Application of Johnson

• Decision Date: 15 February 1979
• Docket Number: Appeal No. 76-717 to 76-719.
• Citation: 589 F.2d 1070
• Parties: Application of Jay P. JOHNSON, Alvin L. Parrack and Delbert R. Lunsford. Application of Alvin L. PARRACK and Delbert R. Lunsford (two cases.)
• Court: U.S. Court of Customs and Patent Appeals (CCPA)

589 F.2d 1070

Application of Jay P. JOHNSON, Alvin L. Parrack and Delbert R. Lunsford.

Application of Alvin L. PARRACK and Delbert R. Lunsford (two cases.)

Appeal Nos. 76-717 to 76-719.

United States Court of Customs and Patent Appeals.

December 7, 1978.

Rehearing Denied February 15, 1979.

William J. Beard, attorney of record, Houston, Tex., for appellants.

Joseph F. Nakamura, Washington, D. C., for the Commissioner of Patents; Jere W. Sears, Washington, D. C., of counsel.

Before MARKEY, Chief Judge, and RICH, BALDWIN, LANE and MILLER, Judges.

BALDWIN, Judge.

These appeals are from the decisions of the Patent and Trademark Office (PTO) Board of Appeals (board) sustaining the rejections of all claims in three consolidated cases¹ under 35 U.S.C. § 101 for being directed to nonstatutory subject matter.² We reverse on all claims.

The Inventions

The inventions before us involve methods for removing undesired components (noise) from seismic data. In seismic prospecting, an acoustic or seismic wave energy source is positioned either in a relatively shallow shot hole on the surface of the earth, or is towed a predetermined distance beneath the surface of a body of water. An acoustic energy impulse of some preselected wave shape and frequency content is generated by the seismic energy source. The acoustic energy generated by the source penetrates through the multiple layers of material comprising the subterranean portion of the earth in the region being prospected. Since the speed of sound is generally different in each layer beneath the surface of the earth, refractions, reflections, and diffractions of the acoustic energy occur at the boundary of each layer. These acoustic energy reflections, refractions, and diffractions cause secondary acoustic energy waves to return toward the surface of the earth. At the surface, the returning acoustic energy waves are detected by a plurality of longitudinally-spaced geophones, hydrophones, or seismic detectors. The individual seismic detectors are located along a generally straight line. These detectors generate analog electrical signals or waveforms which are representative of the arrival of the acoustic energy waves at the detectors. The analog waveforms generated by the seismic detectors are, thus, voltage representations, generated as a function of time, of the amplitude of reflected, refracted, and diffracted secondary acoustic energy waves arriving at the surface of the earth.

The secondary waves detected by the seismic detectors are generally amplified and then recorded or stored in either analog or digital form on a record medium as a function of the time after the seismic "shot" or energy generation. After amplification and prior to recording, the analog electrical waveform may be digitized by sampling its amplitude at a predetermined rate and then recording the digital amplitude values as a function of time. A time series of digital numbers representative of the amplitude of the analog waveform at each detector as a function of time is thus generated. The recorded representation of seismic energy at a detector location, whether it is recorded in analog or digital form, may be displayed for interpretation in the form of a "wiggle trace" or plot of the amplitude of the arriving acoustic energy waves as a function of time for each geophone or seismic detector stationed at a particular surface location. A plurality of such traces forms a record section of the data. These record sections may then be processed to interpret the arriving acoustic energy waves at each seismic detector in terms of the subsurface layering of the earth structure. This analysis, if performed properly, can disclose the location of subterranean earth structures or traps which may contain petroleum deposits. It is quite common for seismic data to be recorded in digital form as described and for digital data processing equipment (i. e., digital computers) to be used in the processing of the seismic data for interpretation in terms of the location of subterranean structures which may be petroleum traps.

