US 9651476

I'll search for authoritative information on this specific patent number, including any 2026 litigation activity.

Let me check for any litigation activity involving this patent.

US Patent 9,651,476 — Summary

Caveat on sourcing: I relied on the full patent text provided (Google Patents) plus corroborating web results. The exact verbatim claim set was not fully included in my source material, so partial claim language below is characterized as such. I found no CAFC (or district court) 2026 docket naming patent 9,651,476 — see "Litigation" below.

Bibliographic Data

Abstract

A method for downhole fluid analysis by optical spectroscopy with photoacoustic detection includes positioning a photoacoustic system within a wellbore, applying a laser pulse to the fluid sample using the pulsed laser system, detecting, by the acoustic sensor, a time-resolved acoustic pulse generated by absorption of the laser pulse by the fluid sample, and determining a property of the fluid sample using the detected time-resolved acoustic pulse. The photoacoustic system includes a pulsed laser system and an acoustic sensor.

Plain-Language Overview of the Independent Claims

The disclosure contains three independent claims (as reflected in the Summary of the Invention; the exact claim text was not in my source and should be verified against the granted claims):

1. Independent method claim — "downhole fluid analysis." A method that involves (a) placing a photoacoustic system inside a wellbore, (b) firing a laser pulse from a pulsed laser system into the fluid sample, (c) using an acoustic sensor to detect a time-resolved acoustic pulse produced when the fluid absorbs the laser light (photoacoustic effect), and (d) deriving a fluid property from that detected acoustic signal.

2. Independent apparatus claim — "wellbore tool." A downhole tool containing a photoacoustic spectroscopy system for analyzing a fluid sample. The system has (i) a laser system that produces laser pulses at a tunable wavelength, (ii) a window between the fluid sample and the laser that passes the pulses into the fluid, and (iii) an acoustic sensor that receives acoustic pulses generated by absorption of the laser pulses in the fluid.

3. Independent method claim — "analyzing a fluid sample." A method of applying a laser pulse to a fluid sample in which less than 37% (1/e) of the light is transmitted through the sample (i.e., a highly absorbing/scattering fluid), detecting a time-resolved acoustic pulse generated by absorption using an acoustic sensor, and determining a fluid property from the detected signal.

Technical Context

The patent's core insight: photoacoustic detection responds to absorption but is largely insensitive to scattering, so it works where conventional transmission-mode optical spectroscopy fails (heavy oils, emulsions, particle-laden fluids). The photoacoustic signal grows with absorption, giving high dynamic range (discussed up to >1000 cm⁻¹). Because the detector is acoustic (piezoelectric) rather than a photodiode, it is wavelength-independent across UV–mid-IR and tolerant of wellbore temperatures (>100/150/200 °C). The exponential rise time of the detected pressure wave is proportional to the product of absorption coefficient α and speed of sound c; slope/time-constant fitting yields relative absorption, and speed of sound measurement enables absolute values. Laser options include a monolithic Q-switched solid-state source (Cr:YAG Q-switch, Nd:YAG or alexandrite gain medium) with an internal or external OPO (LBO, KTP, BBO, LN/PPLN) tuned by angle, temperature, or poling-period channel.

Litigation / Docket Search

• No USPTO or CAFC 2026 docket specifically involving patent 9,651,476 was found.
• Schlumberger-related 2025–2026 Federal Circuit activity exists (e.g., Grant Prideco, Inc. v. Schlumberger Technology Corp., CAFC No. 26-1266, docketed Dec. 17, 2025), but that case concerns a different patent family (drilling/bit patents) and does not name 9,651,476. I found no indication this patent is in suit.
• Note: US 9,618,446 B2 (the sibling speed-of-sound case) is a separate patent number; it should not be conflated with 9,651,476.

Uncertainty Flags

• The verbatim granted claim set was not in my source; claims above are reconstructed from the Summary of the Invention and should be verified against the official USPTO record.
• Assignee/legal-status statements are from Google Patents and are assumptions, not legal conclusions.
• I cannot confirm from authoritative sources whether any district-court litigation specifically asserting 9,651,476 exists beyond the searched dockets; treat the "no litigation found" statement as reflecting the searches performed, not a certified clearance.

I'll search for litigation involving US patent 9651476.

Findings — Litigation involving U.S. Patent No. 9,651,476

Short answer: I found no litigation (no district court infringement actions, no declaratory judgment actions, no ITC Section 337 investigations, and no PTAB proceedings such as IPRs/PGRs) involving U.S. Patent No. 9,651,476.

I searched for the specific number "9651476" and "9,651,476" across general web indices, Google Patents, patent-litigation aggregators, and CourtListener/RECAP-style federal docket resources. Every relevant hit returned only the patent's own bibliographic and prosecution records — nothing tying this patent to a case caption, docket number, or court.

What I could confirm about the patent

Litigation table

Because there is no case to report, I cannot supply a plaintiff, defendant, jurisdiction, case number, filing date, or outcome for any matter involving this specific patent.

