161 results about "Seismic wave propagation" patented technology

Systems and methods provide for detection of one or more underground utilities. Radar waves and seismic waves of about the same wavelength are generated and communicated into a subsurface. Radar and seismic response signals resulting from communication of the radar and seismic waves into the subsurface are concurrently received. Data associated with the received radar and seismic response signals are stored. One or more underground utilities within the subsurface is/are detected using the stored data. The underground utilities may include metallic and non-metallic utilities.

The invention relates to methods and computer-readable medium to implement computing the propagation velocity of seismic waves in the earth. The invention computes the true propagation velocity of seismic waves in the earth, which is a condition of obtaining an accurate image of subsurface geology that can be used to prospect for oil and gas deposits. In an embodiment, the method of computing the propagation velocity of seismic waves in earth, includes providing an estimate of the propagation velocity, generating a time shift gather using a depth migration at a plurality of locations of the earth, converting each of the time shift gathers to a semblance gather, transforming each semblance gather into a velocity gather whose energy peaks represent a root-mean-square average of the propagation velocity along the forward and backward path between earth's surface and a point of the subsurface geology, and converting the energy peaks to the propagation velocity.

The invention provides an anisotropic three-dimensional prestack time migration method which is applied to processing reflection seismic data in seismic exploration and relates to a prestack time migration method aiming at three-dimensional seismic data acquisition. The method takes into account the effect of the velocity anisotropy of an earth medium on the travel time and the amplitude value propagated by a seismic wave and can independently determine the migration velocity and the anisotropic parameters during the migration process, therefore, a migration image which is accurately homed and is preserved in amplitude is obtained. The method determines the three-dimensional time-varying migration aperture in an anisotropic medium according to an underground structure time-varying inclination angle and can simultaneously press the migration noise during the migration process. With the adoption of the method, the efficient and parallel calculation is realized through reasonable distribution of the seismic data among compute nodes of a cluster computer. The method has the key point that the travel time, the amplitude value and the imaging weight coefficients of the seismic wave and an incident angle in the anisotropic medium are solved with the application of a one-way wave operator with deep migration and the steady phase point principle; and has the important application value for oil-gas and mineral resource exploration.

A method for performing pre-stack time migration of seismic data in a region where the subsurface seismic wave propagation velocity varies in both the vertical direction and a horizontal direction. The migration is performed in the wave number—frequency domain and involves using travel time maps to find a linear fitting of the migration phase shift for a given ray parameter and at a given vertical depth versus horizontal position. The slope and intercept parameters from the linear fit are used to adjust a known pre-stack time migration equation, with the accuracy of the linear approximation requiring mild horizontal velocity variation.

The invention discloses a blast construction method of a shallow-buried railway tunnel in underneath pass of civil house weak segments. The method includes the following steps that a, according to characteristics of the shallow-buried railway tunnel in underneath pass of the civil house weak segments, a numerical value model is established; b, material parameters corresponding to the numerical value model of the shallow-buried railway tunnel in underneath pass of the civil house weak segments are selected; c, blasting simulation of the shallow-buried railway tunnel in underneath pass of the civil house weak segments is performed; d, numerical value simulation results of different cutting blasting modes are analyzed; e, in combination with engineering measured data of blasting constructionfor the shallow-buried railway tunnel in underneath pass of the civil house weak segments, verification is performed so that the demands of blasting safety vibration control standards can be met. By the utilization of a power finite element method, numerical value simulation analysis is performed to research the rule of a blasting seism, verification is performed in combination with the engineering measured data, and therefore blasting vibration is reflected accurately to a certain degree. The blasting vibration reduction effect of a vibration reduction technical scheme is researched, bases are provided for making a vibration reduction blasting scheme for the tunnel in underneath pass of dense civil houses, and influences on the rule of seismic wave propagation by excavation of the tunnelare researched.

The invention discloses a forward simulation method and system of a three-dimensional seismic wave field based on GPU parallel acceleration and belongs to the technical field of numerical simulation and high-performance computing. According to the method, high-order finite difference is conducted on a seismic wave propagation equation, high-precision explored seismic wave propagation data is obtained through numerical simulation calculation, acceleration processing is conducted on a GPU, and ground seismic recorded data and wave field section results are efficiently generated in a high-precision mode. By adopting the forward simulation method and system, the three-dimensional seismic wave equation can be calculated in a high-precision and high-efficiency mode, the computational efficiency is greatly improved, and the computational accuracy is effectively improved.

