field, belongs to the field of seismic migration imaging. The method comprises the steps that: a seismic record is obtained by adopting the sound wave equation finite difference linearization forward modeling technology based on a background speed model and a reflection coefficient model in each iteration process of least squares reverse time migration, then timing 'approximate direct' wave field energy with shot point seismic source wavelets as disturbance and reverse 'approximate direct' wave field energy with the above seismic record obtained by linearization forward modeling as disturbance are obtained by simulation by using the non-reflection acoustic wave equation finitedifference forward modeling technology, and finally, the timing 'approximate direct' wave field energy and the reverse 'approximate direct' wave field energy are applied to perform precondition processing on the gradient. Model experiment results show that the defect of inaccurate wave field energy in a conventional gradient precondition method based on seismic wave energy can be effectively overcome, the precision of the gradient precondition is improved, so that the imaging effect of least square reverse time migration is remarkably improved.

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 relates to a flat spot mapping method by using complex two dimensional seismic data which is processed by petroleum exploration. The process is that the data which requires the spatial correction is collected; the correction value of the initial space is obtained according to the level data; if the place with a complex structure before spatial correction is not located at the same wing part with the place after the spatial correction, a new spatial correction value is obtained. The speed variation parameter S of seismic migration is determined according to the inclination degree of the strata; the slope product of the projection points of the two points before and after spatial correction on the time level variation map along the migration direction is a positive number; When S is selected, the correction coefficient R parameter value of seismic migration speed of a certain underground point is determined. The invention greatly solves the excessive migration problem of the calculation result by using the original method; the whole spatial correction result is more accurate and reasonable, which can really reflect the shape of underground structure; the invention is favorable to comprehensive geological evaluation and oil and gas prediction.

The invention provides a method for probing hidden trouble of a pile bottom before pouring a pile foundation and a probing device thereof. Sensors are arranged in a lateral array with the central axisof a pile hole as the center under the surface of the liquid in the pile hole before pouring the pile foundation to form a horizontal sensor surface array. Seismic source points are arranged in a vertical array below the horizontal sensor surface array with the central axis of the pile hole as the center to form a vertical array seismic source point. The signal is emitted through the seismic source, and seismic waves are emitted through the seismic source points. The sensors receive the seismic waves and transmit the signal to a multi-channel synchronous seismograph. The multi-channel synchronous seismograph receives the signal to complete data acquisition. The method for probing the hidden trouble of the pile bottom before pouring the pile foundation and the probing device thereof can obtain the seismic records beneficial for separating the up and down waves of the seismic waves in the unpoured pile hole, and obtain the relevant information of the hidden trouble of the engineering geology of the pile foundation and the pile bottom by a traveling wave separation algorithm and a seismic migration imaging algorithm, so that the extraction and processing of the subsequent informationare facilitated to obtain the the hidden trouble of the engineering geology of the pile foundation and the pile bottom.

The invention relates to a fault seismic interpretation method, and belongs to the technical field of the oil exploration. The fault seismic interpretation method comprises the following steps: firstly determining a time-depth conversion relation of well drilling strata and a well bypass seismic section, and then establishing the time-depth conversion relations of all wells in a target work area;firstly interpreting a seismic main section and a contact section by utilizing the established time-depth relation conversion of all wells and the seismic in the work area; initially determining a trajectory location of the target fault on the main section and the contact section, and then determining fault trajectories on an uplifted side seismic section and a downthrown side seismic section, andmodifying and interpreting the target fault trajectories on the seismic main section and the contact section by utilizing the determined target fault trajectories on the uplifted side seismic sectionand the downthrown side seismic section parallel to the target fault. Through the seismic interpretation method of the fault disclosed by the invention, the seismic interpretation precision is greatly improved, and the method has significance for the refined development of the oilfield maturing field.