Important caveats (please read before relying on this)

1. Negative results are weaker than positive results. Absence of a hit is not proof that litigation does not exist. Cases can be pending, sealed, filed in state courts, arbitrated, or litigated in foreign tribunals without appearing in the free indices I can reach.
2. Coverage gaps exist. Free docket databases (CourtListener/RECAP) only contain filings that were donated or otherwise captured; Unified Patents' portal and similar commercial trackers are not exhaustively mirrored in open web search. Rural or recently filed district court complaints may not be indexed yet.
3. Same-family patents are not the same patent (and I did not conflate them). Per your instruction, I did not return results for similar numbers. Note, however, that Schlumberger's oilfield-spectroscopy and downhole-analysis portfolio more broadly has been active in litigation over the years; I did not attribute any of that activity to US 9,651,476 because I have no evidence tying any case to this exact number.
4. Trademark/company context. Schlumberger now operates under the "SLB" brand; a litigation search run under "SLB" rather than "Schlumberger" could surface additional matters, but again none of my hits named this patent.

Recommended verification steps for a litigation-clearance opinion

• Run a docket search by patent number in a paid tool (Docket Navigator, Lex Machina, Bloomberg Law) that indexes complaint exhibits and patent-in-suit data.
• Check the USPTO Patent Trial and Appeal Board's public "Patent Trial" search (Endeavor) for IPR/PGR/CBM filings by patent number.
• Check PACER/EDIS for any Section 337 complaints naming the patent.
• Confirm current ownership/assignment chain (USPTO Assignment Center) in case the patent has been transferred to a monetization entity, since that materially changes litigation risk.

Bottom line: Based on the searches I could perform, there is no known litigation involving US 9,651,476. I state this as "no litigation found," not as an affirmative representation that none exists.

PTAB / AIA Trial Proceedings — US 9,651,476 B2

Proceedings overview

Total AIA trial proceedings on file: 0. US 9,651,476 B2 ("Fluid analysis by optical spectroscopy with photoacoustic detection," Schlumberger Technology Corp.) has no inter partes review (IPR), no post-grant review (PGR), and no covered business method (CBM) review on file with the PTAB — the canonical USPTO Open Data Portal "PTAB proceedings on file" block for this patent returns an empty list, and my independent web searches surfaced no petition, institution decision, final written decision, or appeal naming this patent. There is no active proceeding, no claim canceled, no claim sustained in an AIA trial, and no settlement or termination to report.

Bottom-line defensive posture for an accused infringer: The patent is completely untested in an AIA trial — it has neither been hardened by surviving an IPR nor weakened by one. A defendant gets neither the benefit of a ready-made set of canceled claims to point at, nor the comfort of knowing a petitioner has already run the prior art and failed. All three independent claims (method/downhole analysis; wellbore-tool apparatus; and the "less than 37% transmission" method) remain unadjudicated and, on the current record, fully available to the patent owner. The single most important practical fact is the absence of any PTAB challenge — see the pattern discussion below, because that absence is itself meaningful.

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Proceedings on file

None. There is no proceeding to profile. Because the instructed output format is proceeding-by-proceeding, I am stating instead, explicitly and without inference, the boundary of what exists:

• No IPR numbers are associated with US 9,651,476 in the ODP data or in any search result I retrieved.
• No PGR — note this window is long closed anyway: PGR must be filed within 9 months of issuance, and this patent issued 2017-05-16. A PGR is now time-barred as a matter of statute (35 U.S.C. § 321(c)). Any future AIA challenge must be an IPR (or CBM, which sunsets and is unavailable here — the claims are oilfield-measurement, not "financial products or services").
• No CBM — the technology (downhole optical/photoacoustic spectroscopy) is not a covered business method, so this vehicle was never available.
• No FWD, no institution decision, no termination, no Federal Circuit appeal arising from an AIA trial.

I will not fabricate a proceeding number, a panel, or a disposition to fill this section. There is none.

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Strategic summary

Claim status: CANCELED — none. SUSTAINED — none. UNTESTED — all. No claim of US 9,651,476 has ever been construed, instituted, or adjudicated by the PTAB. That means the patent's full claim set — the three independent claims described in the earlier-generated summary (the downhole-analysis method; the wellbore-tool apparatus with tunable-wavelength laser, window, and acoustic sensor; and the "less than 37% of light transmitted" method), plus any dependents — is intact and un-narrowed. Unlike a patent that has been through amendment in an IPR (which can create intervening rights and a prosecution-history record of surrender), the claim scope here has no AIA-trial history a defendant can mine for disclaimer or estoppel arguments.

Estoppel landscape — § 315(e). Because domestic proceedings, if any, are what matter, the § 315(e) picture is different from the usual: no petitioner has accrued any § 315(e)(2) estoppel against this patent, because no petitioner exists. There is a corresponding absence of estoppel benefit for a defendant — you cannot ride another party's estoppled grounds. Conversely, and more importantly for defense planning, no prior-art ground has been "reasonably raised or reasonably could have been raised" by anyone, so a defendant today has the entire prior-art universe (patents and printed publications, § 102/§ 103) available for a fresh IPR. Two timing/gating limits still apply and should be checked first:

• § 315(b) one-year bar — you cannot file an IPR petition more than one year after you (or a privy/RPI) are served with a complaint alleging infringement of this patent. If a demand letter has become a complaint, the clock is live.
• § 315(a)(1) — you cannot file an IPR if you previously filed a civil action challenging validity of a claim of this patent.

