CO2-EOR Patent Landscape 2026 — PatSnap Eureka
CO2 Injection Enhanced Oil Recovery 2026
CO2-EOR has gained renewed strategic importance as operators simultaneously address declining reservoir productivity and mounting carbon sequestration obligations. This dataset spans foundational field operations through the most recent filings in 2025.
How CO2 Injection Transforms Oil Recovery and Carbon Storage
CO2-EOR exploits CO2’s ability to dissolve in crude oil, reduce oil viscosity and density, lower interfacial tension, and achieve miscible or near-miscible displacement at reservoir conditions — recovering oil that primary and secondary waterflooding methods leave behind. The field spans at least six identifiable sub-domains within this dataset, from continuous flooding to integrated CCUS-EOR architectures.
Field-scale evidence indicates that miscible CO2 flooding can increase recovery by 5–15 percentage points over waterflooding alone. As of 2011, the Weyburn-Midale project in Saskatchewan, Canada had stored approximately 18 megatonnes of CO2, while the US was already operating over 13,000 CO2-EOR wells and producing over 245,000 barrels per day via CO2-EOR.
The innovation timeline reveals three distinct phases: a foundational phase (2000–2011) establishing technical and economic baselines; a development and diversification phase (2012–2020) expanding into offshore, WAG, and modified CO2 chemistry; and an unconventional and integration phase (2021–2025) pivoting toward tight oil, shale, and multi-resource architectures combining CO2-EOR with geothermal and CCUS.
CO2 utilization rates documented in this dataset range from 167 to 227 standard cubic metres of CO2 per stock-tank barrel of oil recovered, and approximately 60% of injected CO2 can be retained at breakthrough if reinjection is not applied. Machine learning proxy models applied to CO2-assisted gravity drainage in the Rumaila oilfield achieved a simulated cumulative production gain of 416 MMSTB over a 10-year horizon.
Filing Trends, Jurisdiction Breakdown, and Technology Cluster Distribution
Within this dataset, patent filings cluster strongly around offshore recycling systems and thickened CO2 chemistry, with jurisdiction concentration in the US, Australia, and China. The most recent filings (2025) originate from Australia (Equinor divisionals) and China (Chengdu University of Technology), reflecting divergent global IP strategies.
Patent Documents by Jurisdiction — CO2-EOR Dataset
The US dominates with approximately 12 documents, followed by Australia with 5 Equinor divisional filings, reflecting both the largest active CO2-EOR market and a deliberate multi-jurisdiction protection strategy.
↗ Click bars to explorePatent Filings by Technology Cluster — CO2-EOR Dataset
Offshore CO2 recycling systems (Equinor family) account for the largest single cluster, while thickened/modified CO2 chemistry and integrated CCUS-EOR are the fastest-growing clusters based on 2021–2025 filings.
↗ Click bars to exploreCO2-EOR Deployment Zones: From Permian Basin to Pre-Salt Brazil
CO2-EOR is deployed across five distinct reservoir types in this dataset, each with unique engineering challenges and documented performance metrics. The following sites and domains represent the most evidenced deployments from field programs and simulation studies.
Weyburn-Midale, Saskatchewan, Canada
CO2 injection began at Weyburn-Midale in October 2000, and approximately 18 megatonnes of CO2 had been stored by 2011, making it the world’s largest monitored CO2 geological storage site at that time. The IEA GHG Weyburn-Midale CO2 Monitoring and Storage Project tracked reservoir performance across a full decade of injection into carbonate reservoirs. The site established the technical and economic baseline for miscible CO2 flooding in conventional onshore reservoirs.
Conventional OnshoreLiuhua Oilfield, Offshore Guangdong, China
Simulation of immiscible water-alternating-CO2 flooding across 16 WAG scenarios at the Liuhua oilfield offshore Guangdong showed that optimal WAG ratios below 1:2 achieved ultimate oil recovery factors of 24%, with CO2 storage efficiency exceeding 84%. This study (2020) represents a key offshore WAG optimization data point in the dataset. The Liuhua case demonstrates WAG’s ability to suppress CO2 fingering in offshore carbonate settings.
Offshore WAGOrdos Basin, China — Tight Oil
Feasibility studies in Ordos Basin tight oil (2023) used slim-tube and long-core displacement experiments to define near-miscible pressure ranges and optimal well pattern designs for advanced CO2 injection. CO2 pre-injection fracturing experiments on continental shale oil reservoirs in this dataset achieved an average oil recovery factor of 39.27% over seven soaking cycles — a relative increase of 31.6% over conventional huff-and-puff. CO2 diffusion into the tight matrix is identified as the dominant recovery mechanism when convective flow is limited.
