WO1991015783A1 - Enhanced detection of seismic diffractor targets - Google Patents
Enhanced detection of seismic diffractor targets Download PDFInfo
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- WO1991015783A1 WO1991015783A1 PCT/US1990/001772 US9001772W WO9115783A1 WO 1991015783 A1 WO1991015783 A1 WO 1991015783A1 US 9001772 W US9001772 W US 9001772W WO 9115783 A1 WO9115783 A1 WO 9115783A1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
- G01V1/003—Seismic data acquisition in general, e.g. survey design
Definitions
- the present invention relates generally to the field of geophysical measurement systems. More particularly, the present invention provides a novel method by which seismic exploration data can be collected and analyzed to selectively enhance the detection of diffractor targets to portray diffraction patterns in seismogram displays.
- the latter category of geological contrasts includes: 1) fault- displaced interfaces between dissimilar sedimentary rock layers; 2) the edges of isolated lens-like geological deposits or formations; 3) the edges of a rock layer whose thickness changes with lateral distance to form a "pinch out;” 4) zones of a porous rock formation in which pore fluids having contrasting acoustic parameters have accumulated or have been trapped by bounding rock materials of low porosity to form edges or boundaries of contrasting elastic parameters (principally as a result of the differences in pore fluids); and 5) the edges of fractures and fault interfaces in otherwise homogeneous geological rock formations at which, for example, shear waves are predominandy reflected.
- Seismic reflections from localized contrasts in geologic structures produce anomalous patterns in the seismograms which are referred to as "diffraction" patterns. These patterns are associated with the boundary edges of discontinuities in elastic parameters within or between the geological materials comprising the medium. The positions and shapes of these patterns in the seismogram display are indirectly related to the location and geometry of the boundaries by which they are produced.
- diffractors Boundaries in geological formations which produce such diffraction patterns in seismograms are often referred to as "diffractors.” Localized anomalies in homogeneous rock materials, such as a brine-filled cavity perched in an anhydrous salt dome formation, a small solution cave in limestone, a man-made tunnel in hard rock, and other small high- contrast anomalies are also often referred to as diffractors. Diffraction patterns in seismogram displays, although they are physically related to the geometrical structure of a geological formation, do not delineate actual structure interfaces or boundaries between contrasting materials but, instead, are an ancillary part of the elastic wave propagation and reflection phenomena associated with such boundaries.
- a man-made tunnel or a solution cave is wholly derived from the interpretation of the presence and orientation and position of such cavities as "diffractor" targets of interest.
- a bounded-volume zone of oil and/or gas trapped in a geological formation will exhibit elastic wave contrasts with the surrounding geological materials and, therefore, its size and spatial distribution may be interpreted in terms of its edge boundaries.
- the method 1 3 provides information on the relative average velocity along each of the wave 1 4 propagation ray paths between all of the diffractor targets portrayed in the 15 seismogram and the detectors which receive their reflections.
- FIG. la is an illustration of seismic reflection paths for a small, localized
- FIG. lb is an illustration of seismic reflection paths for a small, localized
- FIG. 2b is an illustration of the cavity target reflection seismograms
- FIG. 3 is an illustration of the "shoot-through" seismic survey field method 1 2 wherein multiple seismograms are obtained by sequentially operating the seismic 1 3 source at each detector location in the survey array layout.
- FIG. 4a is an illustration of an ensemble of overlaid seismogram patterns
- FIG. 4b is an illustration of an ensemble of overlaid seismogram patterns 8 obtained by utilizing the shoot-through seismic field method with the irregular 9 detector array in a inhomogeneous geologic medium illustrated in FIG. lb.
- I I gathering and stacking method that depend upon systematic adjustments in source- 1 2 to-detector signal travel times to account for the wave propagation ray path 1 3 geometries and velocity structure of the medium will not be effective. That is, to be 1 4 productive, seismic reflection event time adjustments in the recorded detector signal 1 5 records must be preserved and adjusted in accuracy to within less than one 1 6 millisecond for seismic signals in the 400-1600 Hz frequency range. Therefore, in 17 contrast with conventional data processing techniques developed for lower 1 8 frequency seismic signals, the small but random time variations caused by the
- the present invention provides a novel method for processing data relating
- FIGS, la and lb illustrate these two application conditions and the reflection event two-way signals and their travel times.
