130 results about "Seismic processing" patented technology

This invention relates to mapping the hydrocarbon reservoir characteristics by mapping the reservoir formations that display dynamic elastic nonlinearity responses to the seismic signals. The main reason of this nonlinear behavior in the reservoir rocks is their bulk rock property: the porosity, fractures, differential pressure and pore saturation. To map these bulk rock properties, the interaction of the two seismic waves as they propagate through elastically nonlinear rocks is recorded. Two compressional seismic signals are transmitted from the surface. Seismic reflection data using surface or borehole detectors are recorded. One of the transmitted signals is a conventional swept frequency and the other is a mono-frequency signal. During the propagation of these two signals through the elastically nonlinear reservoir rocks, there is an interaction between the two signals. The sum and difference frequencies of the two primary seismic signals that were transmitted from the surface are created. These new frequencies constitute an "interaction' wave that travels along with the two primary waves. In this invention, the "interaction' signal created by the two seismic waves as they propagate through the reservoir rocks is separated from the primary signals and used to map the reservoir rocks that exhibit elastic nonlinearity due their bulk rock properties. The cross-correlation of the recorded data with the swept frequency signal provides a conventional seismic data set that is used for normal 2-D or 3-D seismic processing. The cross-correlation of the recorded data with the summed and differenced signals provides two sets of data that represent the seismic reflected image from the subsurface nonlinear formations.

A method of constructing a basis of functions intended for the building of approximations of one-way or two-way seismic traveltime versus offset functions. The method is characterized by the combination of the following steps of (a) creating a distribution of reference one-way or two-way traveltime versus offset functions by traveltime modelling in a set of velocity models representing possible velocity distributions, (b) obtaining new reference functions by modifying these reference traveltime functions by applying an operator to them, (c) selecting a set of discrete offsets to make these new reference functions discrete, (d) arranging these discrete functions in columns to form a matrix, (e) applying a singular value decomposition to this matrix, with singular values sorted in decreasing order, to express its columns as linear combinations of the columns of an orthogonal matrix, and (f) building the basis functions by interpolating the columns of the orthogonal matrix.

There is provided herein a New system arid method of local attribute match filtering which operates in the local attribute domain via the use of complex wavelet transform technology. This approach is adaptable to address various noise types in seismic data and, more particularly, is well suited to reduce the noise in geophone data as long as an associated hydrophone signal is relatively noise-free.

The optimized design method of geological geophysical model based three-dimensional seismological observation system includes the following steps: A). creating geological geophysical model; B). designing two kinds of several kinds of observation systems with three-dimentional geological data acquisition; C). adopting imaginary spectrum method and combinatino of three-dimensional wave equation numerical analog and three-dimensional geophysical model analog two methods of implement data acquisitino work; D). using common-reflection point as basis, making depth deviation treatment of acquired data before superposition to obtain several kinds of imaging results of seismic treatment; and E). making comprehensive comparison and evaluation of imaging quality of said imaging results and defining one optimum seismic imaging result. The invention is extensive in application range, can obtain good effect for making seismic exploration of petroleum and natural gas.

According to a preferred aspect of the instant invention, there is provided herein a system and method for improving the computational efficiency of the DMO transformation that has many uses in the seismic processing arts. More particularly, the instant inventor has conceived and invented a faster method of calculating a log-stretch DMO transformation that utilizes multiple independent time windows, each with its own starting and ending time. A particularly preferred usage of the improved DMO method is as an element of a multiple attenuation program such as SRME.

A method of assessing acquisition errors in seismic images in a seismic data volume. The method includes selecting a seismic attribute in a seismic data volume and then stacking seismic quality image measurements taken along the selected attribute. The stacked measurements are then related on the basis of any vertical correlation and any vertically correlated feature is identified as a cobweb. Any identified cobwebs are removed from the seismic data volume.

A method for identification and prediction of a fore-land basin extremely-thick conglomerate body belongs to the technical filed of petroleum and natural gas exploration and development. The method comprises the following steps: the step 1) determining electrical characteristics of a gravel layer; the step 2) determining the characteristics of gravel layer seismic horizon and seismic facies; the steps 3) carrying out electrical profile and earthquake depth profile superposition; and the step 4) carrying out gravel layer lithology and lithofacies space identification. The beneficial effects of the method are that gravel layer distribution range, lithology and lithofacies vertical and horizontal distribution rules and the like, which restrict fore-land basin oil and gas exploration and development at each geological time in the fore-land basin can be determined; speed traps caused by the gravel layers can be eliminated to the maximum degree; the earthquake processing imaging speed is allowed to be more accurate; seismic data quality reaches a new level; entrapment implement precision is improved greatly; and well exploration success rate can be further improved.

A method and visualization apparatus for spectral analysis of time-and-space varying signals enables high resolution investigation of 3D seismic data for the exploration of oil and gas. The method extrapolates multi-resolution short windows into an average long window then computes its FFT. Extrapolation uses the continuity relationship between data inside and outside of short windows. Applications of the method are illustrated with graphical screen 3D volume displays of amplitude spectra, dip and azimuth, curvature and faults (figure below). Aside from high resolution these displays improve the productivity of a seismic interpreter.

The invention discloses a method for extracting a converted wave angle channel set for improving the speed and precision of calculating the converted wave incidence angle in the earthquake process. A channel set, the converted wave speed and aeolotropy parameters of a converted wave are utilized for calculating the speed, the aeolotropy parameters of a longitudinal wave, the longitudinal shot-geophone distance corresponding to the converted wave shot-geophone distance, the converted wave travel time of the aero shot-geophone distance, the longitudinal wave travel time and the interlayer longitudinal wave speed, wherein the channel set is formed through longitudinal wave incidence converted wave data and transverse wave reflection converted wave data, the amplitude of the channel set changes along with the offset distance, and the normal difference of the channel set is corrected. The converted wave incidence angle theta is calculated according to the longitudinal wave time difference equation and the interlayer longitudinal wave speed, and the incidence angle of each sampling point is calculated, wherein each sampling point is placed on the angle channel of the incidence angle. The process is carried out repeatedly for all sampling points to obtain the converted wave angle channel set. According to the method, the calculation is easy to conduct, and the speed and precision of extracting the converted wave angle channel set can be improved.

Implementations of various technologies for processing seismic data. In one implementation, the seismic data may be processed by creating a fictitious source-receiver line connecting a source with a receiver location of interest, projecting one or more receiver locations adjacent the receiver location of interest onto the fictitious source-receiver line and decomposing seismic data on the receiver locations disposed on the fictitious source-receiver line into up-going wavefields and down-going wavefields.

Seismic processing method, in which, in order to eliminate multiple reflections on seismic data, seismic data are migrated in time or in depth (110) arid the data thus migrated are processed to determine an approximation of multiple reflections to be subtracted from, seismic data (120 to 160).