38 results about "Amplitude versus offset" patented technology

The invention provides a method for performing joint inversion on the P-wave and S-wave velocity ratio of a reservoir by utilizing P-wave and converted wave data. According to the method, an inversion target function is constructed by adopting a concept that a gamma change rate acquired from gather seismic reflection information and a gamma change rate acquired from travel time information are infinitely approximate, and key parameters of the target function comprise a P-wave intercept, a P-wave gradient, a converted wave gradient and the P-wave and S-wave velocity ratio calculated according to the travel time information, and can be acquired from the actually input amplitude versus offset (AVO) information of a P-wave and converted wave gather and the travel time information, so that the target function can be rationally constructed, and a finally inverted P-wave and S-wave velocity ratio elastic parameter is accurate.

The invention relates to a method for converting ladder diagram language into structure text language, which comprises the following steps of: storing the ladder diagram language into a storage structure beneficial to edition and conversion, and introducing virtual nodes at intersection points between vertical lines and other ladder diagram symbols which refer to real nodes; merging the virtual nodes to form an AOV (Amplitude Versus Offset) diagram; and converting the AOV diagram into a structure text by classifying different types of nodes according to the node sequence of the AOV diagram intopological sorting. The method has generality and can be used for accurately and effectively convert any complex ladder diagram into a structure text. Visual ladder diagram programming is realized in places where only structure text programming can be used formerly, so that user use is convenient, the threshold of PLC (Programmable Logic Controller) programming is reduced, and the programming efficiency of PLC is increased.

The invention belongs to the field of exploration geophysics, and particularly relates to a carbonatite oil and gas reservoir crack earthquake detection method. The method comprises the steps of: carrying out amplitude versus offset and azimuth angle analysis, speed versus offset and azimuth angle analysis, frequency versus offset and azimuth angle analysis respectively based on pre-stack seismic azimuth angle dataset, further carrying out ellipse fitting respectively to obtain a crack development azimuth angle, and predicting a crack development azimuth through a seismic attribute comprehensive analysis way; carrying out quality factor parameter extraction, anisotropic parameter inversion and non-hyperbolic moveout velocity analysis respectively based on pre-stack seismic trace dataset and shear wave velocity data, and predicting a reservoir crack development region by comprehensively utilizing the parameters above through a seismic attribute comprehensive analysis way. The carbonatite oil and gas reservoir crack earthquake detection method can give more comprehensive consideration to the geology of the reservoir and the physic characteristics of the globe, and the estimated crack azimuth and the predicted crack development region are more exact.

The invention discloses an inversion method of frequency dispersion amplitude versus offset (AVO). The inversion method comprises the following steps: acquiring a pre-stack trace gather; carrying out spherical diffusion compensation and dynamic correction on the pre-stack trace gather, and carrying out instant spectrum analysis on the pre-stack trace gather, so as to generate amplitude spectra under different frequencies; carrying out amplitude spectrum balancing on the amplitude spectra; acquiring a stacking velocity of sampling points in the pre-stack trace gather; generating a layer velocity of the sampling points according to the stacking velocity; generating speed variation rate of the velocity of vertical and horizontal waves under a set frequency and frequency dispersion degree of the sampling points according to the amplitude spectra after amplitude spectrum balancing, the layer velocity of the sampling points, and least square inversion; and ranking the generated frequency dispersion degree according to the trace gather serial number, so as to generate an attribute section of the frequency dispersion degree. By utilizing the inversion method of frequency dispersion AVO provided by the embodiment of the invention, the influence of a strong amplitude energy group caused by impedance difference of an elastic interface wave can be eliminated, and the false 'frequency abnormality' caused by the stacking when post-stack seismic data spectrum is analyzed can be avoided, so that the obtained result is more reliable.

The invention relates to a pre-stack non-linear fluid identification method for a fuzzy neural network of a chaotic quantum-behaved particle swarm. Fluid identification is always a key point and difficult point problem in the oil-gas exploration field. By aiming at deficiency in the common fluid identification method at present, a multi-attribute angle gather combination fluid identification factor is built by researching an AVO (amplitude versus offset) response characteristic comprising different fluids; a chaos search mechanism, a quantum-behaved particle swarm and a fuzzy system theory are organically combined to fully perform respective advantages and complementarities of the chaos search mechanism, the quantum-behaved particle swarm and the fuzzy system theory; a novel group intelligent optimization algorithm of a ''chaotic quantum-behaved particle swarm fuzzy system'' is developed and researched, and a mechanism and an optimizing performance of the pre-stack non-linear fluid identification method are researched from two aspects of the theory and practicality; problems of poor global search capability, premature convergence and the like in a traditional optimization algorithm are fundamentally improved; the optimization algorithm is introduced into fluid identification to form the pre-stack non-linear fluid identification method for the fuzzy neural network of the chaotic quantum-behaved particle swarm; the problem existing when a traditional fluid detection means is used for carrying out fluid identification is effectively solved; fluid identification precision is improved; and a new scientific and effect technical method is provided for the fluid identification.