- t,j 2 the two way time for a reflection signal to travel from the source to the detector at location 2
- R 1 .R 2 the ray path distances for downgoing and upgoing seismic waves, respectively
- v the velocity of the elastic wave signal in the geologic medium.
- the travel times of the reflection events along each target-to-detector path are governed by a different propagation velocity because of inhomogeneities along the different ray paths.
- the general equation for the time required for a signal to travel from the source, s, at location no. 1 to any of the detectors, d n is given by the following equation: Similar equations can be constructed to calculate the respective travel times from source to detector for the cases in which the source is positioned at other locations.
- FIGS. 2a and 2b illustrate the form of the example cavity target reflection seismograms that would be obtained in the ideal and practical cases illustrated in FIGS, la and lb, respectively.
- the cavity target will produce a hyperbola pattern in the seismogram display which is characteristic of the localized diffractor target and the geometry of each ray path.
- the reflection time shifts caused by the known or assumed ray path geometries and the velocity structure in the geologic formation are computed so as to flatten the hyperbolic curvature such that each detector output signal trace may be summed (gathered) to yield an enhanced reflection wavelet.
- the hyperbolic pattern becomes badly distorted because of the combined effects of irregular (known) detector elevations and unknown propagation velocities along each ray path, thereby prohibiting the computation of the necessary time shifts needed for alignment and summation of the signals.
- FIGS. 4a and 4b illustrate simplified representations of ensembles of overlaid seismogram patterns obtained from the shoot-through data acquisition process for the ideal and practical cases of FIGS, la and lb, respectively. These two-dimensional seismogram patterns are identical in shape to the seismograms shown in FIGS.
- a two-dimensional cross correlation analysis may be applied to determine the relative time offsets among the patterns and, as a byproduct, yield the individual relative average wave propagation velocity along each ray path.
- the patterns can then be time aligned and summed to produce an enhanced pattern.
- the enhancement gain of this processing technique may be exceptionally high. In the examples shown in FIGS.
- the enhancement gain factor for diffractor targets will be approximately equal to the square root of the number of source positions.
- the important aspects of this new concept are: (1) It is specialized to localized reflector targets such as a cylindrical cavity but is generally applicable to many forms of diffractor targets; (2) only those reflection rays traveling the same paths are combined in the pattern enhancement process and, therefore, there is no need for geometrical or velocity corrections in the travel times prior to applying the seismogram pattern enhancement process; (3) the two-dimensional pattern enhancement process provides diffractor target detection enhancement in a manner essentially independent of the inhomogeneous characteristics of the geologic medium.
- the enhancement method of this invention is sufficiently general to be equally applicable to reflections which are observed in three dimensions. That is, the illustrations used earlier to describe the method depicted a reflection target located directly under the survey line and, hence, in the vertical plane containing the detector array.
- the diffractor target need not be constrained to this two-dimensional survey layout orientation for the enhancement method to be applicable.
- the target may be laterally located away from the vertical plane of the detector array to comprise a three- dimensional source-target-detector orientation.
Abstract
A method by which seismic exploration data are collected (2-49) in the field and analyzed to selectively emphasize and enhance the detection of diffraction targets and the portrayal of diffraction patterns in the seismogram displays. The method of the present invention has the advantage of discriminating against any seismic reflections which do not originate from geological structures that produce diffraction patterns in the seismogram display. This method has additional advantages associated with its ability to determine the elastic wave velocities in the geologic materials comprising the formations through which the elastic waves are transmitted and detected. In particular, the method provides information on the relative average velocity along each of the wave propagation ray paths between all of the diffractor targets portrayed in the seismogram and the detectors which receive their reflections.
Description
Enhanced Detection of Seismic Diffractor Targets
Statement of Governmental Interest The United States Government has rights in the present invention pursuant to Contract DACA39-87-K-0063. The United States Government has a nonexclusive, nontransferable, irrevocable, paid up license to practice or have practiced on behalf of the United States, this invention throughout the world.