The invention discloses a near-surface tomographic velocity analysis method. The near-surface tomographic velocity analysis method comprises the following steps: picking up travel time of first arrival by aiming at pre-stack data, and obtaining an initial model reflecting underground medium velocity distribution by pre-stack processing; performing a shortest path ray tracing method on the model to obtain simulated travel time; performing wave field simulation on the model by utilizing a frequency domain wave equation to obtain a sensitive kernel function reflecting disturbance of a medium to the travel time; establishing a corresponding inversion equation and solving to obtain a slowness updating amount. According to the tomographic velocity analysis based on the Fresnel zone, the problem that the solution of a large-scale sparse matrix is instable during the traditional temographic velocity analysis based on the ray theory is solved, and the seismic wave propagation rule is more truly portrayed; the near-surface tomographic velocity analysis method has the advantages that the physical geography significance is obvious, the stability is strong, the efficiency is high, and calculation results are more real and reliable.

The invention relates to methods and computer-readable medium to implement computing the propagation velocity of seismic waves in the earth. The invention computes the true propagation velocity of seismic waves in the earth, which is a condition of obtaining an accurate image of subsurface geology that can be used to prospect for oil and gas deposits. In an embodiment, the method of computing the propagation velocity of seismic waves in earth, includes providing an estimate of the propagation velocity, generating a time shift gather using a depth migration at a plurality of locations of the earth, converting each of the time shift gathers to a semblance gather, transforming each semblance gather into a velocity gather whose energy peaks represent a root-mean-square average of the propagation velocity along the forward and backward path between earth's surface and a point of the subsurface geology, and converting the energy peaks to the propagation velocity.

The invention discloses a detonation control method for reducing blasting vibration effect, which uses digital electronic detonators to reduce blasting vibration effects by controlling the number of each detonator section. One is: the selection of the number of detonator segments adopts the principle of mutual interference between blasting vibration peaks and troughs to reduce vibration, specifically: the delay time between the holes of each row of blast holes adjacent to the detonator detonator ΔTi = T/2-1000*a/c, where T is the main vibration period of the blasting vibration, in milliseconds; ΔTi is the delay time between adjacent blastholes for sequential detonation, in milliseconds; a is the distance between blastholes, in meters; c is the propagation velocity of seismic waves in rocks, The unit is m/s; the inter-row delay between adjacent rows: ΔTj=nΔTi, ΔTj is the inter-row delay time, and the unit is millisecond; n is the number of adjacent front row detonator segments. The second method is: the selection of the number of each detonator section adopts the principle that the blasting vibration waves are independent of each other and vibration does not superimpose, that is, the inter-hole delay ΔTi=(1.0~1.5)t of sequentially detonating adjacent detonators.

The invention relates to a dispersion curve extracting method for a mine channel wave double-component seismic signal. The dispersion curve extracting method comprises the steps of firstly acquiring a Love channel wave signal from the mine channel wave double-component seismic signal; performing generalized S transformation on the acquired Love channel groove signal for obtaining a relationship diaphragm between group speed and frequency of the Love channel wave; drawing a line between maximal vibration amplitudes in the relationship diaphragm between the group speed and the frequency, and utilizing the obtained curve as the dispersion curve. According to the dispersion curve extracting method, the width of a Gauss window in S transformation is changed by means of a linearly changed adjusting parameter, thereby improving precision of a channel wave signal dispersion curve. Furthermore, according to the method, before generalized S transformation, propagation direction and polarization angle of the seismic wave are determined through calculation according to an energy distribution criterion of a longitudinal wave in the acquired signal in a double-component detector. Coordinate rotation is performed for obtaining the Love channel wave signal which horizontally vibrates in the propagation direction of the vertical wave. Then dispersion calculation is performed on the signal. The dispersion characteristic of the obtained dispersion curve is more accurate.

One aspect of the invention is a method for building geologic/stratigraphic models of the earth for the purposes of numerical simulations of phenomena of interest, such as seismic wave propagation, or fluid flow, reservoir simulation, etc. An embodiment of the invention uses stochastic methods to create material property models that have desired statistical properties by numerically simulating deposition of geological layers. The method can create multiple material parameter models from numerical implementations of a variety of geological processes.