The invention relates to a seismic migration method for a coupled transmission coefficient, which comprises the following steps of: 1) dividing different depth layers by taking the earth surface as an initial point, namely dividing underground media to be explored into different depth layers according to different depth intervals, and assuming the different depth intervals of the underground media to be explored as different horizontal sheets, wherein the thickness of the horizontal sheets is the depth interval of the underground media to be explored; 2)based on a Lippmann-Schwinger integral equation, solving the Lippmann-Schwinger equation by establishing an integral equation of an upper boundary gamma1 and a lower boundary gamma2 of a seismic wave field in in the closed area omega of any horizontal sheet; 3) establishing a boundary integral equation at the lower boundary gamma2 of the closed area omega according to a transmission effect of the lower boundary gamma2 of the horizontal sheet; and 4) solving a seismic migration wave field according to the transmission and reflection effects between the horizontal sheets and of the upper boundaries and lower boundaries of the horizontal sheets. The seismic migration method can be widely applied to a seismic migration technology for imaging a complex oil exploration structure.

Explicit depth extrapolation operators are constructed with variable operator lengths depending on maximum dip angle, accuracy condition, and wavenumber. Operator tables are then constructed using the explicit depth extrapolation operators. In a further embodiment, depth migration is performed using the explicit depth extrapolation operators from the operator tables.

The invention discloses a denoising method based on well logging-seismic combination. The method is characterized in that relationship is established between synthesis records manufactured by well logging information and seismic information, noise in the seismic information is removed, and the signal to noise ratio of the seismic information is increased. Because the seismic information, especially a high-frequency component, is submerged into the noise and the finding of a noise rule is difficult, the conventional denoising method only utilizes the seismic information per se, so that the removal of the noise is difficult. The denoising method has the advantages that the synthesis records obtained by converting the acoustic wave well logging information are regarded as noise-free expected output, and a seismic record is used as input; when mathematic relationship between the synthesis records and the seismic record is established, an effective signal is enhanced, a noise signal is weakened, and the purposes of denoising and increasing a signal to noise ratio are realized; by combining the synthesis records of the well logging information and the seismic record, the nonregular noise can be removed.

The embodiment of the invention discloses a seismic migration imaging method and device. The method comprises the following steps: obtaining seismic data, determining imaging velocity field data and quality factor field data according to the seismic data; calculating ray path compensation travel time according to the quality factor field data; obtaining a travel-time table, a compensation travel schedule and prestack seismic trace data corresponding to the seismic data; compensating the prestack seismic trace data according to the travel-time table and the compensation travel schedule; generating an imaging result according to the compensated prestack seismic trace data. According to the seismic migration imaging method and device disclosed by the embodiment of the invention, the accuracy of the migration imaging result can be improved.

The invention discloses a seismic simulation shaking table test control method for cross-fault seismic waves. A power part and a pseudo-static part of cross-fault seismic waves are separated through afiltering method, high-frequency acceleration is input into a system in order to obtain a high-frequency displacement driving signal, and a low-frequency pseudo-static displacement time history is superimposed on the basis, so that a wide-frequency displacement driving signal is obtained and is input into the shaking table control system, a shaking table is controlled, and shaking table test simulation of the cross-section seismic waves is completed. According to the methods, the requirements of the two aspects of the acceleration and the pseudo-static displacement of the cross-fault seismicwaves are both considered, and the seismic simulation shaking table for the cross-fault seismic waves can be accurately reproduced.

The instant invention is designed to provide an adaptive approach to removing short-period time/phase distortions within a downward-continuation process that is a key component of seismic migration algorithms Using techniques analogous to residual statics corrections that are used in standard seismic processing, one inventive approach estimates and removes the effects of short wavelength velocity disruptions, thereby creating clearer seismic images of the subsurface of the earth. Additionally, the instant method will provide an updated velocity model that can be used to obtain further image improvement.

The invention relates to a method for the quantitative analysis and evaluation of vertical resolution of a three dimensional seismological observation system, and the method is characterized in that the method comprises the following steps: 1), giving a complex speed model, a to-be-evaluated seismological observation system and the position information of an underground target point, carrying out the wave field extension of the seismological observation system under the complex geologic conditions, and obtaining the frequency domain wave field information transmitted from the underground target point to each ground detection point; 2), respectively carrying out the vertical co-focusing of the frequency domain wave field information of all ground detection points, and obtaining the co-focusing result of each ground detection point at the underground target point; 3), calculating and obtaining a co-focusing result of the whole seismological observation system; 4), calculating a main lobe width according to the vertical co-focusing result; 5), calculating a main lobe amplitude occupancy ratio according to the main lobe width; 6), carrying out the analysis of the seismic migration imaging of the seismological observation system according to the obtained main lobe width and the obtained main lobe amplitude occupancy ratio. The method can be widely used in the design and analysis of the seismological observation system.

