Special Core Analysis Patents: Who Leads, Where the Gaps Are 2026
- Top 5 assignees hold 49.6% of all 258 records in scope — concentration sits at the very top, not spread across the ranked field of 69 companies.
- Filing peaked in 2018 at 31 records and the leading assignees show 0 filings in the latest year, though publication lag of roughly 18 months understates the most recent period.
- G01V and G01N together cover most records (42.2% and 41.1% of 258 records respectively) while AI-adjacent classes G06N and G06T sit under 10% — a sign of where digital methods have not yet been claimed hard.
Top-5 share is the combined record count of the five largest assignees divided by all 258 records in scope (CR5), not by the ranked leaders only.
What this dataset covers
This landscape draws on 258 published records matched against special core analysis and relative permeability measurement techniques — steady-state and centrifuge displacement, wettability index determination, residual oil saturation, capillary end effect and spontaneous imbibition — filed or published between 2015 and mid-2026. The scope is deliberately narrow: it captures the laboratory and instrumentation methods used to characterise multiphase flow in reservoir rock, not reservoir simulation or drilling more broadly.
Records were pulled from receiving offices led by the United States (109), followed by WIPO's PCT route (42), the EPO (36) and Canada (22), with smaller counts at AT and NO. That spread points to a field where applicants file first at home and route a meaningful share through PCT and EPO for wider coverage, consistent with an oilfield services and national-oil-company applicant base operating across jurisdictions.
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Filing trend and technology composition
Two views of the same 258 records: how filing activity has moved year on year, and which IPC subclasses the records fall into.
Filing trend, 2017–2026
Filings rose from 13 in 2017 to a peak of 31 in 2018, the highest point in the series. The count for 2026 (1 record) is a partial year and, together with the trailing years, is understated by the roughly 18-month gap between filing and publication — the ranked leaders all show zero filings in the latest year, which reads more as a publication-lag artefact than a real stop in activity.
IPC subclass composition
G01V (geophysics and gravity surveying) and G01N (material analysis and testing) each cover over 40% of the 258 records, with E21B (earth and rock drilling) close behind at 31.4%. Digital and AI-adjacent classes — G06F, G01R, G06N, G06T — sit well below that, with G06N (AI-based computing) at 7.0% and G06T (image processing) at 4.3%. Because a single record can carry several IPC classes, these shares add up to more than 100% and should be read against the 258-record total, not against each other.
Shares are the percentage of the 258 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Special Core Analysis and Relative Permeability with Eureka
This page is one run against one query. Ask Eureka your own question about special core analysis and relative permeability and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records and a representative filing
US20120241149A1 — Method for measuring rock wettability
A method of comparing a secondary oil recovery process with a tertiary oil recovery process, both applied to a substantially fluid-saturated porous medium containing an oil phase and an aqueous phase, using relaxation time measurements to calculate a wettability index modification factor for the oil phase or the aqueous phase, thereby comparing the tertiary process with the secondary process.Filed by BP Exploration Operating Company Limited, published 2012-09-27 — illustrates how wettability index measurement claims are framed around comparative recovery-process evaluation rather than the raw measurement step alone.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US4728892A | NMR imaging of materials | 414 |
| 2 | US4987368A | Nuclear magnetism logging tool using high-temperature superconducting squid detectors | 380 |
| 3 | US5493226A | Method and apparatus for measuring properties of core samples including heating and pressurizing the core sam… | 140 |
| 4 | US20110198078A1 | Formation evaluation instrument and method | 113 |
| 5 | US20170030819A1 | Processes and Systems for Characterizing and Optimizing Fracturing Fluids | 96 |
| 6 | US20160040514A1 | Reservoir Characterization and Hydraulic Fracture Evaluation | 80 |
| 7 | US5679885A | Process and device for measuring physical parameters of porous fluid wet samples | 78 |
| 8 | US20190087939A1 | Inferring petrophysical properties of hydrocarbon reservoirs using a neural network | 73 |
| 9 | US20120241149A1 | Method for measuring rock wettability | 73 |
| 10 | US6178807B1 | Method for laboratory measurement of capillary pressure in reservoir rock | 69 |
Citation counts inside this corpus favour older filings and should be read as a signal of influence, not of current technical relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers mean for a filing decision
Three read-outs from the concentration, class and citation data that matter for deciding where to file and where to watch.
Filing is concentrated at the very top
Half of all 258 records in scope sit with just five assignees, while the ranked field runs to 69 companies. That gap between the top 5 and the long tail means most of the ranked list holds only one or two filings each — the real competitive contest is among a handful of players, not across the full ranking.
Geophysics and material-testing classes dominate
G01V and G01N each cover more than four in ten of the 258 records, with E21B (wells) not far behind at 31.4%. Digital-processing classes — G06F, G01R, G06N, G06T — are present but each under 12%, which suggests the core measurement methods are far more heavily claimed than the software and AI layers built on top of them.