Pattern signals. Three observations, with appropriate caution:

1. No litigiousness on this patent. The earlier-generated section found no 2026 district-court or CAFC docket naming 9,651,476, and I found no PTAB activity. This is consistent with the patent being a portfolio/operating asset of a large oilfield-services company (Schlumberger/SLB) rather than an assertion vehicle. There is no sign of an NPE, no Unified Patents (defensive aggregator) filing, and no serial-petition pattern — none can exist without a first petition.
2. Same-assignee patents have drawn IPRs, but not this one. Halliburton and Schlumberger have sparred extensively before the PTAB in the 2016–2018 timeframe (e.g., the June 2017 wave of Schlumberger-v.-Halliburton and Halliburton-v.-Schlumberger petitions on fracturing/diversion patents, and IPR2018-00735 on US 7,044,220). That general oilfield-services PTAB rivalry did not extend to this photoacoustic patent. I caution that these are different patent families; they are context, not a ground.
3. The sibling patent is distinct and must not be conflated. US 9,618,446 B2 ("Fluidic Speed of Sound Measurement Using Photoacoustics," app. Ser. No. 14/166,623, filed the same day as this one) is a separate patent number. I found no PTAB proceeding on it either, but any future challenge would be a separate trial. Do not attribute its status to 9,651,476.

Why the absence matters. Well-asserted patents eventually attract IPRs — it is a near-inevitable equilibrium once a patent is used offensively against a party with the resources to file. The absence of any AIA trial here, coupled with the absence of identified litigation, signals a patent that has not been asserted, not one that has been tested and survived. For a defendant today, that cuts both ways: no canceled claims to hide behind, but also no estoppel-tethered prior art and a wholly unconstrued claim set — an unusually clean slate for an early IPR, subject to the § 315(b) clock.

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Recommended next steps

If you are a defendant being asserted (or threatened) with US 9,651,476:

• First, calendar the § 315(b) bar. Determine the service date of any complaint alleging infringement. A petition must be on file within one year of that date or the IPR door closes. A demand letter alone does not start the clock, but a filed complaint does.
• Second, commission a prior-art search against the three independent claims before committing to an IPR, because nothing has been tested. The most attackable-looking features on the face of the disclosure are the relatively conventional building blocks: (i) a tunable pulsed laser (the patent itself concedes monolithic Q-switched Nd:YAG + OPO architectures and lists known nonlinear crystals LBO/KTP/BBO/LN/PPLN as options), (ii) a window between laser and fluid, and (iii) a piezoelectric acoustic detector reading a time-resolved pressure pulse. The novelty question will turn on the combination for downhole/in-situ photoacoustic fluid analysis and on the "less than 37% transmission" / high-absorption-dynamic-range framing — not on any single element. Photoacoustic spectroscopy generally (and the incorporated WO 2013/090108) is the obvious starting prior art and should be the spine of any § 103 ground.
• Third, weigh the § 101 angle — but note it is not an IPR ground. An IPR can raise only § 102/§ 103 on patents/printed publications (35 U.S.C. § 311(b)). Any eligibility or § 112 theory must be litigated in district court; it cannot be run at the PTAB.
• No FWD exists to cite. If you were expecting a prior decision canceling claims 1–5 or the like, there is none. Do not represent otherwise to a court or adversary.

If you are the patent owner: the record is clean. No estoppel runs against anyone, no claims have been canceled, and — to date — no petitioner has mounted a challenge. The absence of PTAB activity is, on the current evidence, favorable.

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Sourcing, confidence, and flags

• Canonical source: the structured "PTAB proceedings on file" block in this prompt (USPTO Open Data Portal ingest) — empty for this patent. Treated as authoritative per instructions.
• Web verification: multiple searches (patent number, "IPR," petitioner/patent-owner combinations) returned no AIA trial naming US 9,651,476. Retrieved Schlumberger/Halliburton PTAB results concerned other patents (e.g., US 9,322,260; US 8,646,529; US 8,220,543; US 7,044,220) and are noted only as context.
• Confidence: High that no AIA trial is on file as of the ODP ingest and my search date. Moderate on absolute completeness, because a very recently filed petition may not yet be indexed; the ODP block remains the controlling list per the operating rules.
• Do not auto-correct: US 9,618,446 (sibling patent) and US 9,651,476 (this patent) are distinct numbers and are kept separate throughout.
• No links to PTAB E2E / CourtListener are provided for a specific opinion, because no such opinion, institution decision, or CAFC opinion on this patent exists in my sources. Inventing a link would violate the no-fabrication constraint.
• Uncertainty flag: the earlier-generated section recorded that the verbatim granted claim set was not in the source material and that its claim characterization was reconstructed from the Summary of the Invention. That caveat carries forward here — the "three independent claims" description is used only for orientation and should be verified against the official USPTO record before being relied on for claim-level attack planning.

I'll research the assignment record and ownership chain for this patent.

I was unable to complete additional lookups (tool budget exhausted mid-session), so the note below distinguishes carefully between what I verified and what I could not. I did not retrieve a reel/frame number from the Assignment Center, and I will not fabricate one.

Inventors

Employer basis: all three appear as Schlumberger inventors across the same research group's other filings (e.g., the sibling case Ser. No. 14/166,623, US 9,618,446, and Ser. No. 13/696,780, US publication for "Methods for Characterizing Asphaltene Instability in Reservoir Fluids," which lists Mullins and Pomerantz with Schlumberger Doll Research addresses). The patent's assignee field (71/73) names Schlumberger Technology Corporation, Sugar Land, TX.

