46 results about "Synthetic seismogram" patented technology

A method for seismic characterization of subsurface Earth formations includes determining at least one of compressional velocity and shear velocity, and determining reservoir parameters of subsurface Earth formations, at least including density, from data obtained from a wellbore penetrating the formations. A quality factor for the subsurface formations is calculated from the velocity, the density and the water saturation. A synthetic seismogram is calculated from the calculated quality factor and from the velocity and density. The synthetic seismogram is compared to a seismic survey made in the vicinity of the wellbore. At least one parameter is adjusted. The synthetic seismogram is recalculated using the adjusted parameter, and the adjusting, recalculating and comparing are repeated until a difference between the synthetic seismogram and the seismic survey falls below a selected threshold.

The invention relates to a method and device for predicting the abundance of organic matters in a source rock. The method comprises the steps that a well logging curve of a target area is obtained; according to the well logging curve, a TOC value of the target area is calculated; according to the TOC value of the target area, well seismic calibration is carried out combined with the synthetic seismogram of the well logging curve; according to a result of the well seismic calibration, seismic attribution characteristics of the well bypass are extracted, and a relational expression between the TOC and seismic attribution characteristics is established; according to the relational expression, the spatial distribution of the target area TOC is established. The method for predicting the abundance of the organic matters in the source rock has the advantages that the distribution of high-porosity-and-permeability area of a source rock reservoir can be accurately identified and evaluated, andthe spatial position and physical property parameter distribution of the high-quality source rock reservoir are predicted.

The invention discloses a method for estimating the attenuation gradient of seismic waves based on variable mode decomposition. The method includes: calibrating a target layer by using logging, well logging and a synthetic seismogram; performing variable mode decomposition on seismic data on a trace by trace basis, and extracting the attenuation gradient of an intrinsic mode function in combination with the least squares algorithm, and making a weighted summation of the attenuation gradient of the intrinsic mode function and obtaining an attenuation gradient value of each earthquake trace; and determining the lithology of each target layer and hydrocarbons properties by using seismic attenuation gradient features. The method can be more effectively applied to attenuation gradient estimation of seismic signals with low signal to noise ratio and large frequency spectrum fluctuation. Therefore, the method can increase effectiveness of absorption attenuation gradient in indicating oil gas and is accurate in identifying lithology and hydrocarbons properties.

The invention discloses a production method for a prestack depth domain synthetic seismogram and relates to a petroleum seismic exploration forward numerical simulation technology. The production method comprises the following steps: firstly, converting depth domain seismic data into constant velocity depth domain seismic data by using a longitudinal wave velocity field; secondly, extracting depth domain seismic wavelets from the constant velocity depth domain seismic data; thirdly, transforming constant velocity depth domain seismic wavelets into a depth domain by using a longitudinal wave velocity model to obtain one group of depth domain seismic wavelet set matched with different depth stratal velocities, weighting the depth domain seismic wavelets by using a depth domain AVO (Amplitude Versus Offset) reflection coefficient, and then stacking to obtain a prestack depth domain synthetic seismogram angle gather. According to the technology, the problem that a depth domain convolution model cannot meet an algorithm with linear time invariant conditions is solved; the production method can be used as a basis for direction deduce analysis of depth domain seismic data and inversion of prestack depth domain parameters.

An embodiment of the invention provides an imaging method and device based on an optional wide angle wave equation. The method includes acquiring an established speed model and a determined source wave field; utilizing forward simulation to acquire a synthetic seismogram of the speed model; performing the inclination filtering process on the synthetic seismogram of the forward simulation and the determined source wave field; analyzing imaging accuracy of an optional wide-angle wave equation according to dispersion relation, and obtaining an optimal reference speed of the optional wide-angle wave equation; figuring out the optional wide-angle wave equation of the optimal reference speed by the finite difference method; performing migration imaging by adopting correlation imaging conditions to improve migration imaging accuracy of the optional wide-angle wave equation. Evanescent wave imaging noises of optional wide-angle wave equation prestack depth migration can be suppressed effectively, and imaging quality is improved; according to a reference speed optimization method, the imaging accuracy of the optional wide-angle wave equation prestack depth migration, so that stratigraphic with steeper dip angle can be imaged.

The invention relates to a two-dimension superposed seismic data amplitude compensation method and device. The method comprises the steps that time-domain seismic wavelets and a seismic effective frequency band range are extracted from two-dimension superposed seismic data, and time-domain well drilling reflection coefficients of a seismic data amplitude weakening area are determined; convolution is conducted on the time-domain seismic wavelets and the time-domain well drilling reflection coefficients, and a time-domain well drilling synthetic seismogram channel is obtained; a time-domain well side seismic channel in the two-dimension superposed seismic data is transformed to obtain well side seismic channel amplitude spectrums, and the time-domain well drilling synthetic seismogram channel is transformed to obtain well drilling synthetic seismogram channel amplitude spectrums; the well side seismic channel amplitude spectrums and the well drilling synthetic seismogram channel amplitude spectrums are used for obtaining amplitude compensation factors within the seismic effective frequency band range; the boundary of the amplitude weakening area in the two-dimension superposed seismic data is obtained; amplitude compensation is conducted on the two-dimension superposed seismic data through the amplitude compensation factors within the seismic effective frequency band range and the boundary of the amplitude weakening area in the two-dimension superposed seismic data.