The inventions in each of the three applications in these consolidated appeals deal with the removal of unwanted seismic signal components or noise present in the recorded seismic data. Noise removal facilitates interpretation of the seismic data and, thereby, determination of subterranean structure. This undesired acoustic noise which appears on the records of seismic data may be caused by a variety of noise sources. One type of noise, called "multiple reflections," involves an "echo" effect caused by hard layers near the surface which "trap" and rebroadcast the primary acoustic energy impulse of the source several times rather than just once. The arrival at the detectors of each repetitive reflection (or reverberation) causes the detector to perceive nonexistent deep layers, and the echoes mask the true signal. Other sources of noise are electrical interference from power lines or communication systems in use in the vicinity of the seismic exploration and random acoustic energy noise from other energy sources, such as vehicles moving in the region of the seismic exploration. Thus, the removal of noise or undesired signal components from the recorded data representations comprising a seismic record is a problem in the seismic exploration technique practiced in the petroleum industry.

Application serial No. 230,810 (Appeal No. 76-719) is the first-filed application of the three related applications presently on appeal. The invention disclosed in this application comprises a technique for removing unwanted noise components from the seismic traces in a seismic record in which certain conventional seismic data processing techniques, such as the correction for "normal move out" and the "stacking" or adding technique which is applied to Common Depth Point (CDP) seismic data, have already been performed. The invention makes use of the physical principle that, because of the manner in which the seismic data are gathered, closely adjacent detectors should receive reflections of essentially the same wave shape from a given layer. A chronologically small portion of a particular seismic trace (termed a reference trace) is examined and is compared with corresponding portions of spatially adjacent seismic traces in order to define a coherent signal component common to all of the traces being examined. The coherent signal component is then separated from the totality of the recorded seismic data present in the portion of the reference trace being examined, and the remainder is considered noise. The assumption present in such processing is that there should be relatively few abrupt changes in the physical characteristics of the subsurface bed boundaries as a function of horizontal distance. Claim 1 in Appeal No. 76-719 recites:

1. A machine implemented method for enhancing digital data in a seismic record, said data having a coherent signal component comprising a measure of the similarity between spatially related time series data, and a noice sic noise component, and for improving the signal to noise ratio thereof, comprising the steps of:

determining, for a search window defined about a selected time on a selected seismic reference trace, the coherent signal associated with said reference trace and a plurality of adjacent seismic traces;

computing, by use of said coherent signal, the component of said coherent signal extant in said reference trace and replacing in time alignment with said reference trace on an output signal record medium, that portion of said reference trace included in said search window with said component of the reference trace comprising said coherent signal portion;

replacing, in time alignment with said reference trace on an output noise record medium, that portion of said reference trace included in said search window, with the remainder of said reference trace which does not comprise said coherent signal portion; and

repeating the above steps for other selected times and other selected reference traces until all data comprising said record is so processed.

Claim 10 in this appeal recites:

10. A machine implemented method for enhancing digital data in a Common Depth Point, moveout corrected and stacked seismic data record, said data having a coherent signal component comprising a measure of the similarity between spatially related time series data, and a noise component, and for improving the signal to noise ratio thereof, comprising the steps of:

determining, for a search window defined about a selected time on a selected seismic reference trace, the shape of the coherent signal associated with said selected reference trace and a plurality of spacewise adjacent seismic traces;

determining, for said search window, the amplitude of said coherent signal;

computing, as a function of the amplitude and shape information pertaining to said coherent signal, the component portion of said selected reference trace corresponding to said coherent signal;

replacing, in time alignment with said selected reference trace, on an output signal record medium the portion of said selected reference trace in said search window, with said coherent signal component portion; and repeating the above steps for other selected times and other selected reference traces until all data comprising said record is so processed.

The remaining independent claim in Appeal No. 76-719 is claim 16 which states:

16. A machine implemented method for enhancing plural raw digital data records, not moveout corrected, said data having a coherent signal component comprising a measure of the similarity between spatially related time series data, and a noise component, and for improving the signal to noise ratio thereof, comprising the steps of:

compiling, from said plurality of raw data records, a synthetic data record of common range traces;

determining, for a search window defined about a selected time on a selected

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