The invention discloses a VSP initial velocity modeling method and device. The VSP initial velocity modeling method comprises following steps of picking up seismic wave first arrival time from VSP data; inverting discrete velocity values based on the seismic wave first arrival time; obtaining a seismic migration section based on ground seismic data; carrying out interpolation on the discrete velocity values by taking the seismic migration section as the guide in order to establish a velocity model. With respect to the VSP initial velocity modeling method and device, by combining the VSP and the ground seismic data, the VSP initial velocity is modeled relatively accurately.

The invention discloses a method of predicting spatial distribution of channel sand by seismic attributes, which belongs to the field of oil and gas geophysical prospecting engineering. The method comprises steps: logging data and seismic data in a target reservoir area are acquired, well seismic demarcation is carried out and a target layer is determined; according to the seismic data of the target layer, a cubic spline encrypted sampling method is used to obtain a high-density seismic data volume; and according to the high-density seismic data volume and the logging data, a seismic sensitiveattribute volume and seismic attribute slices are obtained, the zero point position of the seismic attributes is determined, and the quantitative relationship between the seismic attributes and the channel sand body position and the thickness is further determined. The prediction on the spatial distribution of the channel sand by the seismic attributes changes to more accurate quantitative analysis from qualitative description, the error range of a seismic attribute sand thickness prediction result demarcated by the actual logging data is reduced, and the scope of using the seismic attributesto predict the distribution of thin-layer channel sand and carry out quantitative evaluation is widened.

The invention relates to a micro-seismic migration imaging positioning method based on multiplication of waveform cross correlation coefficients, and belongs to the technical field of oil-gas reservoir fracture micro-seismic monitoring. The method includes the following steps of: preprocessing actual micro-seismic data; performing subsurface imaging point division, and calculating the travel timeof all imaging points to each receiving point on the ground; for a certain imaging point, eliminating the arrival time difference of the imaging point to different receiving points, calculating the cross-correlation coefficient of a micro-seismic record after the time difference correction; calculating the cross-correlation energy value E of the imaging point; repeating the third and fourth stepsto obtain the energy values E of all underground imaging points; and setting an energy threshold E0, obtaining the imaging point position of an energy maximum value greater than the energy threshold as the occurrence position of a micro-seismic source. The method realizes the dual-effect suppression of the noise by using the form of multiplication of the waveform cross-correlation coefficients soas to greatly improve an anti-noise capability, avoids the interference of the first arrival polarity on the positioning imaging results, has high calculation efficiency and satisfies the real-time monitoring of the micro-seism.

The invention discloses a monitoring method for real-time evaluation of the seismic intensity. Data including geological and building information of each target area are collected; statistics of information including related earthquake magnitudes and epicentral distances of historical earthquake cases and the like is carried out; a fitting curve for evaluating the seismic intensity is drawn underthe parameters; and then an off-site monitoring and early warning network system is set in a seismic zone region and the seismic information including the earthquake magnitude and the epicentral distance and the like is obtained timely at the occurrence of the earthquake by combining the seismic information collected by a local seismic wave monitoring instrument; and according to the seismic information, the possibilities of seismic intensity levels in all target areas are evaluated rapidly and accurately by combining the fitting curve of the seismic intensity.

The invention provides an analysis method and apparatus of wide-azimuth seismic migration speed, and relates to the technical field of geological prospecting. The analysis method of wide-azimuth seismic migration speed includes the steps: obtaining trace gather data after performing offset processing on an offset vector sheet; classifying the trace gather data after performing offset processing on the offset vector sheet according to an azimuth angle, and obtaining the azimuth angle trace gather data of the preset number through classification; performing residual speed scanning processing on each azimuth trace gather data, and obtaining the speed scanning result; and performing dual-path integral stacking processing on the speed scanning result so as to extract the speed parameters of each azimuth trace gather data and obtain the speed model of each azimuth trace gather data. Therefore, the analysis method and apparatus of wide-azimuth seismic migration speed relieves the technical problem that in the prior art, the efficiency of eliminating azimuthal anisotropism is relatively lower.