The invention provides an AVO (amplitude versus offset) three-parameter inversion method based on particle swarm optimization, and belongs to the field of geophysical prospecting for petroleum. The method comprises the following steps: (1) pre-stack gather data d(theta) are input; (2) a longitudinal wave reflection coefficient Rpp is obtained, and an error function E between convolution of the longitudinal wave reflection coefficient Rpp and a wavelet w(theta) and the pre-stack gather data d(theta) serves as an objective function; (3) particle swarm optimization is used for looking for a longitudinal wave speed, a transverse wave speed and a density which allow a value of the objective function to be minimum, and the longitudinal wave speed, the transverse wave speed and the density are the three parameters. The method reduces the dependence on an original model, improves the inversion precision and has high anti-noise capacity.

The invention relates to a crack fluid type identifying method based on longitudinal wave frequency depending on amplitude versus offset (AVO) and azimuth. Earthquake anisotropism is related to frequency, and when crack media are filled with different kinds of fluid, difference exists between anisotropism intensity and the earthquake frequency changing gradient. According to the method, frequency information is introduced into an AVO and azimuth inversion theory of elastic media, and the inversion theory is expanded to the field of viscoelasticity, namely AVO and azimuth depending on frequency. By solving the formula of the AVO and azimuth depending on frequency, a longitudinal wave anisotropism frequency dispersion item is obtained. The method has the advantages that the application effect of practical data shows that longitudinal wave anisotropism frequency dispersion can be used for identifying the type of fluid in a crack, meanwhile, the method is good in water identifying effect, and the method can be used for practical data and can identify the type of fluid in a crack on an area where the anisotropism degree is high.

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.

The embodiment of the invention provides a method and a system for identifying oil and water in carbonate rocks. The method comprises the following steps of: acquiring a primary wave transmission signal of a seismic three-dimensional work area; carrying out pre-stack processing on the primary wave transmission signal; carrying out conventional seismic horizon calibration and explanation on seismic data obtained after carrying out pre-stack processing; carrying out inversion of a wave impedance on the seismic data obtained after carrying out pre-stack processing; according to the wave impedance and the AVO (Amplitude Versus Offset) effect of the seismic data, extracting a frequency corresponding to the seismic data; carrying out normalization processing on the seismic data corresponding to the frequency; and according to a result of the normalization processing, carrying out oil and water identification. Images can be simultaneously formed on a plane and a section; the method and the system are more convenient for the oil and water identification of a single well point and the statistic analysis of the geological rule on the plane; and the advantage of prediction before drilling of the method and the system is sufficiently played.

The invention provides an AVO (Amplitude Versus Offset) approximate formula based on an incidence angle and an attribute extraction method. The attribution extraction method comprises the following steps of: (1) proposing the AVO approximate formula based on the incidence angle; (2) carrying out theoretical derivation of the AVO approximate formula based on the incidence angle; (3) extracting the attributes of P, G and Rs by applying a conventional method; (4) uniformizing the attributes; (5) determining a b value through well data or an empirical formula of a study area, and then correcting the attributes extracted by the conventional method by applying a formula (14) and a formula (15); (6) comparing and animalizing a correction result and the well data, and correcting the correction result according to an analysis result to obtain a final attribute result. The invention has convenient and accurate calculation and small actual parameter error.

The invention discloses a method for analyzing oil gas information of the rock body by applying amplitude versus offset (AVO) large-angle trace gathers, which comprises the following the steps of: 1, processing denoising, dynamic correction, stretching and the like of data recorded by drift earthquake, recording reflection coefficients Rpp and incidence angles i, and acquiring a plurality groups of detection values corresponding to incidence angle i and the reflection coefficient Rpp; 2, constructing a sample set H (x, y) of all detection values of incidence angles i larger than 30, wherein the sample set in each sample, i and Rpp are the incidence angles and corresponding reflection coefficients Rpp obtained in the step 1; 3, fitting equation F by using the sample set H to obtain fitting values of R, W and V; and 4, calculating the obtained P, G and C by substituting the R, W and V obtained in the 2, and performing attributive analysis of the rock body oil gas information. According to the method, AVO of the incidence angle large-angle trace gathers is analyzed, theoretical error existing prior to Shuey equation fitting is eliminated, the obtained P, G and C are more accurate, and the oil information of the target rock body is more really reflected.