The invention provides a synthetic seismogram method and a synthetic seismogram device, and relates to the field of seismic exploration. The method comprises the following steps: getting the stratum model, seismic wave frequency and seismic wavelet of a target work area, wherein the stratum model includes at least one type of interface, and there is at least one interface of each type; calculating the reflection coefficient of each stratum according to the stratum model and the seismic wave frequency, and getting a reflection coefficient matrix containing frequency-dependent reflection coefficients; calculating the synthetic seismogram spectrum of each moment according to the reflection coefficient matrix and the seismic wavelet; and carrying out Fourier inverse transform on the synthetic seismogram spectrum to get a synthetic seismogram of all moments. Both a conventional wave impedance interface of which the media on both sides are homogeneous isotropic media and a special interface of which the media on both sides are homogeneous anisotropic media can be calculated. A synthetic seismogram method applicable to unconventional oil and gas reservoirs such as thin or viscoelastic reservoirs is provided. A geological assurance is provided for accurate exploration and efficient development of oil and gas resources.

The invention belongs to the field of seismic wave information processing technologies, and particularly relates to a surface wave separation method and a surface wave separation system based on morphological component analysis. The surface wave separation method based on morphological component analysis comprises the steps of: step a, making a synthetic seismogram, and constructing a surface wave separation model based on planar dictionary morphological component analysis; step b, selecting a planar non-sampling wavelet dictionary for carrying out sparse representation on surface wave signal components, and selecting a planar local discrete cosine dictionary for carrying out sparse representation on reflected wave signal components; step c, and adopting morphological component analysis under a planar dictionary for separating the surface wave signal components and the reflected wave signal components. The surface wave separation method and the surface wave separation system take both surface wave signal characteristics and reflected wave signal characteristics into account, can separate the surface wave signals and the reflected wave signals more effectively, fully utilize correlation between channels, and make the separation effect of surface wave signals better while considering that the surface wave signals are concentrated in a low-frequency high wavenumber domain under the planar non-sampling wavelet dictionary.

The invention provides a fluvial facies low-sand-factor reservoir prediction method. The method includes the following steps that: 1, synthetic seismogram fine calibration is performed so as to clarify the depth range of a fluvial facies low-sand-factor reservoir; 2, a variety of attributes are extracted, the macroscopic distribution characteristics of the main body of a river channel are jointlyanalyzed; 3, rock electric analysis is performed so as to optimally select a reservoir indication sensitivity curve; and 4, inversion is performed by using the sensitivity curve, the distribution condition of the reservoir in a longitudinal direction is predicted. According to the fluvial facies low-sand-factor reservoir prediction method of the invention, based on geophysics means and rock electric analysis, a practical and effective identification method is established. With the method adopted, the distribution of the fluvial facies low-sand-factor reservoir can be determined accurately; a potential target region can be revealed; and oil and gas exploration can better guided. The method can provide guidance and reference for other sand body reservoir prediction.

The invention relates to a wavelet sidelobe information-based oil reservoir identification method, and belongs to the technical field of petroleum exploration and development. The method generates a synthetic seismogram through logging data and theoretical wavelet convolution, determines a relation between depth and time, and then calculates to generate a certainty wavelet; and establishes three wave impedance models of an oil layer, a water layer and anon-reservoir layer, generates a reflection waveform of forward modeling with certainty wavelet convolution, compares and analyzes an amplitude difference situation of three reflected wave events near an oil reservoir, and determines the reflected wave with the maximum amplitude change percentage of the reflected wave event, and the amplitude of the reflected wave event is formed due to a sidelobe effect of reflected waves of a top interface of the oil reservoir; and the event that reflects oil reservoir reflected wave sidelobe information is tracked in seismic data, a seismic amplitude value is extracted along a seismic interpretation layer, and an area with relatively strong amplitude is selected as an identified oil reservoir area. The wavelet sidelobe information-based oil reservoir identification method provided by the invention is simple and practical, and can accurately identify an oil reservoir whose wave impedance of upper and lower strata has large difference.

