Zonal Isolation Patents: Who Leads, Where the Gaps Are 2026
- 86.4% concentration. The top five assignees alone account for 2,008 of the 2,325 records in scope — a field with almost no middle tier between the leaders and a long tail.
- Filing eased, not stopped. Annual filings fell from 51 in 2021 to 35 in 2024, a 31% pullback, after a 2022 peak of 106 — the most recent complete years still show steady output, not withdrawal.
- Chemistry outweighs hardware. C09K cement/fluid materials claims touch 62.1% of records and E21B drilling-well claims 55.7%, while sensing and data classes (G01N, G01V, G06K) each sit under 5% — evaluation and monitoring remain comparatively open.
Filing growth compares 2021 (51 records) with 2024 (35) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 2,325 records in scope (CR5), not by the ranked leaders only.
What this field covers
Zonal isolation and cement evaluation patents cover the methods and materials used to confirm and maintain a hydraulic seal between a wellbore and the surrounding formation: cement bond logging, ultrasonic and sonic-attenuation imaging, microannulus detection, squeeze cementing and the cement chemistry that resists sustained casing pressure over the life of a well. It sits at the intersection of oilfield chemistry (C09K, C04B) and downhole measurement and drilling practice (E21B), which is why the two largest IPC subclasses in this dataset are materials-facing rather than sensor-facing.
The dataset in scope spans 2,325 published records filed between 2015 and mid-2026, drawn from cement and completion-services filings across major receiving offices including the United States, WIPO/PCT, Canada, Australia, the United Kingdom and the EPO.
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Filing trend and technology composition
Two views of the same 2,325 records: how filing volume has moved year over year, and which IPC subclasses carry the claim weight. Because a single record can carry several IPC codes, the composition shares sum to well over 100%.
Filing trend, 2017–2026
Annual filings rose from 101 in 2017 to a peak of 106 in 2022, then eased to 35 by 2024 — a complete-year decline of 31% from the 2021 level of 51. 2025 and 2026 counts are still filling in as publication catches up with filing, so they should not be read as a continued drop.
IPC subclass composition
C09K (materials for miscellaneous applications, including cement and treatment fluids) touches 62.1% of the 2,325 records, and E21B (earth and rock drilling) touches 55.7%. C04B (cement and ceramics) sits at 44.4%. Evaluation- and data-facing classes — G01N material testing, G01V geophysics, G06K data recognition — each cover under 5% of records, marking where instrumentation and analytics claims are comparatively thin against the chemistry and mechanical base.
Shares are the percentage of the 2,325 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Zonal Isolation and Cement Evaluation with Eureka
This page is one run against one query. Ask Eureka your own question about zonal isolation and cement evaluation and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative filing and most-cited prior art
Apparatus and methods for through-casing remedial zonal isolation (WO2010046020A1)
This invention relates to a method of achieving hydraulic zonal isolation by use of a deployable isolation assembly and zonal isolation drilling tool. The assembly is lowered downhole to the region where hydraulic seal loss has occurred; the tool drills into the formation layer, pumps zonal isolation fluid and plugs the hole in a single trip, with evaluation of isolation and job progress performed as part of the same operation.Filed by Services Petroliers Schlumberger; published 2010-04-29.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5346012A | Fine particle size cement compositions and methods | 408 |
| 2 | US5125455A | Primary cementing | 366 |
| 3 | US5121795A | Squeeze cementing | 358 |
| 4 | US5127473A | Repair of microannuli and cement sheath | 320 |
| 5 | US5123487A | Repairing leaks in casings | 301 |
| 6 | US8316936B2 | Use of micro-electro-mechanical systems (MEMS) in well treatments | 259 |
| 7 | US6230804B1 | Stress resistant cement compositions and methods for using same | 254 |
| 8 | US5464060A | Universal fluids for drilling and cementing wells | 246 |
| 9 | US6832652B1 | Ultra low density cementitious slurries for use in cementing of oil and gas wells | 228 |
| 10 | US5086850A | Well bore drilling direction changing method | 219 |
Citation counts favour older filings simply because they have had longer to be cited; treat them as a signal of influence within this corpus, not of current commercial importance.
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The concentration and composition figures point to a field where the chemistry base is heavily claimed but evaluation and remedial methods leave more room.
The field has almost no middle tier
Five assignees hold 2,008 of the 2,325 records in scope, and the top ten reach 96.6%. New entrants are filing into a field where the leading names have already staked out primary cementing, squeeze cementing and microannulus repair — the most-cited records in this dataset are exactly those foundational method claims.
Cement and fluid chemistry carries the claim weight
C09K and C04B together cover most of the corpus, meaning the composition of cement slurries, spacer fluids and additive systems is the most densely claimed layer. Mechanical isolation hardware under E21B is nearly as dense, at 55.7% of records.
Sensing and data analysis are comparatively open
Material testing (G01N, 4.1%), geophysical survey (G01V, 3.7%) and data recognition (G06K, 2.1%) each cover a small share of records relative to the chemistry and drilling classes. That gap is where cement-evaluation logic — ultrasonic imaging interpretation, sonic-attenuation processing, automated bond-log classification — sits furthest from saturation.