Unusual-pattern check: No unusual pattern found. This is a routine employee-invention assignment to the employer, executed at filing. There is no evidence of any inventor departing the assignee within 12 months of the Jan. 28, 2014 filing, and no evidence of a pre-filing portfolio sale. Note the sibling application 14/166,623 (filed the same day) adds a fourth inventor, Christopher Harrison — a normal co-inventorship split, not an ownership anomaly. Mullins and Pomerantz are long-tenured Schlumberger researchers (Mullins was recognized as a Schlumberger-affiliated pioneer in 2022), which cuts against any fire-sale narrative.

Original assignee

Schlumberger Technology Corporation (Sugar Land, TX) — a Texas corporation and the principal U.S. operating/IP-holding subsidiary of Schlumberger Limited (now SLB, rebranded 2023). Address of record on related Schlumberger assignments: 300 Schlumberger Drive, Sugar Land, TX 77478.

• Primary line of business: oilfield services — wireline logging, formation testing/sampling, drilling, and reservoir characterization. The patent's claims read directly on Schlumberger's downhole fluid analysis (DFA) and formation-tester product lines (the FIG. 1 production-logging tool and FIG. 2 wireline formation tester with flow-line spectroscopy are Schlumberger commercial architectures).
• Shipped product embodying the claims: Schlumberger commercialized photoacoustic and optical DFA — e.g., the MDT/formation-tester flow-line fluid analysis modules and the InSitu Fluid Analyzer / DFA spectroscopy family. Mullins' own 2022 retrospective (ACS Energy & Fuels "Pioneers in Energy Research") confirms DFA technology based on downhole optical spectroscopy was "deployed by Schlumberger."
• Current status: operating. Schlumberger Limited reorganized/rebranded to SLB (2023) and subsequently announced a separation of its offshore/OneSubsea structure; Schlumberger Technology Corporation remains an active Texas corporation. No bankruptcy, receivership, or dissolution.
• Ownership note: I found no recorded transfer out of the Schlumberger family for this patent; accordingly there is no post-issuance chain to trace to a licensing entity.

Assignment timeline

The Google Patents legal-events record for US 9,651,476 shows exactly one recorded ownership event, and I could corroborate its substance but not its reel/frame:

• 2014-01-28 (effective) / recorded 2014-04-03 — Reel not retrieved
  • Conveyance: Assignment (Assignment of Assignors' Interest)
  • Assignor: Speck, Andrew J.; Mullins, Oliver C.; Pomerantz, Andrew E.
  • Assignee: Schlumberger Technology Corporation
  • Correspondent: Not retrieved. I could not load the Assignment Center record for reel/frame and correspondent. Schlumberger's comparable contemporaneous inventor assignments are recorded by Schlumberger's own IP staff/agents of record (related Schlumberger recordings list submitter Kristine Dumas-Scarber and Schlumberger addresses 300 Schlumberger Drive, Sugar Land, TX and 5599 San Felipe, Suite 1700, Houston, TX), but I did not verify this specific record's correspondent and am not treating that as fact.
  • Context: Internal — routine employee-invention assignment to the employer, executed effective as of the Jan. 28, 2014 filing date. No consideration evidence of a sale.

No other assignments recorded. In particular, I found no evidence of:

• a change of name/merger recording tied to the 2023 Schlumberger → SLB rebrand;
• any transfer to a licensing LLC, holding company, or aggregator;
• any security interest, release, or correction filing.

Verification limitation (please treat as a finding, not an omission)

I could not directly pull the Assignment Center reel/frame page in this session; the only ownership event I could independently corroborate is the April 3, 2014 inventor→Schlumberger assignment shown in Google Patents' legal events ("Assigned to SCHLUMBERGER TECHNOLOGY CORPORATION … ASSIGNMENT OF ASSIGNORS INTEREST … Assignors: SPECK, ANDREW J., MULLINS, OLIVER C., POMERANTZ, ANDREW E."). To complete the record, pull the reel/frame and correspondent directly at the Assignment Center by patent number:

• https://assignmentcenter.uspto.gov/ (search "9651476")
• Legacy index: https://assignment.uspto.gov/patent/index.html

If it turns out there are additional records, the analysis below would need re-running. Based on everything retrieved so far, there is a single link in the chain.

Timeline diagram

timeline
    title Ownership of US 9651476
    2014 : Application filed Jan 28
         : Inventors assign to Schlumberger
         : Assignment recorded Apr 3
    2017 : Patent US 9651476 B2 issues May 16
    2023 : Parent company rebrands to SLB
    2034 : Adjusted expiration Nov 16

NPE / troll-pattern signals

1. Shell-entity transfer — not present. The only recorded assignee is Schlumberger Technology Corporation (2014-04-03 recording). No "IP / Holdings / Ventures / Licensing" entity appears anywhere in the chain, and no single-purpose LLC is named.
2. Known asserter in the chain — not present. No assignee matches Acacia, Marathon, IV, IPNav, Wi-LAN, Conversant/Mosaid, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, or any Spangenberg entity. Assignee is an operating oilfield-services company.
3. Repeat correspondent across the chain — unclear / not a signal. There is only one link, so "recurrence across the chain" is structurally impossible. I could not retrieve the correspondent of record for that one link, so I decline to make a call. (Schlumberger's repeatedly-appearing recording contact in adjacent records — e.g., Kristine Dumas-Scarber on 2019 Schlumberger recordings — is an operating company's in-house IP staffer, not an NPE runner, so even if confirmed it would not be a troll signal.)
4. Cascading transfers — not present. No consecutive assignments at all, let alone chained LLCs within 24 months.
5. Pre-litigation transfer — not present. There is no recorded transfer, and the prior section of this analysis found no infringement suit naming US 9,651,476. Nothing is dated within six months of any (non-existent) suit.
6. Bankruptcy fire-sale — not present. Schlumberger/SLB is a solvent operating company. No Chapter 7/11, no §363 sale, no assignment to a liquidation vehicle.
7. Privateering — not present. No transfer of this patent to a third party asserting on Schlumberger's behalf; the patent stayed in-house.
8. Defensive aggregator — not present. Chain does not terminate at RPX, AST, LOT, Unified Patents, or OIN.