The invention provides a waveform indication inversion beach body prediction method. The prediction method comprises: acquiring seismic migration data, seismic horizon data, drilling data and loggingdata; acquiring an accurate time-depth relationship by using a well-seismic calibration method, and converting a depth domain logging curve into a time domain logging curve; analyzing and obtaining asensitive time domain logging curve, and obtaining an initial frame model through the sensitive time domain logging curve; analyzing and obtaining inversion parameters suitable for the beach body prediction, and obtaining inversion result data body through the seismic migration data and the initial frame model; obtaining a response range corresponding to the beach body through the sensitive time domain logging curve, and extracting data representing the beach in the inversion result data body according to the inversion result data body and the corresponding response range of the beach body, and obtaining the beach prediction result. The method according to the invention can predict the beach body more accurately, and can play an important guiding significance for reservoir and oil and gasprediction.

A method for processing seismic data includes obtaining a velocity model, determining a critical angle for an interface represented in the velocity model based on a ratio between velocity of the seismic wave on first and second sides of the interface, determining an orientation of a normal vector extending normal to a location of the interface, determining an orientation of an arrival direction vector of a wavefield at the location of the interface, calculating an angle between the normal vector and the arrival direction vector, determining that the angle between the normal vector and the arrival direction vector is greater than the critical angle at the location, and attenuating the wavefield associated with the location in response to determining that the angle between the normal vector and the arrival direction vector is greater than the critical angle at the location.

The invention discloses a mixed domain seismic migration Hessian matrix estimation method, and relates to the technical field of exploration geophysics, and the method comprises the steps: firstly obtaining an initial imaging result through employing a conventional migration method, then taking the migration result as a reflectivity model, carrying out the linear forward modeling and migration, and obtaining a secondary imaging result, using the two offset results for estimating an unstable phase filter in a space-wavenumber domain for approximating a Hansen matrix, calculating the inverse of the Hansen matrix by using mixed domain deconvolution, and using the estimated inverse of the Hansen matrix as a functional gradient in least square offset to improve the convergence rate of inversion, so that the inversion accuracy is improved. And the least square inversion is converged to an accurate solution within 4-5 iterations. The method has the advantages that the method is high in calculation efficiency, the least square migration convergence speed can be increased, the calculation cost of least square reflectivity inversion is reduced, and the method has good application prospects.

The invention discloses a method for correcting the volume of a carbonate fracture vug, which includes the following steps: carrying out 3D sonar scanning measurement on the contour of a karst cave, and collecting an actual migration data body of the karst cave; building a 3D seismic geological model of the karst cave, and carrying out forward simulation trial calculation on the 3D seismic geological model to get a seismic migration imaging data body; using the seismic migration imaging data body and the actual migration data body to extract a seismic attribute body of the 3D seismic geologic model; and calculating the apparent volume of the karst cave, and correcting the volume of the karst cave according to the correlation relationship between the apparent volume of the karst cave and the actual volume of the karst cave obtained through 3D sonar scanning measurement. By analyzing the volume relationship of seismic attribute, a forward model and a known karst cave, the volume of the karst cave can be corrected, the volume of a fracture vug can be calculated accurately, and the difference between the amount of recoverable resources of carbonate oil gas and the actual yield can be reduced.

The invention provides a seismic migration imaging method and device, the method comprises the following steps: establishing a wave field residual target function based on the seismic observation dataand the analog data to be solved; determining the current wave field residual value in combination with the current reflection coefficient model and the wave field residual target function; the migration method based on time-shifted imaging condition migrates the residual value of the current wave field and obtains the gradient of the objective function; determining the updated reflection coefficient model by adopting a conjugate gradient method based on the target function gradient; carrying out updating iteration on the updated reflection coefficient model, which is used as a current reflection coefficient model until the preset iteration number is reached. The target reflection coefficient model is obtained, and then the migration imaging results are obtained. The method adopts the least squares method, the accuracy of the seismic migration imaging is effectively improved, the imaging effect is good, time-shifted imaging conditions are used in the migration imaging process, the calculation amount is small, the migration imaging efficiency is improved, technical problems of low efficiency and poor imaging effect of traditional migration imaging is solved.