High frequency retention seismic survey method
First Claim
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1. A process for creating a seismic section from traces received from seismic signal receivers, the process comprising:
- generating a first common reflection point gather of a first set of traces, wherein the first set of traces represent seismic signals originating from a first source point, the first source point comprising multiple source element locations;
synchronizing a plurality of the first set of traces within the first common reflection point gather;
adding the synchronized signals within the first common reflection point gather;
generating a second common reflection point gather of a second set of traces, wherein the second set of traces represent seismic signals originating from a second source point, the second source point comprising multiple source element locations;
synchronizing a plurality of the signals within the second common reflection point gather;
adding the synchronized signals within the second common reflection point gather;
wherein the first and the second source points are at least about as far apart as one-half the distance along the traverse covered by the receiver groups when receiving signals, and wherein the seismic signals received from the first and second source points are continuous samplings along the traverse from the same depth level.
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Abstract
Methods for generating seismic data and creating a seismic section are disclosed in which the difference in offsets between stacked traces is limited.
27 Citations
47 Claims
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1. A process for creating a seismic section from traces received from seismic signal receivers, the process comprising:
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generating a first common reflection point gather of a first set of traces, wherein the first set of traces represent seismic signals originating from a first source point, the first source point comprising multiple source element locations; synchronizing a plurality of the first set of traces within the first common reflection point gather; adding the synchronized signals within the first common reflection point gather; generating a second common reflection point gather of a second set of traces, wherein the second set of traces represent seismic signals originating from a second source point, the second source point comprising multiple source element locations; synchronizing a plurality of the signals within the second common reflection point gather; adding the synchronized signals within the second common reflection point gather; wherein the first and the second source points are at least about as far apart as one-half the distance along the traverse covered by the receiver groups when receiving signals, and wherein the seismic signals received from the first and second source points are continuous samplings along the traverse from the same depth level. - View Dependent Claims (2, 3, 4)
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5. A process for creating high quality field records in seismic data gathering comprising:
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a) generating a first seismic signal at a source point; b) receiving reflections of the first seismic signal at a plurality of receivers, and receiving noise at the plurality of receivers while receiving the reflections of the first seismic signal, the reflections and the noise defining a first received signal; c) recording the first received signal, thus defining a recorded signal; d) generating a second seismic signal at a source point; e) receiving reflections of the second seismic signal at a plurality of receivers, and receiving noise at the plurality of receivers while receiving the reflections of the second seismic signal, the reflections and the noise defining a second received signal; f) adding the second received signal to the recorded signal, thus defining an added signal, the ratio of the amplitude of the reflections of the seismic signal in the added signal to the amplitude of the noise in the added signal defining a signal-to-noise ratio; g) recording the added signal, to replace the recorded signal; h) repeating steps d through f until the signal-to-noise ratio is 0.2 or greater. - View Dependent Claims (6, 7, 8, 9, 10)
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11. A process for generating a seismic section from multiple traces recorded from seismic receivers along a traverse and reducing the degradation of high frequencies, the process comprising:
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defining an offset limit for synchronization of traces having a common reflection point; choosing at least two traces, the difference in offset between the two traces being about equal to or less than the offset limit; synchronizing the at least two traces; and adding the at least two traces. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A process for suppression of a predetermined wavelength L of horizontal noise in seismic data comprising:
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choosing a first set of traces at a first set of receiver groups, the first set of receiver groups being spaced by m receiver group intervals, the receiver group interval having a length of about d, each of the first set of traces being from a first source cluster, the first source cluster being located at a first source point having k source clusters; choosing a second set of traces at a second set of receiver groups, the second set of receiver groups being spaced by m receiver group intervals, the receiver group interval having a length of about d, each of the second set of traces being from a second source cluster, the second source cluster being located at the first source point; grouping traces from the first and second sets of traces into a first set of gathers, wherein the midpoint between the source cluster and the receiver group for each trace in any gather is the same; synchronizing each trace in a particular gather of the first set of gathers with every other trace in the particular gather, thus defining a synchronized set of traces; repeating the synchronizing for each gather in the first set of gathers; adding the synchronized traces, whereby a set of added traces is defined, one added trace for each of the first set of gathers; defining an integer q equal to the greater of the receiver group length or the source cluster length, in units of receiver group intervals; generating a set of running sum traces from the set of added traces with an n-trace running sum, according to the following relationships;