Tight/UnconventionalBrazil Pre-Salt Carbonate Reservoirs
Brazil’s pre-salt carbonate reservoirs represent the only operational offshore CO2-EOR project cited in this dataset, documented in a 2021 study on the first steps of CO2 geosequestration in the pre-salt. Petrobras filed a novel US patent in March 2025 introducing saline rock caverns as control-volume buffers within WAG injection loops, enabling simultaneous EOR and CCUS using existing oil field infrastructure. The Petrobras PROCLIMA/CENPES program underpins this long-standing offshore CCUS commitment.
Offshore CCUS-EORKey Patent Assignees Driving CO2-EOR Innovation
Patent assignees in this dataset are limited in number but strongly differentiated by geography and technical focus. Equinor Energy AS holds the largest single family with 9+ documents spanning six jurisdictions, while Saudi Arabian Oil Company, Petrobras, ConocoPhillips, and Chengdu University of Technology each occupy distinct technical niches.
Patent Document Count by Assignee — CO2-EOR Dataset
↗ Click bars to exploreEquinor Energy AS
Equinor Energy AS (originally filing as Statoil Petroleum AS) is the most prolific patent assignee in this dataset, with at least 9 active or pending patent documents spanning US, GB, AU, WO, NO, and CA jurisdictions — all derived from a single GB priority application filed February 7, 2017. The family covers back-produced CO2 recycling systems for offshore CO2-EOR, with the most recent AU divisional filed in May 2025 (active). The core innovation claims that the complete gas phase (CO2 plus hydrocarbons) can be reinjected without prior separation, simplifying offshore processing substantially.
NorwaySaudi Arabian Oil Company
Saudi Arabian Oil Company holds at least 4 documents in this dataset — two US active patents (2023, 2024) and one WO filing (2023) — all directed at thickened CO2 gravity drainage injection processes. The 2024 US patent claims novel CO2 thickeners that dissolve in dense CO2 at diluted concentrations, increase CO2 viscosity to match oil mobility, and avoid environmental concerns of fluorinated predecessors. A separate 2024 US patent covers using CO2 storage in structural lows to enhance reservoir drive mechanisms in carbonate architectures where gravity drainage dominates.
Saudi ArabiaFive Frontier Signals Shaping CO2-EOR Through 2026
Based on the most recent filings and publications in this dataset (2022–2025), five directional signals are apparent — ranging from multi-resource geothermal integration to machine learning-driven injection optimization and novel CO2 storage media.
Multi-Resource Integration: CO2-EOR + Geothermal + Shale Oil
The most recent CN patents from Chengdu University of Technology (filed February and July 2025) describe closed-loop systems where CO2 simultaneously serves as the EOR injectant in shale oil formations and as the working fluid for heat extraction from dry hot rock geothermal resources. CO2 injected for EOR is envisioned cycling through the geothermal loop, generating power before reinjection. This represents a convergence of three previously distinct technology domains into a single integrated patent-protected architecture.
Machine Learning Optimization of WAG Injection Parameters
Publications from 2022 document growing use of machine learning — including random forest regression across 216 CMG-simulated scenarios and reduced-physics proxy models — to replace computationally expensive full-physics reservoir simulation in optimizing CO2-WAG injection parameters, slug sizes, WAG ratios, and production well schedules. Machine learning proxy models applied to CO2-assisted gravity drainage in the Rumaila oilfield achieved a simulated cumulative production gain of 416 MMSTB over a 10-year horizon. This trend is consistent with broader upstream digitalization and represents a growing research cluster.