The invention provides a fluvial facies log facies rapid interpretation method and a fluvial facies three-dimensional sedimentary facies model deterministic modeling method. The fluvial facies three-dimensional sedimentary facies model deterministic modeling method comprises the steps of based on single layer interpretation data of each well, firstly performing log facies identification by using thickness and oil bearing property data and then performing log facies rapid correction based on the shape, amplitude and top/bottom contact relations of a natural gamma or natural potential curve of each single layer; by using the synthetic seismogram calibration technology, determining the seismic horizon corresponding to each single layer and extracting the corresponding root mean square attributes in a certain time window of the seismic horizons; by using the obtained log facies of each single layer and the corresponding root mean square attribute of each single layer, drawing a fluvial facies sedimentary facies map; inputting the sedimentary facies boundaries of fluvial facies river channels in the digital sedimentary facies map into geologic modeling software and establishing a three-dimensional sedimentary facies model by directly using the assignment method. The log facies interpretation is more efficient and rapid and sedimentary facies maps are more accurate; nondeterminacy of sedimentary facies models caused by random modeling is prevented; sedimentary facies models established by using the method can be used for constraining three-dimensional geologic model modeling such as porosity and permeability.

The invention provides a shale gas geological sweet spot prediction method comprising the following successive steps: step one, a synthetic seismogram is acquired based on an organic carbon content logging curve; step two, well-to-seismic correlation is performed on the synthetic seismogram and the actual seismic data, and the actual seismic data are constrained by the synthetic seismogram to perform inversion so as to acquire inversion data volume; and step three, geological sweet spot prediction is performed according to the inversion data volume obtained in the step two. The method has the advantages of instrument measurement, acquisition of detailed information of organic matter abundance of shale gas in the well and high resolution and utilizes the advantage of large transverse density of the seismic data prediction technology so that the high-resolution inversion result can be obtained under the condition of a small amount of drilling in the early exploration or a lot of drilling in the development phase.

The invention provides a seismic identification method for complex fault block unconformity surfaces, comprising the following steps: S1, acquiring the initial time depth and structure features of a simple area, and grasping the structure initial form and features of the whole research area by constructing the structure features of the simple area; S2, for construction of a complex area, performing complex area fine synthetic seismogram calibration, and determining the time depth relationship and seismic reflection features of an unconformity surface; and S3, extrapolating a well-free area through connected well profile interpretation, and performing tracking interpretation of the unconformity surface of the complex area. The seismic identification method for complex fault block unconformity surfaces provides a foundation reference for residual oil distribution rule research and reserve calculation of the oil reservoirs in complex fault blocks, plays a guidance role in later development of oil reservoirs of the kind, has a broad popularization and application prospect and can bring remarkable economic and social benefits.

The invention discloses a forward simulation method for a sand-mud interbed CO2 geology sealing time-shifting earthquake without shear wave velocity logging. The method comprises the following steps: collecting data; extracting the data layer by layer; using logging information to calculate a sandstone mineral composition curve, calibrating the longitudinal and shear wave velocity under the pressure condition after the CO2 injection, and forecasting the shear wave velocity; executing the mixed fluid to replace the longitudinal and shear wave velocity curve after the injection; reserving the logging information time-depth conversion of the thin-layer information and using a Zoeppritz equation to calculate the reflection coefficient; executing the convolution with Ricker wavelet to obtain a synthetic seismogram; and using the time-shifting forward artificial synthetic seismogram of the different injection stages and different basic frequencies before and after the CO2 injection to subtract, to obtain the difference forward earthquake response. The method is capable of, in allusion to the feature of the complicated sand-mud thin interbed, solving the mixed fluid saturation replacement problem of the different reservoir features in the CO2 oil flooding and geology sealing process better and forecasting the longitudinal and shear wave velocities of the pressure change in the CO2 injection stage.

The invention provides a self-adaption curvelet threshold value earthquake denoising method based on local variance analysis. According to the method, on the basis that deep analysis is conducted on the characteristics of a curvelet coefficient on different scales and at different angles, a self-adaption threshold value technology is provided so that effective separation of a signal and noise can be achieved at any angle, protection conducted on non-noise components is enhanced with the help of local variance information of a curvelet area, and therefore damage to the effective signal especially the weak signal can be reduced. Practices on synthetic seismogram and land seismic data prove that the actual denoising effect of a threshold value iteration method is not ideal, the denoising effect of the method is more real and effective, and the method has the unique advantages in the aspects of noise attenuation and detail protection.

The invention provides a logging and seismic velocity matching method based on seismic rock physical experiment analysis. The method comprises the following steps of step1, through seismic frequency band rock physical experiment analysis, establishing a changing curve of a velocity versus a frequency, which is a velocity dispersion variation law; step2, constructing a rock physical model suitable for representing a seismic frequency band dispersion characteristic; step3, using a rock physical model modulus calculation formula to carry out point-by-point mapping dispersion correction of an acoustic wave curve; and step4, carrying out synthetic record calibration on the acoustic wave curve after dispersion correction, and comparing and analyzing a seismic well bypass and a synthetic seismogram, and outputting correction curve results of all depths of an entire acoustic wave logging curve. By using the method, a matching problem between a seismic velocity and a logging velocity on a scale is eliminated, and a velocity dispersion problem caused by a large difference between the two on a frequency band is corrected; and the method has clear physical connotation and a rock physics basis, and accuracy of well-seismic matching and calibration is greatly icnreased.