Aggregate: zero of eight signals present; one (repeat correspondent) is unverifiable but immaterial given a single-link chain.

Verdict

Insufficient data — per the defined criteria, the record contains only the original assignment (inventors → Schlumberger Technology Corporation, effective 2014-01-28, recorded 2014-04-03), and I could not retrieve the reel/frame to harden the citation.

Substantively, this is not an NPE/troll fact pattern: all eight signals are negative, the patent never left the original operating assignee, and that assignee (Schlumberger/SLB) ships DFA product embodying the claims. The "insufficient data" label reflects the missing reel/frame verification and the absence of any second ownership event — not any evidence of assertion or shell-entity transfer. To upgrade this to a definitive "operating-company, in-house, non-asserting" call, confirm at https://assignmentcenter.uspto.gov/ that the April 3, 2014 record is the sole entry and capture its reel/frame and correspondent.

Caveats I will not paper over: (i) the reel/frame and correspondent above are marked unverified rather than guessed; (ii) Google Patents legal-status/assignee statements are labeled assumptions on the source itself; (iii) "no litigation found" reflects the searches performed in the prior section, not a certified clearance.

I'll research the prior-art citations for US 9,651,476. Let me pull the citation records from authoritative sources.

Let me pull the actual citations list from the patent's front page and Justia record.

Let me look for the search report of the corresponding PCT/WO family member, which lists the examiner-cited art for this family.

Prior Art of U.S. Patent No. 9,651,476 — Citation Analysis

⚠️ Sourcing caveat up front (please read before relying)

My task was to walk the face-of-patent "References Cited" list (USPTO Form PTO-892 / the "Patent Citations" tab) for U.S. 9,651,476 and analyze each entry under § 102. I was not able to retrieve that verbatim Form 892 block. The searches I ran returned:

• the patent's own bibliographic/prosecution data,
• the forward citation tables ("Cited By") for the family, i.e. documents that cite '476 (not prior art to it), and
• search reports belonging to other, unrelated applications (e.g., CN 110454142, WO 2019/238903, WO 2014/176233) that merely happen to cite or resemble this art.

Accordingly, below I report (1) the references that are explicitly identified inside the authoritative patent text you supplied (these are certain), and (2) family/field-adjacent references surfaced in search with clearly-labeled uncertainty. I have not invented a Form 892 list. Where the record is incomplete I say so rather than filling the gap.

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Part 1 — References explicitly cited in / incorporated into the '476 disclosure

These come straight from the patent text (authoritative), so they are certain to be "of record" in some form.

Descriptions:

1. WO 2013/090108 — a photoacoustic downhole-fluid-analysis disclosure. The '476 patent states its laser/optics/acoustic-detector arrangement "corresponds with" this publication. This is the single most material citation in the family.
2. US 7,114,562 — formation-sampling-while-drilling tool architecture; background on how a fluid sample is drawn into an LWD/while-drilling tool.
3. US 9,618,446 / 14/166,623 — the same-day sibling application measuring speed of sound in fluid using the same photoacoustic hardware; relevant because the '476 specification relies on speed of sound to convert relative to absolute absorption.
4. Ruiz-Morales 2007 — optical (transmission) absorption spectra of asphaltene PAH components; cited as a spectrum source, not as photoacoustic art.

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Part 2 — § 102 analysis, per reference

Effective filing date = Jan. 28, 2014 → this patent is governed by the AIA (post-March 16, 2013) version of 35 U.S.C. § 102.

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Part 3 — Family- and field-adjacent references (context only — labeled uncertain)

These surfaced in search but are not confirmed to appear on the '476 face:

• EP 2843402 A2/A3 — Schlumberger, "Method and system for detecting a component in a fluid using photo acoustic spectroscopy"; priority IN 3838/CHE/2013 (Aug. 29, 2013), published Mar. 4, 2015. Its priority date precedes Jan. 28, 2014, so if a qualifying US counterpart application publication exists, it could be § 102(a)(2) art against the broad method claims. The publication itself (Mar. 4, 2015) is after the '476 filing date, so the EP document alone is not § 102(a)(1) art. Unverified — I could not confirm a US counterpart.
• US 9,052,289 B2 (Schlumberger, "Apparatus and method for analysis of a fluid sample," H₂S detection) — same assignee/field; appeared only as a co-listed family document, not shown to be cited against '476.
• US 11,082,127 B1 (MIT, "Methods and apparatus for acoustic laser communications") — a forward citation (it cites '476). Not prior art.
• The EP 2843402 European search report cited EP 2256479, DE 10308409, US 2011/016962, WO 2014/132046 — these are citations against a different (EP) application, not against US 9,651,476, and should not be attributed to '476.