Field of the Invention The present invention relates generally to the field of geophysical measurement systems. More particularly, the present invention provides a novel method by which seismic exploration data can be collected and analyzed to selectively enhance the detection of diffractor targets to portray diffraction patterns in seismogram displays.
Background Seismic geophysical exploration surveys and associated data processing techniques are required in special cases to detect reflections from small localized reflection targets such as caves and underground cavities or to depict the boundary edges between two or more geological materials or structures having contrasting elastic parameters. The latter category of geological contrasts includes: 1) fault- displaced interfaces between dissimilar sedimentary rock layers; 2) the edges of
isolated lens-like geological deposits or formations; 3) the edges of a rock layer whose thickness changes with lateral distance to form a "pinch out;" 4) zones of a porous rock formation in which pore fluids having contrasting acoustic parameters have accumulated or have been trapped by bounding rock materials of low porosity to form edges or boundaries of contrasting elastic parameters (principally as a result of the differences in pore fluids); and 5) the edges of fractures and fault interfaces in otherwise homogeneous geological rock formations at which, for example, shear waves are predominandy reflected. Seismic reflections from localized contrasts in geologic structures, such as those described above, produce anomalous patterns in the seismograms which are referred to as "diffraction" patterns. These patterns are associated with the boundary edges of discontinuities in elastic parameters within or between the geological materials comprising the medium. The positions and shapes of these patterns in the seismogram display are indirectly related to the location and geometry of the boundaries by which they are produced. Boundaries in geological formations which produce such diffraction patterns in seismograms are often referred to as "diffractors." Localized anomalies in homogeneous rock materials, such as a brine-filled cavity perched in an anhydrous salt dome formation, a small solution cave in limestone, a man-made tunnel in hard rock, and other small high- contrast anomalies are also often referred to as diffractors. Diffraction patterns in seismogram displays, although they are physically related to the geometrical structure of a geological formation, do not delineate actual structure interfaces or boundaries between contrasting materials but, instead, are an ancillary part of the elastic wave propagation and reflection phenomena associated with such boundaries. Since these diffraction patterns do not correspond to geometrical images of the structures which produce them, many seismic data processing techniques have been developed and used to either suppress or
reconstitute the diffraction pattern information into a more accurate seismogram so that the image presented is a better representation of the true structural geometry of the formation. The resulting seismogram patterns are then interpreted to infer the geophysical and geological characteristics portrayed for purposes of identifying the presence of oil, gas, or other minerals, or to determine geotechnical information which is useful in underground construction or of other engineering importance. In many cases, the most important information interpreted from such seismograms is related to the discrete edges and boundaries between the contrasting geologic materials. For example, detection and location of a man-made tunnel or a solution cave is wholly derived from the interpretation of the presence and orientation and position of such cavities as "diffractor" targets of interest. Similarly, a bounded-volume zone of oil and/or gas trapped in a geological formation will exhibit elastic wave contrasts with the surrounding geological materials and, therefore, its size and spatial distribution may be interpreted in terms of its edge boundaries.
1 Summary of
2 the Invention
3 The present invention pertains to a novel concept and method by which
4 seismic exploration data are collected in the field and analyzed to selectively
5 emphasize and enhance the detection of diffraction targets and the portrayal of
6 diffraction patterns in the seismogram displays. For applications in which
7 diffractor targets are of primary interest, this method has the advantage of
8 discriminating against any seismic reflections which do not originate from
9 geological structures that produce diffraction patterns in the seismogram display.
I 0 This method has additional advantages associated with its ability to determine the
I I elastic wave velocities in the geologic materials comprising the formations through 1 2 which the elastic waves are transmitted and detected. In particular, the method 1 3 provides information on the relative average velocity along each of the wave 1 4 propagation ray paths between all of the diffractor targets portrayed in the 15 seismogram and the detectors which receive their reflections.
1 6 These and other objects, features and advantages of the invention will
1 7 become more readily apparent from the following detailed description of the 1 8 preferred embodiment when read in conjunction with the drawings.
1 Brief Description
2 of the Drawings
3 FIG. la is an illustration of seismic reflection paths for a small, localized
4 target for an idealized detector array in a homogeneous geologic medium.