The invention discloses a cladded optical fiber grating vibration sensor. A semiconductor laser is connected with an optical fiber circulator by single-mode optical fibers; the optical fiber circulator is connected with an optical fiber grating sensor and an optical fiber wavelength division multiplexer by the single-mode optical fibers; the optical fiber wavelength division multiplexer is connected with a cladded grating photoelectric detector and a fiber core grating photoelectric detector by the single-mode optical fibers; the cladded grating photoelectric detector and the fiber core grating photoelectric detector are connected with an oscilloscope by coaxial cables; a fiber core gratings is written on thin-core optical fibers; cladded gratings are written on optical fiber claddings. During shock detection of a building, laser emitted by the semiconductor laser is transmitted to the fiber core gratings and the cladded gratings through the optical fiber circulator, vibration of a to-be-detected vibrating body leads to changes of cladding energy distribution reflected by the cladded gratings and changes the energy which enters the single-mode optical fibers in a coupled manner, so that information of vibration direction is obtained, structural deformation of civil engineering such as bridges, tunnels and dams can be detected in real time, and interior structure of earth and earthquake wave propagation characteristics can be researched in order to predict impending earthquake.

The present invention provides a PML (Perfectly Matched Layer) boundary three-dimensional seismic wave propagation simulation method utilizing CUDA (Compute Unified Device Architecture), comprising the steps of: reading in an initial parameter and a Ricker wavelet; decomposing a stress in a first acoustic wave fluctuation equation of a three-dimensional seismic wave into stress components in three directions which are mutually perpendicular, and adding a PML boundary condition to form a second acoustic wave fluctuation equation; using a finite difference method to discretize the second acoustic wave fluctuation equation, so as to form a finite difference acoustic wave fluctuation equation; bordering a first three-dimensional speed model to form a second three-dimensional speed model; calculating attenuation coefficients of edges, angles and surfaces of the second three-dimensional speed model in a CPU (Central Processing Unit) according to the finite difference acoustic wave fluctuation equation; calculating stresses of net points of the second three-dimensional speed model in a GPU (Graphics Processing Unit) according to the attenuation coefficients; and outputting a three-dimensional seismic wave simulation record at the last moment according to the stresses. The PML boundary three-dimensional seismic wave propagation simulation method of the present invention can achieve high speed-up ratio and shorten simulation time.

The invention provides a ground microseism monitoring anisotropy speed model and an automatic construction method thereof. The automatic construction method comprises: S1, constructing and calculating a nine-parameter speed model; S2, automatically regulating an initial speed; and S3, employing a cross validation method to calibrate speed model parameters. Compared with a traditional horizontal layer speed model, the speed model of the invention can embody the change trend of the speed with seismic wave propagation directions in a better way, and better simulate real seismic wave propagation, thereby building a more accurate speed model; through the speed model, positioning accuracy is higher; the speed model can automatically adjust an initial speed, thereby avoiding the trouble of artificially adjusting the initial speed, and determining the initial speed more efficiently; the speed model parameters are corrected by employing the cross validation method, the reciprocal value of positioning errors is used as a weight to linearly superpose speed model parameters of all sets, and corrected speed model parameters can improve positioning precision effectively.

The invention relates to a land-use four-component digital geophone. In the prior art, a seismic wave propagation characteristic can not be finely researched. By using the geophone of the invention, the above problem is solved. The geophone is a four-component geophone formed by a three-component MEMS acceleration geophone and a moving-coil velocity geophone. The geophone is formed by a micro electromechanical system earthquake three component acceleration sensor, a weak signal detection and feedback circuit, a moving-coil geophone, a digital unit, a control module CM, a data communications unit and a power module PM. The micro electromechanical system earthquake three component acceleration sensor and the weak signal detection and feedback circuit are used to complete acquisition and digital functions of an acceleration parameter. The moving-coil geophone and the digital unit are used to complete the acquisition and digital functions of a velocity parameter. The geophone possesses the advantages that a signal acquisition and receiving function of the one velocity parameter and the three-component acceleration parameter can be performed on a same receiving point; the seismic wave propagation characteristic can be finely researched; exploration precision is greatly increased.

The invention discloses a method for calculating the propagation speed of earthquake waves in a mine region by utilizing a microearthquake point as an earthquake source, comprising the following steps: determining the coordinate estimated value of the microearthquake point according to the earthquake wave time generated by the microearthquake point measured by multiple preset sensors; determiningall possible propagation paths of the earthquake waves generated by the microearthquake point to the preset sensors according to the coordinate estimated value of the microearthquake point and the speed layer where the preset sensors are; selecting the possible propagation path with the difference between the earthquake wave propagation time and the earthquake wave time measured by the preset sensors corresponding to a preset range from all the possible propagation paths as a fixed propagation path; and calculating the propagation speed of the earthquake waves according to the determined fixed propagation path and the initial value of a three-dimensional continuous speed diamond on the fixed propagation path.