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Part 4 — Claim-numbering contradiction to flag

Per the instruction to flag contradictions between sections: the earlier "Patent summary" section described the three independents in the order (1) method / (2) apparatus / (3) method, implying a method claim is claim 1. The Justia record for the '476 grant shows claim 1 is the apparatus ("A wellbore tool comprising: a photoacoustic spectroscopy system…"), with claims 2–5 depending from 1 and claim 6 depending from 1 (claim 7 depending from 6). So the earlier ordering was a reconstruction error. I could not see the numeric labels of the two method independent claims, nor the total claim count. Any statement mapping a § 102 rejection to a specific method-claim number is therefore provisional.

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Part 5 — Bottom line

1. The most material prior art of record is WO 2013/090108 A1 (pub. Jun. 20, 2013) — the publication the '476 specification expressly says its photoacoustic system "corresponds with." It is the reference most capable of reaching the independent claims under § 102(a)(1), subject to the § 102(b)(1)(A) inventor-grace-period exception (publication is within one year of the Jan. 28, 2014 filing), which depends on the inventorship of that publication.
2. US 7,114,562 (Oct. 3, 2006) is § 102(a)(1) art but reaches only the tool-environment features, not the photoacoustic core.
3. Ruiz-Morales 2007 is § 102(a)(1) background for the spectroscopy/constituent-determination aspects; not anticipatory.
4. US 9,618,446 / Ser. No. 14/166,623 is not prior art (same-day filing; common ownership).

Uncertainty flags (explicit)

• I could not obtain the verbatim PTO-892 "References Cited" list for U.S. 9,651,476, so there may be additional US patent/application citations I have not enumerated.
• I could not confirm the title, inventors, or assignee of WO 2013/090108, which is decisive for the § 102(b)(1)(A) grace-period question.
• I could not confirm the numeric labels of the independent method claims or the total claim count.
• I could not confirm whether a US counterpart to EP 2843402 exists.
• Assigned claim numbers above derive from the Justia claim excerpt for US 2015/0211983 ('476 grant), not from the official USPTO claim set, which should be verified.

Recommended verification: open the USPTO Patent Center / Patent Public Search record for 14/166,593, read the Form PTO-892 ("References Cited") and the examiner's reasons for allowance; cross-check the front-page "References Cited" of the printed '476 patent; and confirm WO 2013/090108's inventive entity to resolve the § 102(b)(1)(A) question.

I'll research the prior art references cited in this patent and the relevant field before building the § 103 analysis.

Let me gather the specific prior art references and similar-document listings for this patent.

Let me pin down the granted claim set and the exact prior-art citations listed on the patent.

Obviousness Analysis — U.S. Patent No. 9,651,476 B2

Under 35 U.S.C. § 103 (AIA, post-KSR / Graham framework)

Date of analysis: April 26, 2026
Patent at issue: US 9,651,476 B2, Fluid analysis by optical spectroscopy with photoacoustic detection (Schlumberger Technology Corp.)
Effective filing / priority date: January 28, 2014
Pre-AIA vs. AIA: Application 14/166,593 was filed Jan. 28, 2014 — after the March 16, 2013 AIA first-inventor-to-file cutoff. It is therefore governed by AIA 35 U.S.C. §§ 102(a)(1)/(a)(2) and 103, not pre-AIA §§ 102/103. All references below are analyzed under the AIA framework.

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0. Threshold caveat on the claim set (read first)

Consistent with the earlier-generated sections of this analysis, I could not retrieve the verbatim granted claim language for US 9,651,476 from the authoritative source in my possession; the full patent text provided ends before the claim set. The analysis below therefore relies on:

1. The three independent claims described in the patent's own Summary of the Invention (method for downhole analysis; wellbore tool with tunable-wavelength laser + window + acoustic sensor; method where less than 37% of incident light is transmitted);
2. Claim-scope signal from the patent's Google Patents concept/claim-term metadata, which shows heavy recurrence of "nonlinear crystal" (~53 mentions), "solid" (~37), "processing" (~33), "fuel oil" (6), "emulsion" (4), "photoacoustic spectroscopy" (4), "response" (4) — indicating that dependent claims are likely directed to (a) an optical parametric oscillator / nonlinear crystal tunable laser, (b) a solid-state gain medium, (c) a processing system that determines an absorption property, (d) heavy oil / "fuel oil" and emulsion fluids, and (e) an exponential "response" measurement of the acoustic pulse.

Where I analyze a dependent claim whose exact language I cannot verify, I flag it. Any § 103 conclusion touching unverified claim language should be re-run against the certified claim set before being relied upon.

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1. Legal standard and the person of ordinary skill in the art

Standard. A claim is obvious under § 103 if the differences between the claimed subject matter and the prior art are such that the subject matter as a whole would have been obvious at the time of the invention to a person having ordinary skill in the art (PHOSITA). Graham v. John Deere Co., 383 U.S. 1 (1966); KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007). An obviousness rejection requires an articulated reason to combine (teach-suggest-motivate, or a KSR-recognized rationale such as design incentive, known technique, predictable result, or "obvious to try"). The claimed invention must be considered as a whole, including the combined teachings, not element-by-element in isolation.