A cooling but not a collapsing filing pace
Filings fell from 51 in 2021 to 35 in 2024, following a 2022 peak of 106. Recent-year momentum data show the largest assignees filing fewer new records in the latest tracked year, but the base of claims already granted means the barrier to entry has not fallen with it.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to zonal isolation and cement evaluation, with the prior art for and against each one.
Who holds the field, and where the gate sits
The ranking covers 100 companies counted by patent family; it is the full list the dataset returns, not a curated top tier. Momentum in the most recent tracked year has slowed across the largest names, even as their cumulative share stays dominant.
One name sets the baseline
The leading assignee alone holds 1,630 of the 2,325 records in scope — far ahead of fifth place at 77 and tenth place at 35. Co-assignee pairings within this group appear repeatedly, reflecting how filings are split and re-assigned across related corporate entities rather than genuinely independent competitors.
A sharp drop after the leaders
By tenth place the count is down to 35 records, a fraction of the leader's total. This shape — one dominant filer, a handful of mid-size competitors, then a long tail of smaller and single-filing entrants — is typical of a field defined early by a few large service companies.
Momentum has cooled at the top
Several of the largest assignees show sharply reduced or zero filings in the latest tracked year, with year-on-year changes ranging from flat to -100%. Given the roughly 18-month publication lag, this likely overstates any real slowdown, but it does suggest the largest filers are not currently expanding their claim base at the pace seen earlier in the period.
| Assignee | Recent year | YoY |
|---|---|---|
| Saudi Arabian Oil Co (Saudi Aramco) | 3 | 0% |
| Halliburton Energy Services, Inc. | 2 | -67% |
| Schlumberger Technology B.V. | 0 | -100% |
| Schlumberger Technology Corp. | 0 | -100% |
| Schlumberger Holdings Ltd. | 0 | -100% |
| Schlumberger Holdings Ltd. | 0 | — |
| Schlumberger Canada Ltd. | 0 | -100% |
| Prad Research & Development Ltd. | 0 | — |
Where to take this next
The dataset points to specific next steps depending on whether the goal is freedom-to-operate, portfolio positioning or identifying an open filing angle.
Check freedom-to-operate against the leader's portfolio
With one assignee holding 1,630 of 2,325 records, any new filing in core cementing methods should be checked against that portfolio first, not against the field average.
Explore assignee portfolios in EurekaLook at evaluation and data classes for filing angles
G01N, G01V and G06K each cover under 5% of records — a first claim built around automated interpretation of bond-log or ultrasonic data has more room than one built around cement chemistry.
Run a white-space search in EurekaTrack the most-cited prior art before drafting
The most-cited records in this dataset are decades-old foundational method claims on primary and squeeze cementing; understanding what they actually cover shapes how a new claim should be scoped.
Review cited prior art in EurekaCommon questions on this landscape
One assignee dominates this dataset, holding 1,630 of the 2,325 records in scope, far ahead of the next four combined. The top five assignees together account for 86.4% of all records, and the top ten reach 96.6%, leaving very little share for the remaining ranked companies. This concentration reflects how the field grew around a small number of large oilfield service companies rather than a broad base of independent inventors.
Filings peaked at 106 in 2022 and had fallen to 35 by 2024, a 31% decline from the 2021 level of 51. That said, 2025 and 2026 figures are still incomplete because publication typically lags filing by about 18 months, so the most recent years understate real activity. Based on the last fully comparable years, filing volume has cooled from its 2022 high rather than stopped.
Cement and treatment-fluid chemistry (IPC class C09K) appears in 62.1% of the 2,325 records, and earth and rock drilling methods (E21B) in 55.7%, making these the densest claim areas. Cement and ceramics materials (C04B) follow at 44.4%. By contrast, classes tied to sensing, geophysical analysis and data processing each cover under 5% of records, indicating that the evaluation and monitoring side of the field carries far less claim density than the chemistry and hardware side.
The clearest gaps sit in evaluation and analysis: material testing (G01N), geophysical survey (G01V) and data recognition (G06K) each cover only a small share of the 2,325 records, well below the chemistry and drilling classes. Practically, that points to automated interpretation of cement bond logs, sonic-attenuation signal processing and sensor-based microannulus detection as areas where fewer prior claims stand in the way of a new filing. This should be read as thinner coverage, not an absence of any prior art.
WO2010046020A1, filed by Services Petroliers Schlumberger and published in 2010, covers a through-casing remedial method: a deployable isolation assembly and drilling tool lowered to the point of hydraulic seal loss, which drills into the formation, pumps isolation fluid and plugs the hole in a single trip, with isolation evaluation built into the same job. It is a combined mechanical-and-fluid remedial method claim rather than a materials or sensing claim, so it primarily constrains single-trip remedial isolation tooling and workflow rather than cement chemistry or bond-log interpretation.
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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.
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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.