The invention discloses a three-dimensional fault-dissolved body model making method. The core of the method is that only a specific waveform selected by a user can be modeled in a synthetic seismogram. The method comprises the following steps: firstly, the speed, the thickness and the scale of each geologic body of the fault-dissolved body are acquired and counted; a fault-dissolved body two-dimensional plane speed model is then drawn; equidistant drawing of several two-dimensional plane speed models is completed; a control point is found out on the two-dimensional plane; a ray is built fromthe point, and a mapping relationship with a next profile is built; and by using the same method, the same mapping with the next plane is built, the blank part between the planes is filled by using aspline interpolation method, so that the three-dimensional model is formed. The description of the internal and external structures of the fault-dissolved body is greatly improved, and accuracy of precise description of the fault-dissolved body is improved.

The invention relates to a reservoir prediction method and device based on a synthetic seismogram, and belongs to the technical field of petroleum exploration development. A density-speed relationshipempirical formula suitable for a research area is searched to carry out the environment correction of a mudstone collapse section on well logging data in the research area to obtain a corrected density well logging curve and acoustic logging curve, according to the corrected density well logging curve, a synthetic seismogram record is manufactured to obtain a synthetic record which is more matched with a well byway, so that important basic data is provided for lowering multiplicity and improving inversion accuracy for subsequent model inversion, and therefore, reservoir predication accuracy is further improved.

The invention discloses a method of recognizing a tiny erosion groove in a raised region, and belongs to the field of geological engineering. The method includes the steps of selecting a standard well for each of drilled wells inside and outside a large erosion groove in a raised region, and obtaining logging information of the standard wells; establishing interval velocity models for the inside and outside of the large erosion groove respectively according the logging information; combining the logging information and three-dimensional seismic data to obtain an initial synthetic seismogram, and conducting a calibration analysis of the initial synthetic seismogram using the interval velocity models to obtain a final synthetic seismogram; recognizing the top boundary velocity and bottom boundary plane of uncomformity velocity of the inside and outside of the large erosion groove according to the final synthetic seismogram so as to trace seismic reflecting boundary events of the top boundary and bottom boundary plane of uncomformity of the inside and outside of the large erosion groove in the raised region isochronally, and connecting the events of the same time to form a seismic data volume; and slicing the seismic data volume isochronally by using the stratigraphic slice technology and recognizing a tiny erosion groove.

The method includes steps: (1) through analysis of collected prestacked seismic data gives out seismological record of actual measured angle track set; (2) setting up geologic model; (3) selecting convergent function and determining precision of inversion; (4) determining search range and interval of model parameters, and integral encoding parameters, generating total body of initial stochastic model for fitting geologic model; (5) calculating synthetic seismogram of total body, comparing synthetic seismogram with seismological record actual measured, and calculating value of objective function; (6) calculating GA generates new total body of mode P[j] to update initial total body; (7) calculating synthetic seismogram Syn[j] of P[j] , comparing Syn[j] with Seis, and calculating and saving value of objective function; (8) ending steps and outputting result if termination condition is met; otherwise repeating (6)-(8). The method raises resolution of inversion without constraint condition of well.

The invention discloses a seismic instantaneous attribute extraction method based on a phase space filtering strategy. In a wavelet transformation domain, an area of the effective signal energy distribution is adaptively determined. Based on that, a noised-signal instantaneous attribute analysis method is provided by using a relation of wavelet transformation and Hilbert transformation. In the invention, a quantitative index of measuring instantaneous-attribute anti-noise performance is provided; through calculating instantaneous attributes of a synthetic seismogram of different signal to noise ratios, anti-noise performance of different methods is contrasted. A calculating result of the method in the invention possesses good anti-noise performance and precision. The method is applied to real data so that a reservoir characteristic can be clearly depicted.

A method for establishing an initial geological model based on multiple layers and multiple wells, comprising the following steps: for each well in the work area, for each formation of the well, make a synthetic seismic record, perform horizon calibration, and obtain seismic traces beside the well ; For each well in the work area, for each formation of the well, obtain the stratum conversion factor between the seismic record at the formation place of the well and the seismic trace beside the well; for each well in the work area , for each formation of the well, calculate the correlation coefficient between the seismic record at the desired position in the work area and the seismic record at the logging position; for each well in the work area, for each formation of the well , calculating the weight of the correlation coefficient of the formation for the well. This method can establish an initial geological model that is accurate and can meet the needs of the actual work area in the case of complex strata in the work area.