5 FIG. lb is an illustration of seismic reflection paths for a small, localized
6 target for an irregular detector array in a inhomogeneous geologic medium.
7 FIG. 2a is an illustration of the cavity target reflection seismograms
8 obtained in the ideal case illustrated in FIG. la.
9 FIG. 2b is an illustration of the cavity target reflection seismograms
I 0 obtained for the practical case illustrated in FIG. lb.
I I FIG. 3 is an illustration of the "shoot-through" seismic survey field method 1 2 wherein multiple seismograms are obtained by sequentially operating the seismic 1 3 source at each detector location in the survey array layout.
1 4 FIG. 4a is an illustration of an ensemble of overlaid seismogram patterns
15 obtained by utilizing the shoot-through seismic field method with the idealized 1 6 source detector array shown in FIG. la.
1 7 FIG. 4b is an illustration of an ensemble of overlaid seismogram patterns 8 obtained by utilizing the shoot-through seismic field method with the irregular 9 detector array in a inhomogeneous geologic medium illustrated in FIG. lb.
1 Detailed Description of
2 the Preferred Embodiment
3 High resolution seismic surveys employing seismic signals in the 400-1600
4 Hz frequency range are adversely affected by small-scale inhomogeneities in the
5 geologic medium. In particular, these inhomogeneities cause a continuum of
6 backscatter interference (spatial geologic noise) which tends to mask the seismic
7 reflections from small targets of interest. These inhomogeneities have the further
8 effect of introducing relatively random variations in the two-way seismic signal
9 travel times between the source and the array of detectors. Because of these
I 0 random variations, data processing methods such as the common-depth-point trace
I I gathering and stacking method that depend upon systematic adjustments in source- 1 2 to-detector signal travel times to account for the wave propagation ray path 1 3 geometries and velocity structure of the medium will not be effective. That is, to be 1 4 productive, seismic reflection event time adjustments in the recorded detector signal 1 5 records must be preserved and adjusted in accuracy to within less than one 1 6 millisecond for seismic signals in the 400-1600 Hz frequency range. Therefore, in 17 contrast with conventional data processing techniques developed for lower 1 8 frequency seismic signals, the small but random time variations caused by the
1 9 geologic medium cannot be ignored if high-resolution reflection events in the
20 different detector traces are to be shifted in time and summed coherently with other
21 signal traces representing signals that travel along other geometrical paths to provide
22 spatial signal averaging and enhancement. Instead of applying this conventional
23 approach to high-resolution seismic data processing, a different method of spatial
24 filtering is needed which does not utilize trace gathering as the means for enhancing 25 the reflected target responses.
26 The present invention provides a novel method for processing data relating
27 to localized reflection targets and other forms of diffractors in a geological medium.
A qualitative understanding of the present invention can be obtained by considering seismic reflections, for example, from a small localized target such as a cylindrical cavity, first, for an idealized detector array in a homogeneous geologic medium and, second, for an irregular detector array in an inhomogeneous medium. FIGS, la and lb illustrate these two application conditions and the reflection event two-way signals and their travel times. The ideal case, shown in FIG. la, illustrates the seismogram display which would be obtained under the idealized source and detector geometry and uniform velocity conditions of this case or if the irregular surface elevations of the detectors shown in the practical case as well as the different ray path dimensions and the variations in seismic propagation velocity in the medium could be successfully corrected for in the processing and display of the high-resolution seismic signals. For the ideal case involving a homogeneous medium, as shown in FIG. la, the travel time from the source to the first detector (d2) can be calculated as: td2 = (R! + R2) / v (1) where t,j2 = the two way time for a reflection signal to travel from the source to the detector at location 2; R1.R2 = the ray path distances for downgoing and upgoing seismic waves, respectively; and v = the velocity of the elastic wave signal in the geologic medium. Likewise, the travel time of reflection signals from the source to any of the individual detectors, e.g., at location n, can be calculated as : tdn = (R1 + Rn) / v (2) However, for the practical case shown in FIG. lb, the travel times of the reflection events along each target-to-detector path are governed by a different propagation velocity because of inhomogeneities along the different ray paths. The
corresponding time for a signal to travel from the source at location no. 1 to the detector at the position d2 is given by the following equation:
where td2 = the two way time for a reflection signal to travel from the source to the detector at location 2; Rι>R2 = the ray path distances for downgoing and upgoing seismic waves, respectively; and vi, v = the average velocities of the downgoing and upgoing elastic wave signals in the geologic medium, respectively. Likewise, the general equation for the time required for a signal to travel from the source, s, at location no. 1 to any of the detectors, dn, is given by the following equation:
Similar equations can be constructed to calculate the respective travel times from source to detector for the cases in which the source is positioned at other locations. The different velocities of equations (3) and (4) are unknown parameters of the medium and cannot be resolved without applying special velocity analysis considerations not normally employed in conventional seismic data processing. FIGS. 2a and 2b illustrate the form of the example cavity target reflection seismograms that would be obtained in the ideal and practical cases illustrated in FIGS, la and lb, respectively. For the ideal case, shown in FIG. 2a, the cavity target will produce a hyperbola pattern in the seismogram display which is characteristic of the localized diffractor target and the geometry of each ray path. In one form of conventional seismic data processing practice, the reflection time shifts caused by the known or assumed ray path geometries and the velocity structure in the geologic formation are computed so as to flatten the hyperbolic curvature such that each detector output signal trace may be summed (gathered) to yield an
enhanced reflection wavelet. In the practical case, shown in FIG. 2b, the hyperbolic pattern becomes badly distorted because of the combined effects of irregular (known) detector elevations and unknown propagation velocities along each ray path, thereby prohibiting the computation of the necessary time shifts needed for alignment and summation of the signals. FIG. 3 illustrates what will be referred to as a "shoot-through" seismic survey field procedure in which the seismic source is operated at each detector location in the survey array layout to provide intentionally redundant field data for subsequent processing and analysis. In the illustration of FIG. 3, the shoot- through process is applied to a layout of 49 seismic detector locations showing the commonality of the reflection ray paths from the cavity target to each detector independent of the position of the source location on the array layout. This figure illustrates how the reflection signals from the localized target have a common origin and, with the use of a proper analysis procedure, the seismogram pattern produced by the target may be analyzed to yield discrete solutions for the unknown relative propagation velocities along each ray path and the seismogram patterns or traces combined to yield an enhanced detection of the localized target. In this concept, each source pulse signal will produce an ensemble of detector traces each of which may be portrayed as a seismogram of the form shown earlier in FIGS. 2a and 2b. The reflections from the target will produce patterns in each seismogram which will be essentially identical except for offsets in timing caused by the velocity differences along the different source signal ray paths. The fact that these patterns are identical is the essence of the diffractor target reflection enhancement technique. This technique has an advantage, which is particularly relevant to processing high-frequency seismic signals, that there is no specific need to gather the individual traces (whose travel time adjustments for velocity variations may not be accurately correctable). Instead of correcting each trace (as in
conventional processing) for enhancement summation, the entire seismogram display for each source position can be appropriately time shifted and summed to produce a usefully enhanced composite (stacked) seismogram pattern. The time shifts required to achieve the time alignment of each seismogram pattern may be further analyzed to yield accurate values of the relative seismic wave propagation velocities along the different ray paths. FIGS. 4a and 4b illustrate simplified representations of ensembles of overlaid seismogram patterns obtained from the shoot-through data acquisition process for the ideal and practical cases of FIGS, la and lb, respectively. These two-dimensional seismogram patterns are identical in shape to the seismograms shown in FIGS. 2a and 2b, even for the distorted patterns of the practical case, but are offset in time by the differences in the down-going source pulse travel times. A two-dimensional cross correlation analysis may be applied to determine the relative time offsets among the patterns and, as a byproduct, yield the individual relative average wave propagation velocity along each ray path. The patterns can then be time aligned and summed to produce an enhanced pattern. Depending upon the number of traces containing usable reflection signals from the target and the number of source positions used to illuminate the target, the enhancement gain of this processing technique may be exceptionally high. In the examples shown in FIGS. 4a and 4b, (all detector channels responding to the target and the source occupying every detector position), the enhancement gain factor for diffractor targets will be approximately equal to the square root of the number of source positions. The important aspects of this new concept are: (1) It is specialized to localized reflector targets such as a cylindrical cavity but is generally applicable to many forms of diffractor targets; (2) only those reflection rays traveling the same paths are combined in the pattern enhancement process and, therefore, there is no