Foundational NMR patents still anchor citation counts
The most-cited records in this set are NMR-based measurement patents from the late 1980s and early 1990s, cited hundreds of times each within this corpus. That reflects the age advantage older filings get in citation counts inside a searched corpus, not that NMR core-analysis instrumentation is where current filing activity is concentrated.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to special core analysis and relative permeability, with the prior art for and against each one.
Who is filing, and where the field is still open
Filing activity concentrates around a small set of oilfield-services and national-oil-company applicants, with co-assignee links pointing to internal corporate structure rather than cross-company collaboration.
One applicant sits well clear of the field
The leading assignee holds 37 records against 19 for the fifth-placed company and 12 for tenth place — a steep drop-off that marks this as a field led by a small number of large, well-resourced filers rather than a broad base of specialist entrants.
Co-assignee links trace internal corporate groups
The strongest co-assignee pairings link entities under the same corporate umbrella rather than separate companies collaborating. That pattern is typical of large multinational filers routing the same invention through multiple subsidiary or regional entities for jurisdictional coverage.
Leading assignees show no filings in the most recent year
Several of the top-ranked assignees show zero filings in the latest year captured, including the sector leader. Given the roughly 18-month publication lag, this reads as an artefact of recent filings not yet appearing in the record rather than a genuine pullback — but it is a reminder not to read the most recent year as a trend signal.
| Assignee | Recent year | YoY |
|---|---|---|
| Saudi Arabian Oil Co | 0 | -100% |
| BP Exploration Operating Company Limited | 0 | — |
| Schlumberger Technology Corporation | 0 | — |
| Schlumberger Technology BV | 0 | — |
| IFP Energies Nouvelles | 0 | — |
| Services Petroliers Schlumberger SA | 0 | — |
| Schlumberger Canada Limited | 0 | — |
| Baker Hughes Holdings LLC | 0 | — |
Where to take this next
The dataset points to where claim space is dense and where it is not — the next step is testing a specific filing or freedom-to-operate question against it.
Map a specific claim against the leaders' portfolios
If a filing concept touches wettability index or capillary end effect measurement, check it against the top 5 assignees' claim scope first — they hold roughly half of all 258 records in scope.
Explore assignee portfolios in EurekaWatch the AI-adjacent classes for movement
G06N and G06T sit under 10% of records today; a new filing surge there would be an early signal worth tracking rather than reacting to after the fact.
Set up tracking in EurekaFrequently asked questions
Special core analysis (SCAL) covers laboratory measurements that go beyond routine porosity and permeability testing to characterise multiphase flow behaviour in reservoir rock, including relative permeability, capillary pressure curves, wettability index and residual oil saturation. It typically uses steady-state or centrifuge displacement methods, or spontaneous imbibition, to model how oil, gas and water move through the same rock sample under reservoir-like conditions. Routine core analysis, by contrast, measures single-phase properties like porosity and absolute permeability and is far less time- and cost-intensive. Patent filings in the SCAL space concentrate on measurement apparatus, test protocols and the software used to interpret the resulting curves.
Filing activity in this dataset is concentrated: the top 5 assignees together hold 49.6% of all 258 records in scope, and the top 10 hold 75.6%. The single leading assignee holds 37 records, well ahead of the fifth-placed company at 19 and tenth place at 12. This points to a field dominated by a handful of large oilfield-services and national-oil-company filers rather than a broad base of small specialist entrants, though the ranked list runs to 69 companies in total.
Publication typically lags the actual filing date by around 18 months, so any year close to the data cut-off will always show fewer records than were actually filed. In this dataset the 2026 figure is a single partial-year record, and several leading assignees show zero filings in the latest tracked year — that is a publication-lag effect, not evidence that activity in the field has stopped. The more reliable read is the completed-year trend, which peaked in 2018 at 31 records.
The IPC composition shows core measurement classes — G01V and G01N — each covering more than 40% of the 258 records, while AI-adjacent classes such as G06N (AI-based computing) and G06T (image processing) sit under 10%. That gap suggests digital interpretation layers built on top of established measurement hardware, such as automated capillary pressure curve fitting or image-based wettability scoring, are comparatively under-claimed relative to the underlying measurement methods themselves.
US20120241149A1, held by BP Exploration Operating Company Limited, claims a method of comparing secondary and tertiary oil recovery processes using relaxation time measurements to calculate a wettability index modification factor. It is narrow in scope: it covers the comparative recovery-process framing built on relaxation-time-derived wettability data, not wettability measurement generally. A new filing that measures wettability by a different physical method, or that does not frame the result as a secondary-versus-tertiary recovery comparison, would sit outside its specific claim language, though a freedom-to-operate review should check the full claim set rather than the abstract alone.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.