space="preserve" listing-type="equation">n=(2m)/q and (L/d)=2mk+(q/2). - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A process for conformal mapping comprising:
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a) defining a reference trace; b) defining a shift amount; c) defining a sample interval, the sample interval being less than the shift amount, whereby an integer n is defined as the ratio of the shift amount to the shift interval; d) shifting a second trace in time n times, whereby a set of n shifted traces are defined; e) multiplying a plurality of the set of shifted traces by either the reference trace or the second trace, whereby a set of product traces are defined; f) setting a plurality of the negative portions in a plurality of the set of product traces about zero, whereby a set of zero-corrected product traces is defined; g) filtering a plurality of the set of zero-corrected product traces with a filter having a shape similar to the envelope of the wavelet that generated either the reference trace, whereby a filtered set of product traces is defined; h) remapping the second trace such that each wavelet complex of the second trace is time shifted by the amount of shift of the product trace from the set of product traces that includes the maximum response for that wavelet complex. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37)
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38. A process for seismic data gathering comprising:
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collecting a first set of multiple signals from a first set of ray paths, wherein the first set of ray paths originate from a first source point and are received at a first receiver point; organizing a plurality of the first set of multiple signals into a first set of clusters, wherein the furthest spaced traces of a first specific cluster of the first set of multiple clusters are spaced no greater than a distance at which a predetermined fmax is attenuated less than a predetermined factor K upon addition of the furthest spaced traces in the first specific cluster; collecting a second set of multiple signals from a second set of ray paths, wherein the second set of ray paths originate from a second source point and are received at a second receiver point; organizing a plurality of the second set of multiple signals into a second set of clusters, wherein the furthest spaced traces of a second specific cluster of the second set of multiple clusters are spaced no greater than a distance at which a predetermined fmax is attenuated less than a predetermined factor K upon addition of the furthest spaced traces in the second specific cluster; adding together a plurality of the signals within the same cluster to create a cluster signal for each of a plurality of the clusters; sorting a plurality of the cluster signals into common reflection point gathers, wherein each cluster signal within any common reflection point gather has a reflection point in common with every other cluster signal in each common reflection point gather; synchronizing a plurality of the cluster signals within a plurality of the common reflection point gathers. - View Dependent Claims (39, 40, 41, 42)
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43. A process for creating a seismic section from traces received from seismic signal receivers, the process comprising:
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generating a first common reflection point gather of a first set of traces, wherein the first set of traces represent seismic signals originating from a first source point, the first source point comprising multiple source element locations spaced each from the other by a distance x which is less than or equal to the spacing distance at which addition of any two of the first set of traces results in an attenuation of a predetermined maximum frequency of interest fmax by a predetermined attenuation factor K; synchronizing a plurality of the first set of traces within the first common reflection point gather; adding the synchronized signals within the first common reflection point gather; generating a second common reflection point gather of a second set of traces, wherein the second set of traces represent seismic signals originating from a second source point, the second source point comprising multiple source element locations spaced each from the other by a distance x which is less than or equal to the spacing distance at which addition of any two of the second set of traces results in an attenuation of a predetermined maximum frequency of interest fmax by a predetermined attenuation factor K; synchronizing a plurality of the signals within the second common reflection point gather; adding the synchronized signals within the second common reflection point gather; wherein the first and the second source points are about as far apart as one-half the distance along the traverse covered by the receiver groups when receiving signals, and wherein the seismic signals received from the first and second source points are continuous samplings along the traverse from the same depth level. - View Dependent Claims (44, 45, 46, 47)
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Specification