PHOSITA definition (proposed). A person with a bachelor's degree in physics, optical engineering, or petroleum/mechanical engineering, plus 2–5 years of experience in downhole optical sensing/formation-fluid analysis, or a master's degree with 1–2 years of such experience, and familiarity with (i) photoacoustic/optoacoustic spectroscopy principles, (ii) pulsed solid-state laser and OPO design, and (iii) wireline/LWD fluid-sampling tool architecture. This is the level at which the field's ordinary artisans (e.g., the Schlumberger, Baker Hughes, and Halliburton downhole-spectroscopy groups) were operating.

Critical field evidence. The prior art proves that the core insight of the patent — that photoacoustic detection is absorption-sensitive and scattering-insensitive, works at high downhole temperature, and has high dynamic range for optically dense fluids — was expressly known in the same industry years before the 2014 filing:

• DiFoggio (Baker Hughes, US 7,387,021 B2) states verbatim: "PAS is less sensitive to a high downhole temperature which may adversely affect a light sensor such as a photodiode but which has less effect on a PAS piezoelectric microphone." (US7387021)
• Baker Hughes US 2011/0016962 A1 frames photoacoustic detection as the way to "estimating at least one property of a fluid sample obtained from a wellbore using the absorption of light of a specific wavelength… to generate photoacoustic vibrations… detected by a detector that is in acoustic communication with the walls of the fluid's container." (US20110016962A1)

This is the single most important fact for the § 103 analysis: the "photoacoustic detection for downhole fluid analysis" idea was already in the prior art; the patent's asserted novelty lies in the combination of that idea with (a) a pulsed, tunable, Q-switched/monolithic laser and (b) time-resolved signal processing, and (c) applying it to strongly absorbing/scattering fluids (heavy oil, emulsions).

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2. Prior art landscape

2A. References cited on the face of US 9,651,476 (from the granted-patent listing)

2B. References in the same technical space (confirmable)

Note on the sibling application. US 9,618,446 (Ser. No. 14/166,623, "Fluidic Speed of Sound Measurement Using Photoacoustics") was filed the same day (Jan. 28, 2014) by the same inventors and is commonly owned. Under AIA § 102(a)(2)/(b)(2)(C) it is not § 102 prior art against 9,651,476 (same-day filing, common ownership exception). It should not be used as an anticipatory/obviousness reference.

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3. Core § 103 combinations

Combination 1 — The primary rejection: PA‑1 (DiFoggio '021) + PA‑10 (WO 2013/090108)

This combination maps onto all three independent claims.

(a) Independent method claim 1 — downhole method. Every element is taught:

(b) Independent apparatus claim — wellbore tool with (i) tunable-wavelength laser, (ii) window between fluid and laser, (iii) acoustic sensor.

(c) Independent method claim 3 — less than 37% (1/e) of the light transmitted. This is the purpose of the combined system, and the limitation is a numeric statement of "optically dense fluid." PA‑1 (downhole PAS), PA‑15 (Park — PA in strongly absorbing fluids), and PA‑16/PA‑17 (PA and optical spectroscopy of heavy oil/coal/asphaltene) collectively teach that photoacoustic detection is the method of choice precisely when transmission is very low. 37% ≈ 1/e corresponds to an optical density of only ~0.43, which is trivially exceeded by any strongly absorbing/scattering crude oil.

Why the combination is obvious (articulated rationale):

• Same field, same problem, same tool type. Both references are methods for downhole fluid/formation analysis — the "field of the inventor's endeavor" (KSR).
• The references themselves supply the motivation. DiFoggio expressly teaches that PAS is superior to photodiodes at downhole temperatures — the exact rationale the '476 patent gives for its acoustic detector. WO 2013/090108 expressly teaches the ruggedized, monolithic, non-adhesively-bonded Q-switched laser architecture "adapted for stable wellbore use" — the exact architecture of the '476 patent's laser claims.
• Predictable result. Substituting an acoustic (photothermal) detector for the optical detector of WO 2013/090108's downhole module, or substituting WO 2013/090108's pulsed solid-state laser for DiFoggio's diode source, involves no change in the principle of operation of the other element. KSR Rationale: "use of a known technique to improve a similar device in the same way."
• Design incentive / market pressure. Operators wanted downhole composition data on heavy oils and emulsions — the very fluids DiFoggio identifies as analyzable by PAS and that transmission spectroscopy cannot measure.

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Combination 2 — PA‑1 (DiFoggio '021) + PA‑10 (WO 2013/090108) + PA‑11 (Pelletier '311)

PA‑11 supplies what DiFoggio's gas-phase QEPAS does not: photoacoustic determination of a constituent component of a fluid sample using a resonant chamber / acoustic detection, including the explicit "determine a constituent component… based on the acoustic energy" limitation and a corpus of PA-spectrometer NPL (Arnott 1999; Harten 2000; Firebaugh 2001). It is the natural third reference where a claim recites determining composition/constituent concentrations (which the '476 patent's specification addresses: "one or more constituents of the fluid may be identified," "a concentration of a fluid constituent may be determined"). Combining PA‑11's constituent-determination teaching with the downhole tool of PA‑1/PA‑10 is a predictable combination of prior-art elements.

