PTAB

IPR2015-00311

WesternGeco LLC v. PGS Geophysical As

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Method for determining signal components attributable to respective seismic energy sources
  • Brief Description: The ’981 patent discloses a method for seismic surveying where multiple seismic energy sources are fired in sequences. The method aims to separate the recorded signals from each source by varying the time delay between the firing of a first and second source in each successive firing sequence.

3. Grounds for Unpatentability

Ground 1: Anticipation - Claims 31, 32, and 36-38 are anticipated by De Kok.

  • Prior Art Relied Upon: De Kok (Patent 6,545,944).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that De Kok discloses all limitations of the challenged claims. Specifically, independent claim 31 requires firing two sources in a plurality of sequences where the time delay between the firings is different in different sequences. Petitioner asserted that De Kok’s Figure 5A and its description teach a method using two sources (TD1, TD2) in a sequential series of shots (1-4), explicitly stating they have "different delay codes for successive shots." This varying time delay, used for signal separation, was argued to directly read on the core limitation of claim 31. The dependent claims were also allegedly disclosed, as De Kok teaches systematic time shifts (claim 32) and processing in the common mid-point (CMP) domain (claims 36-37).
    • Key Aspects: Petitioner contended that while De Kok teaches a more sophisticated technique involving both time delay and polarity encoding, the claims of the ’981 patent do not exclude such additional steps and are therefore fully anticipated.

Ground 2: Obviousness over Beasley and Timoshin - Claims 31-38 are obvious over Beasley in view of Timoshin.

  • Prior Art Relied Upon: Beasley (Patent 5,924,049) and Timoshin (Soviet Union Patent No. 1,543,357).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Beasley teaches a marine seismic survey system using two or more sources fired simultaneously or near-simultaneously, where the sources may emit "encoded wavefields using any desired type of coding" for later separation. However, Beasley does not explicitly disclose the specific time-variation encoding of the ’981 patent. Timoshin, which issued more than a decade prior, allegedly remedies this by disclosing a method of separating signals from overlapping sources by using random numbers as launch delays. Petitioner contended that Timoshin's use of varying random delays for successive shots teaches the key limitation of claim 31.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA), seeking to implement Beasley’s generalized concept of "encoding," would have been motivated to look to known encoding techniques. Timoshin provided a known and established method—varying firing delays—to achieve the predictable result of signal separation in a simultaneous source environment. Petitioner also argued it was commonplace to adapt land-based solutions (Timoshin) to marine applications (Beasley).
    • Expectation of Success: Combining the known time-encoding technique from Timoshin with Beasley’s marine survey system would predictably allow for the separation of wave fields from different sources during data processing.

Ground 3: Obviousness over Beasley and Edington - Claims 31-38 are obvious over Beasley in view of Edington.

  • Prior Art Relied Upon: Beasley (Patent 5,924,049) and Edington (Patent 4,953,657).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground presented a similar argument to Ground 2, but substituted Edington for Timoshin. As with the previous ground, Beasley provided the foundational system of simultaneous marine seismic surveying with encoded sources. Edington, also a decade-old reference, was presented as teaching the missing element: varying the time delay between source firings in successive shots. Edington explicitly discloses shooting two sources with a determinable time delay and then shooting them again with a different determinable time delay to distinguish the signals.
    • Motivation to Combine: The motivation was identical to that asserted in Ground 2: a POSITA implementing Beasley’s general system would naturally look to known and specific encoding techniques like that disclosed in Edington. The similarities between the references, both dealing with simultaneous shooting and signal encoding, would provide a strong motivation to combine their teachings.
    • Expectation of Success: A POSITA would have had a high expectation of success in applying Edington’s specific time-delay variation method to Beasley’s system to achieve the well-understood goal of signal separation.

4. Key Claim Construction Positions

  • "wavelet time" (Claim 35): Petitioner proposed that this term, which is not explicitly defined in the ’981 patent, should be construed to mean "the duration of the source signature."
    • Argument: This construction was based on the specification's guidance that the time delay should be at least as long as the "wavelet time" to avoid interference between the source signals. Petitioner’s expert declared that a POSITA would understand that waiting for the duration of the source signature is a known technique to prevent the primary source signals from overlapping, which is a prerequisite for effective signal separation. This construction was important for the obviousness argument for claim 35, as preventing signal interference is a basic and obvious design choice.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 31-38 of Patent 6,906,981 as unpatentable.