need for geometrical or velocity corrections in the travel times prior to applying the seismogram pattern enhancement process; (3) the two-dimensional pattern enhancement process provides diffractor target detection enhancement in a manner essentially independent of the inhomogeneous characteristics of the geologic medium. Although the description of the seismic reflection signal enhancement concept presented abo- "; employed two-dimensional illustrations to facilitate the explanation of the method in a simplified way, the enhancement method of this invention is sufficiently general to be equally applicable to reflections which are observed in three dimensions. That is, the illustrations used earlier to describe the method depicted a reflection target located directly under the survey line and, hence, in the vertical plane containing the detector array. The diffractor target need not be constrained to this two-dimensional survey layout orientation for the enhancement method to be applicable. In the more general case, the target may be laterally located away from the vertical plane of the detector array to comprise a three- dimensional source-target-detector orientation. Further, if the diffractor target has extended edges, the reflections will be more complicated than those used in describing the method but, nevertheless, may be analyzed by taking into account the effects of the three-dimensional geometry. While the method and apparatus of the present invention has been described in connection with the preferred embodiment, it is not intended to be limited to the specific form set forth herein, but on the contrary, it is intended to cover such alternatives, modifications and equivalents as may be reasonably included within the spirit and scope of the invention as defined by the appended claims.
Claims
What is claimed is: 1. A method for enhanced detection of diffractor targets in a geologic medium, comprising the steps of: (a) placing a seismic wave source and a plurality of seismic wave detectors in a spaced pattern in said geologic medium; (b) generating a seismic wave from said source at a first location within said pattern; (c) detecting arrival of said seismic wave at each said seismic wave detector at each other location within said pattern after reflection by an underground diffractor target, thereby obtaining a first set of seismic traces; (d) interchanging said source with the detector at the location next adjacent thereto within said pattern and generating a next seismic wave from said next location; (e) detecting arrival of said next seismic wave at each said seismic wave detector at each other location within said pattern after reflection by said underground diffractor target, thereby obtaining a next set of seismic traces; (f) repeating steps (d) and (e) until seismic traces have been obtained for seismic waves generated at all locations within said pattern and a plurality of sets of seismic traces have been obtained therefrom; and (g) combining said plurality of sets of seismic traces to obtain an enhanced composite seismogram pattern of said seismic waves reflected by said target.
2. The method according to claim 1, said step of combining said plurality of sets of seismic traces further including the step of time shifting each said set of seismic traces and summing said plurality of sets of traces.
3. The method according to claim 2, further including the step of processing said sets of seismic traces using a two-dimensional cross correlation analysis to obtain an indication of the individual relative average wave propagation velocity for each ray path within said plurality of data sets.
A method for enhanced detection of diffractor targets in an inhomogeneous geologic medium having an irregular surface, comprising the steps of: (a) placing a seismic wave source and a plurality of seismic wave detectors in a spaced pattern in said geologic medium; (b) generating a high frequency seismic wave from said source at a first location within said pattern; (c) detecting arrival of said high frequency seismic wave at each said seismic wave detector at each other location within said pattern after reflection by an underground diffractor target, thereby obtaining a first set of seismic traces; (d) interchanging said source with the detector at the location next adjacent thereto within said pattern and generating a next high frequency seismic wave from said next location; (e) detecting arrival of said next high frequency seismic wave at each said seismic wave detector at each other location within said pattern after reflection by said underground diffractor target, thereby obtaining a next set of seismic traces; (f) repeating steps (d) and (e) until seismic traces have been obtained for high frequency seismic waves generated at all locations within said pattern and a plurality of sets of seismic traces have been obtained therefrom; and (g) combining said plurality of sets of seismic traces to obtain an enhanced composite seismogram pattern of said high frequency seismic waves reflected by said target, said enhanced pattern being obtained independent of the inhomogeneous characteristics of the geologic medium.