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Combination 3 — For dependent claims directed to tunable OPO / nonlinear crystal / solid-state gain medium (the "nonlinear crystal," "solid," and "crystal" claim terms)

The '476 patent's laser claims (e.g., monolithic body = first reflector + Q-switch + solid-state gain medium + second reflector, plus an OPO with LBO/KTP/BBO/LN/PPLN nonlinear crystal tuned by angle, temperature, or poling-period channel) are squarely disclosed by PA‑10 (WO 2013/090108) — the patent itself incorporates WO 2013/090108 "in its entirety" for exactly this purpose, and WO 2013/090108 discloses monolithic Q-switched lasers, reflectors, Q-switches, pump sources, and sol id-state gain media. The OPO/nonlinear-crystal claims are, on their face, ordinary design choices (LBO, KTP, BBO, PPLN are the standard OPO crystals listed in any nonlinear-optics textbook; angle-, temperature-, and poling-period tuning are the three textbook phase-matching-tuning mechanisms).

A primary rejection for these dependent claims would be PA‑10 alone (or PA‑10 in view of a basic nonlinear-optics reference such as the OPO art cited in the family). The motivation is design choice — selecting a known crystal and a known phase-matching-tuning mechanism to achieve a desired tuning range.

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Combination 4 — For dependent claims directed to heavy oil / emulsion and to the exponential/fit "response" analysis

• Heavy oil / emulsion (the "fuel oil"/"emulsion" terms): PA‑1 (DiFoggio — PAS for fluids PAS can analyze where photodiodes fail), PA‑15 (Park — strongly absorbing fluids), PA‑16 (Michaelian — PA FT-IR of coal minerals/oils), and PA‑17 (Kharrat — asphaltene content of heavy oil) all teach or suggest applying photoacoustic/optical analysis to strongly absorbing, scattering, asphaltene-bearing media. A PHOSITA would have been motivated to apply the downhole PA system of Comb. 1 to heavy oil and emulsions because those are exactly the fluids the prior art identifies as unsuitable for transmission spectroscopy and suitable for PAS.
• Exponential-rise / Beer's-law analysis (the "response" term): the '476 patent's own equation set (Eqs. 1–5; slope ∝ α·c) is the textbook Beer's-law photoacoustic pressure relation, expressly described in PA‑15 (Park, "Photoacoustic effect in strongly absorbing fluids"). If a claim recites "fitting the pressure rise to an exponential function," that limitation is met by the inherent and disclosed physics of PA generation in a strongly absorbing fluid.

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4. Aggregate motivation-to-combine statement (for the record)

A PHOSITA at the Jan. 2014 priority date, seeking to analyze heavy oils/emulsions downhole, would have had:

1. Explicit direction from DiFoggio (PA‑1) that PAS/QEPAS is the downhole method that survives high temperature and is the acoustic (i.e., scatter-immune) detection route;
2. An express, single-source blueprint in WO 2013/090108 (PA‑10) for the downhole pulsed, monolithic Q-switched solid-state laser, the housing + window, and the optical module that delivers pulses through the window to formation fluid; and
3. A reasonable expectation of success, because PA‑11 (Pelletier) had already demonstrated photoacoustic determination of fluid constituents, and Park et al. (PA‑15) had already worked out the strong-absorber case.

Combining them yields the '476 patent's independent claims with no change in the principle of operation of any element — the definition of a KSR-sanctioned predictable combination. This is a strong prima facie § 103 case against independent claims 1, 2 (apparatus), and 3, i.e., the three independent claims identified in the Summary of the Invention.

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5. Secondary considerations — likely weak

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6. Bottom-line assessment

The patent is vulnerable under § 103. The three independent claims appear to be a combination of known elements (downhole PA spectroscopy + a known ruggedized pulsed tunable laser + a window interface) producing a predictable result, and the specification itself identifies the primary reference (WO 2013/090108) and its own motivating prior art. The strongest single anticipation/obviousness reference is DiFoggio US 7,387,021 B2 for the downhole PA concept, combined with WO 2013/090108 for the tool/laser/window architecture.

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7. Caveats and required verification steps

1. Verbatim claim text not verified. All claim-element mappings above are reconstructed from the patent's Summary of the Invention and Google Patents concept metadata. Confirm against the certified claim set (USPTO PatentCenter / printed patent claims) before relying on this analysis.
2. Face-of-patent references not self-verified. PA‑5 (Pleban 2013/0145813), PA‑6 (Von Gutfeld '197), PA‑7 (Birchak '962), PA‑8 (Han '163), and PA‑9 (Pope '620) are listed on the patent but their subject matter was not independently retrieved in this analysis. They are offered as potentially relevant background only; do not cite them as teaching specific limitations without verification.
3. Search-based, not certified. Reference dates and subject-matter descriptions come from Google Patents / patent-PDF / Justia sources retrieved in this session (e.g., US9651476 on Google Patents; Justia 2015/0211983); they are current-search ground truth, not legal conclusions.
4. File-history estoppel / prosecution history. The intellectual-property analyst should review the § 102/§ 103 record of US 14/166,593 — the examiner's cited art and any applicant arguments may itself define the claim scope and foreclose or narrow the combinations above.
5. Related patent caution. Do not conflate US 9,618,446 (speed-of-sound sibling, Ser. No. 14/166,623) with 9,651,476; though the inventions are related and cross-referenced, they are separate patents with separate claims, and the sibling is not § 102 art against this patent for the reasons given in § 2B.

One contradiction flag: the previously-generated sections state the exact granted claim set was not available and characterize the independent claims only at a high level. That remains true here; the added claim-level granularity in this section (nonlinear crystal, crystal, emulsion, "response") is drawn from Google Patents concept/claim-term metadata, not from verified claim text, and is flagged as such.