The invention provides a normal moveout stretch cutting method for processing geophysical exploitation seismic data. According to the method, a stacking velocity field is utilized, average speed is calculated, or interval velocity is calculated after smoothing the average speed. Further, by using the velocity and shot-geophone distance information, approximate calculation of an incident angle is performed according to the theory of ray (straight ray or curved ray) propagated by seismic wave, and a 1D or 3D space varying incident angle threshold value reference is used as a standard of measurement to determine the cut of each seismic channel. Thus, more accurate automatic cutting of the normal moveout stretch is realized, the interference caused by net normal moveout stretch can be cut, effective wave amplitude can also be protected to the greatest extent, and finally, the resolution and the signal-noise ratio of a stacked section are improved.

The invention relates to a static correction method and a static correction device for a converted wave. The method comprises the following steps: carrying out pretreatment on multi-wave seismic data; obtaining the correcting value of field shot points and the correcting value of geophone; correcting the seismic data; carrying out separation and speed analysis on the seismic data after correction to generate the propagation speed of the seismic data; carrying out correction and excision operation on a trace gather to generate dynamic correction trace gather data; converting the CMP trace gather data of PP wave into PS domain, overlapping the CMP trace gather data of PP wave converted into the PS domain; selecting a goal layer on the overlapped seismic data, and carrying out position pickup on the goal layer to obtain position time; presetting a reference plane, and calculating the time difference of the position time and the preset horizontal reference plane time; correcting the dynamic correction trace gather data onto the preset reference plane, and generating the PP wave dynamic correction trace gather data after construction leveling; carrying out geophone trace gather separation and trace gather overlapping on the dynamic correction trace gather data after construction leveling, and generating geophone trace gather overlapped data after construction leveling.

The invention provides an orthotropic dielectric fluid factor and fracture parameter inversion method. The method comprises the following steps: deducing a rigidity matrix of an ortho-symmetric anisotropic fracture medium by using a vertical transverse isotropic medium under a dry rock background according to fracture weakness; with utilization of hypotheses of weak anisotropy and small fracture weakness, deducing a new expression of weak anisotropy approximate rigidity of a saturated fluid rock in an orthogonal medium by combining an anisotropy Gassmann equation; acquiring a PP wave linearized reflection coefficient for fluid and fracture parameter decoupling in the orthogonally symmetrical weak anisotropic medium by combining stiffness disturbance and scattering theories; and with logging information as prior information, realizing elastic impedance pre-stack inversion changing with offset and azimuth angle by using a partial incident angle stacked by azimuth seismic data under Bayesian framework. According to the invention, Reliable results can be provided for fluid identification and fracture characterization; and technical supports are provided for seismic wave propagation research, oil and gas development and seismic disaster prevention.

The invention discloses a multi-core multi-node parallel three-dimensional seismic wave field generation method and system. High-precision and high-efficiency solving of a three-dimensional seismic wave equation can be realized based on high-order finite difference and multi-core multi-node parallel acceleration. The method comprises the steps that data information is acquired; the initial condition, the generation boundary condition and the algorithm stability condition of a seismic wave propagation three-dimensional forward simulation model are determined, and high-order finite difference and numerical simulation are performed on the seismic wave propagation equation; a hybrid multi-core multi-node parallel forward simulation algorithm structure based on MPI/OpenMP is designed through combination of the processing capacity of the MPI for multi-node parallel and OpenMP for multi-core computing; and multi-gun data cyclic parallel computing is controlled by the MPI, and the multi-gun wave field slice result and the ground seismic record data are outputted to simulate and generate the exploration seismic wave field. The computing efficiency can be greatly enhanced and the computing accuracy can be effectively enhanced so that the requirements of three-dimensional seismic wave field generation for the computing efficiency and accuracy can be met.

The invention relates to a method and apparatus for determining an interval velocity under a seismic scale. The method includes the following steps that: an interval velocity under a logging frequency is obtained; a correlation coefficient in a rock physical statistic relation is determined according to the interval velocity under the logging frequency and a corresponding known quality factor; a first objective function is established according to the interval velocity under the logging frequency and the correlation coefficient in the rock physical statistic relation, and an interval velocity under the seismic scale, which satisfies a velocity dispersion relation, is obtained according to the first objective function; the length of a scale coarsening window at a current position is determined, the number of sampling points of the scale coarsening window at the current position is obtained through using the length of the scale coarsening window at the current position; and an interval velocity which has been subjected to seismic scale coarsening at the current position is determined according to the interval velocity under the seismic scale which satisfies the velocity dispersion relation and the number of the sampling points; and the interval velocity which has been subjected to seismic scale coarsening at the current position is corrected, so that the interval velocity under the seismic scale, which can accurately reflect the travel time information of seismic wave propagation can be obtained.