5. The method according to claim 4, said step of combining said plurality of sets of seismic traces further including the step of time shifting each said set of seismic traces, with no prior information regarding the relative wave velocity of the high frequency seismic wave along individual ray paths comprising said traces, and summing said plurality of sets of traces.
6. The method according to claim 5, further including the step of processing said sets of seismic traces using a two-dimensional cross correlation analysis to obtain an indication of the individual relative average wave propagation velocity for each ray path within said plurality of data sets.
7. The method according to claim 6, said seismic source generating a high frequency seismic wave pulse having a frequency spectrum in the 400 to 1600 Hz range.
8. The method according to claim 7, said time shifting and summing of said plurality of sets of seismic traces providing an enhancement of said seismogram pattern proportional to the square root of the number of source locations.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/US1990/001772 WO1991015783A1 (en) | 1990-04-03 | 1990-04-03 | Enhanced detection of seismic diffractor targets |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/US1990/001772 WO1991015783A1 (en) | 1990-04-03 | 1990-04-03 | Enhanced detection of seismic diffractor targets |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO1991015783A1 true WO1991015783A1 (en) | 1991-10-17 |
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ID=22220770
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/US1990/001772 WO1991015783A1 (en) | 1990-04-03 | 1990-04-03 | Enhanced detection of seismic diffractor targets |
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| Country | Link |
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| WO (1) | WO1991015783A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7545704B2 (en) * | 2007-02-13 | 2009-06-09 | Landmark Graphics Corporation | Performing 3-D scatterer imaging from 2-D seismic data |
| US7948829B2 (en) * | 2009-09-28 | 2011-05-24 | The United States Of America As Represented By The Secretary Of The Navy | Locator system and method including node and target acquisition |
| US8045417B2 (en) | 2007-02-13 | 2011-10-25 | Landmark Graphics Corporation | Analyzing 2-D surface and/or borehole seismic data to locate subsurface diffractors |
| WO2012107792A1 (en) * | 2011-02-08 | 2012-08-16 | Total Sa | Method of analyzing seismic data |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3040833A (en) * | 1957-01-14 | 1962-06-26 | Phillips Petroleum Co | Seismic exploration |
| US3088541A (en) * | 1959-11-24 | 1963-05-07 | Jersey Prod Res Co | Seismic exploration |
| US3601790A (en) * | 1969-09-03 | 1971-08-24 | Exxon Production Research Co | Common depth point seismic prospecting |
| US3638176A (en) * | 1970-01-05 | 1972-01-25 | Marathon Oil Co | Seismic diffraction scan |
| US4232378A (en) * | 1978-09-20 | 1980-11-04 | Standard Oil Company (Indiana) | Formation absorption seismic method |
-
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- 1990-04-03 WO PCT/US1990/001772 patent/WO1991015783A1/en unknown
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3040833A (en) * | 1957-01-14 | 1962-06-26 | Phillips Petroleum Co | Seismic exploration |
| US3088541A (en) * | 1959-11-24 | 1963-05-07 | Jersey Prod Res Co | Seismic exploration |
| US3601790A (en) * | 1969-09-03 | 1971-08-24 | Exxon Production Research Co | Common depth point seismic prospecting |
| US3638176A (en) * | 1970-01-05 | 1972-01-25 | Marathon Oil Co | Seismic diffraction scan |
| US4232378A (en) * | 1978-09-20 | 1980-11-04 | Standard Oil Company (Indiana) | Formation absorption seismic method |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7545704B2 (en) * | 2007-02-13 | 2009-06-09 | Landmark Graphics Corporation | Performing 3-D scatterer imaging from 2-D seismic data |
| US8045417B2 (en) | 2007-02-13 | 2011-10-25 | Landmark Graphics Corporation | Analyzing 2-D surface and/or borehole seismic data to locate subsurface diffractors |
| US8233351B2 (en) | 2007-02-13 | 2012-07-31 | Landmark Graphics Corporation | Analyzing borehole seismic data to locate subsurface diffractors |
| US7948829B2 (en) * | 2009-09-28 | 2011-05-24 | The United States Of America As Represented By The Secretary Of The Navy | Locator system and method including node and target acquisition |
| WO2012107792A1 (en) * | 2011-02-08 | 2012-08-16 | Total Sa | Method of analyzing seismic data |
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