Continuous CO2 Flooding vs. Water-Alternating-Gas (WAG) Injection
Click any row to explore further.
| Dimension | Continuous CO2 Flooding | Water-Alternating-Gas (WAG) |
|---|---|---|
| Primary Mechanism | Miscible or immiscible displacement; CO2 dissolves in oil, reduces viscosity and IFT, vaporizes intermediates | Alternating CO2 and brine slugs to improve areal and vertical sweep efficiency; suppresses CO2 fingering |
| Recovery Factor | 5–15 percentage point increase over waterflooding; ~60% CO2 retained at breakthrough without reinjection | Liuhua oilfield WAG ratios below 1:2 achieved ultimate oil recovery factors of 24%; 84%+ CO2 storage efficiency |
| CO2 Utilization Rate | 167–227 standard cubic metres CO2 per stock-tank barrel documented in dataset | Quantified via random forest regression across 216 CMG-simulated WAG scenarios (2022 study) |
| Key Challenge | CO2 mobility control — low viscosity causes channeling and early breakthrough in heterogeneous reservoirs | Operational complexity of alternating injection; WAG ratio and slug size optimization required per reservoir |
| Key Reservoir Type | Conventional onshore carbonates and sandstones; Weyburn-Midale, Shengli, Jilin, Permian Basin documented | Offshore carbonates (Liuhua, Guangdong); conventional reservoirs with sweep efficiency challenges |
| Optimization Approach | Reduced-physics proxy models and ML applied to Rumaila oilfield; 416 MMSTB simulated 10-year production gain | Multi-phase strategy: WAG → shut-in → CO2-over-water → final storage protocol proposed in 2023 literature |
| CO2 Storage Co-benefit | ~60% CO2 trapped at breakthrough; Weyburn-Midale stored 18 Mt by 2011 | Liuhua scenarios: 84%+ CO2 storage efficiency at optimal WAG ratios below 1:2 |
| Offshore Applicability | Limited by CO2 supply logistics; Equinor back-produced CO2 recycling system addresses this | Evaluated offshore at Liuhua (Guangdong, China); 16 WAG scenarios simulated in 2020 study |
Frequently Asked Questions: CO2-EOR Technology and Patents
MMP is the critical design parameter for miscible CO2 flooding — it is the minimum pressure at which CO2 achieves miscibility with crude oil through a multiple-contact process. Operating above MMP enables CO2 to dissolve in oil, reduce viscosity and density, lower interfacial tension, and vaporize intermediate hydrocarbons, maximizing displacement efficiency. The dataset shows that chemical additives can reduce MMP significantly: polymers reduce MMP by 7.4–7.6 MPa, alcohols by 9.4 MPa, and surfactants by 1–6.1 MPa.
Within this dataset, field-scale CO2 utilization rates range from 167 to 227 standard cubic metres of CO2 per stock-tank barrel of oil recovered. Approximately 60% of injected CO2 can be retained at breakthrough if reinjection is not applied. The Weyburn-Midale project stored approximately 18 megatonnes of CO2 by 2011, while the Liuhua oilfield WAG scenarios showed CO2 storage efficiency exceeding 84% at optimal WAG ratios below 1:2.
Equinor Energy AS (originally filing as Statoil Petroleum AS) is the most prolific patent assignee in this dataset, with at least 9 active or pending patent documents spanning US, GB, AU, WO, NO, and CA jurisdictions. All filings originate from a single technical family focused on back-produced CO2 recycling systems for offshore CO2-EOR, with the GB priority application filed on February 7, 2017, and the most recent AU divisional filed in May 2025.
CO2 huff-and-puff (cyclic stimulation) involves injecting CO2 into a tight or shale reservoir, allowing it to soak and diffuse into the low-permeability matrix, then producing the oil-swollen fluid back. CO2 diffusion into the tight matrix is identified in this dataset as the dominant recovery mechanism when convective flow is limited. A seven-cycle CO2 pre-injection fracturing experiment on continental shale oil reservoirs in this dataset achieved an average oil recovery factor of 39.27%, a relative increase of 31.6% over conventional huff-and-puff.
Petrobras filed a US patent in March 2025 introducing saline rock caverns as control-volume buffers within WAG injection loops, enabling simultaneous EOR and CCUS using existing oil field infrastructure. This represents a novel architectural departure from conventional reservoir-only CO2 storage — a new category of engineered subsurface system where CO2 serves multiple simultaneous functions. It reflects Brazil’s unique offshore pre-salt context and the operator’s long-standing CCUS program (PROCLIMA/CENPES).
The most recent filings in this dataset are two CN active patents from Chengdu University of Technology filed in February and July 2025, covering integrated CO2 geological storage with shale oil recovery and geothermal energy development. An Equinor AU divisional was also filed in May 2025 extending protection on back-produced CO2 recycling for offshore EOR. Petrobras’ US patent covering saline cavern CCUS-EOR integration was filed in March 2025.
Data and insights on this page are based on a limited patent and literature dataset and are for reference only. Figures may not represent the complete technology landscape.