The invention relates to a residual phase correction method based on AVO (amplitude versus offset) abnormal type constraints. The residual phase correction method specifically comprises the following steps of (1) exciting earthquake waves, recording the earthquake waves of a working area, and generating an available CMP (common midpoint) or CRP (common reflection point) gather; (2) performing Fourier conversion on the inputted CMP or CRP gather; (3) performing PMO (phase moveout) correction on the processed CMP or CRP gather; (4) calculating and filtering the phases of the CMP or CRP gather after PMO processing; (5) performing frequency domain PMO correction on the CMP or CRP gather; (6) performing inverse Fourier conversion on the CMP or CRP gather after frequency domain PMO correction; (7) directly outputting the time domain CMP or CRP gather to obtain a time domain PMO gather; (8) applying the outputted time domain PMO gather to AVO analysis and explanation. The residual phase correction method is applied to oil gas detection.

The invention relates to the field of seismic data processing, and particularly relates to an attribute-based longitudinal wave data and converted wave data matching method and device. The method comprises the steps that a longitudinal wave channel set and a converted wave channel set of amplitude versus offset (AVO) of a target area are acquired; AVO inversion is performed on the longitudinal wave channel set so that the quasi transverse wave impedance attributes of longitudinal waves are acquired; superposition of the converted wave channel set is performed so that converted wave post-superposition data are acquired; the speed ratio meeting the preset conditions is acquired according to the quasi transverse wave impedance attributes and the converted wave post-superposition correlation; and the converted wave post-superposition data are transformed to a longitudinal wave time domain from a converted wave time domain according to the speed ratio so that the matched converted wave data are acquired. The quasi transverse wave impedance attributes and the converted wave data have higher correlation so that the precision of longitudinal wave and converted wave time matching can be enhanced, and the accurate basis can be provided to multi-wave seismic data joint inversion and interpretation.

The invention provides a two-phase medium amplitude versus offset (AVO) forward modeling method based on triple constraints. The two-phase medium AVO forward modeling method based on triple constraints comprises the following steps of: (1) calculating bulk modulus of a fluid saturation rock; (2) setting a pore flattening value; (3) calculating bulk modulus of a rock matrix, and constraining the bulk modulus by employing the first constraint; (4) calculating elastic parameters of a two-phase medium; (5) calculating two roots of an equation of Biot (1956), and constraining the roots by employing the second constraint; (6) calculating the speed of slow longitudinal waves, and constraining the speed by employing the third constraint; (7) calculating the bulk modulus of the rock matrix, and calculating the parameters of the two-phase medium; and (8) calculating reflection and transmission coefficients of a two-phase medium model. Therefore, the pore flattening of the rock serves as an object; constraint inversion is performed by employing the triple constraints; and the inversion precision and reliability are effectively improved.

The invention proposes a method for inversion of properties of a fracture. The method comprises: establishing an inversion objective function based on frequency-variant amplitude versus offset and azimuth (AVAZ) features; according to a calculation result of the inversion objective function, establishing a likelihood function of a fracture parameter; combining prior distribution of the fracture parameter with the likelihood function of the fracture parameter and calculating a posterior probability distribution function of the fracture parameter; and with a statistic method, displaying an inversion result visually. Compared with the existing method, the novel method has the following beneficial effects: the result of the novel method is close to the real situation in terms of medium hypothesis presupposition; more fracture properties are predicted in terms of results and fluid identification can be performed; and the effective and reasonable fusion process of balancing geology, logging,and seismic information is realized.

The present invention discloses an AVO retrieval method for a fractured medium, comprising: obtaining seismic data of the fractured medium, inverting the seismic data through a newly established AVO equation, and obtaining a reflection coefficient of the fractured medium. The present invention further provides an AVO retrieval device and equipment for the fractured medium. According to the invention, the AVO retrieval method, the device and the equipment for the fractured medium are capable of accurately inverting lithological characters of the fractured medium (namely surrounding rock medium+fracture).

The invention provides a hydrocarbon detection factor for detecting a coalbed methane enrichment and high permeability area and a method of using the hydrocarbon detection factor to detect the coalbed methane enrichment and high permeability area. The hydrocarbon detection factor AVO (Amplitude versus Offset) is characterized by difference between an intercept A and a gradient B (A-B), wherein (A-B) =2delta mu/(lambda+2mu)+1delta rho/2rho. The method comprises the steps of calculating intercepts and the gradients of earthquake return wave amplitude changed along with incident angle and the differences between the intercepts and the gradients (A-B) base on earthquake information; drawing hydrocarbon detection factor exception graphs with (A-B) serving as drawing data, the graphs comprising profile maps, planar graphs, horizon flattening graphs, space charts, and amplitude envelop diagrams; and determining the spacing position of the coalbed methane enrichment and high permeability area according to the graphs. The part with high exceptional strength of (A-B) is the part with high methane content and high permeability and can be judged as the coalbed methane enrichment and high permeability area.