PTAB

IPR2015-00309

WesternGeco, L.L.C. v. PGS Geophysical AS

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1. Case Identification

2. Patent Overview

  • Title: Method for Seismic Surveying
  • Brief Description: The ’981 patent discloses a method for marine seismic surveying using multiple towed energy sources. The core of the invention involves actuating the sources in a plurality of firing sequences where the time interval between the firing of a first source and a second source is varied between successive sequences, which allegedly enables separate identification of the resulting seismic signals during processing.

3. Grounds for Unpatentability

Ground 1: Anticipation by De Kok - Claims 1, 2, 7, and 10-21 are anticipated under 35 U.S.C. §102 by De Kok.

  • Prior Art Relied Upon: De Kok (Patent 6,545,944).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that De Kok, which discloses techniques for acquiring seismic data using simultaneously activated sources, teaches every element of the challenged claims. Petitioner argued that even though the ’981 patent does not disclose polarity decoding, its claims do not exclude it, and therefore De Kok’s more sophisticated method, which uses both time-delay and polarity encoding, falls within the scope of the claims under the broadest reasonable interpretation. Specifically, Petitioner pointed to De Kok’s disclosure of sequential series of shots having "different delay codes for successive shots" as directly teaching the ’981 patent’s central limitation of varying the time interval between firings over successive sequences.

Ground 2: Obviousness over Beasley and Timoshin - Claims 1-22 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 general framework for marine seismic surveys using multiple, simultaneously or near-simultaneously fired sources and explicitly suggests that the "sources may be arranged to emit encoded wavefields using any desired type of coding." However, Beasley does not specify the exact time-encoding method of the ’981 patent. Timoshin, an older reference concerning land-based seismic surveys, was asserted to supply this missing element by teaching the use of random numbers as launch delays to distinguish signals from overlapping sources. Petitioner contended that Timoshin’s random delays directly teach the ’981 patent’s requirement to vary the time interval between firings.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine the references because it was common practice in the field to adapt known land-based solutions (like Timoshin's encoding) to marine survey systems (like Beasley's). The combination would simply apply a known technique to a known system to yield the predictable result of improved source separation. The shared context of simultaneous shooting, encoding, and decoding provided a strong motivation for the combination.
    • Expectation of Success: Petitioner asserted a high expectation of success, as the combination involved applying a known technique (time-delay encoding) for its intended and well-understood purpose.

Ground 3: Obviousness over Beasley and Edington - Claims 1-22 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 parallels Ground 2, with Beasley again providing the foundational marine survey system. Edington was substituted for Timoshin, with Petitioner arguing it was not redundant because Edington more explicitly discloses varying the timing of firings across multiple shot sequences. Edington teaches activating sources with a determinable time delay, and then shooting them a second time with a different determinable time delay, with the difference being selected specifically "to enable the signal received from the first activated source to be distinguished from the signal received from the second activated source."
    • Motivation to Combine: The motivation was argued to be identical to that in Ground 2. A POSITA seeking to implement source encoding in Beasley's system would have looked to known encoding techniques like that in Edington. Implementing Edington’s specific time-encoding technique into Beasley’s general system was presented as an obvious design choice to solve the known problem of separating signals from simultaneous sources.
    • Expectation of Success: Success was argued to be predictable, as it involved the straightforward combination of familiar elements according to known methods to achieve a known result.

4. Key Claim Construction Positions

  • Term: "wavelet time" (from claim 6, which requires the time interval to be "at least as long as a wavelet time of the first source").
  • Petitioner's Proposed Construction: Petitioner argued the broadest reasonable interpretation of "wavelet time" is "the duration of the source signature."
  • Justification: This construction was based on the ’981 patent specification’s stated preference for selecting a time delay long enough "to avoid interference between the first and second sources." Petitioner contended that a POSITA would understand this to mean avoiding interference between the direct source signatures themselves (as opposed to their reflections), making it obvious to wait at least the duration of the signature before firing the second source. This interpretation was critical to Petitioner's obviousness argument for dependent claim 6.

5. Relief Requested

  • Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 1-22 of the ’981 patent as unpatentable.