A groundbreaking advancement in enhanced oil recovery technology has emerged from the laboratories of The University of Texas at Austin, introducing a novel method that not only boosts oil extraction efficiency but also significantly enhances carbon sequestration. This innovative approach, centered on the use of aqueous formate solutions alongside carbon dioxide (CO₂), promises to challenge the established paradigms of carbon-based enhanced oil recovery (EOR) by increasing oil yield and securing more carbon underground in a safer and more effective manner.
Conventional CO₂-based EOR involves injecting CO₂ gas into oil reservoirs to displace and mobilize residual oil trapped within rock pores. While this method aids in extracting additional oil and concurrently stores some carbon dioxide, it is limited by the physical and chemical properties of CO₂ gas under reservoir conditions. The new method replaces sole reliance on gaseous CO₂ with a synergistic injection strategy, alternating slugs of CO₂ gas with aqueous solutions of formate compounds, such as sodium formate or potassium formate. These formate ions, synthesized directly from CO₂, act as advanced carbon carriers that alter fluid dynamics and storage capabilities within the geological formations.
From a geochemical perspective, formate molecules present several favorable attributes when compared to CO₂ gas. Their aqueous nature provides higher viscosity, which improves the sweep efficiency of injected fluids through complex pore networks, allowing a more uniform displacement of oil toward production wells. Additionally, formate compounds demonstrate enhanced adsorption and retention within rock formations, leading to more secure and extensive carbon storage. This chemical stability in the subsurface environment preserves reservoir integrity and reduces the risk of carbon leakage, a concern that has traditionally challenged large-scale carbon sequestration efforts.
The research team at UT applied this Formate-Alternating-Gas (FAG) injection method in high-fidelity reservoir simulations modeled on data from the prolific Permian Basin in West Texas. The simulations revealed that this innovative technique could increase oil recovery by up to 19.5% relative to traditional CO₂ gas injection methods alone, and by nearly 2% compared to combined CO₂ and water injection scenarios. More strikingly, the approach enhanced carbon sequestration capabilities by as much as 17.9% in comparison to the CO₂-water hybrid injections, marking a major leap forward in coupling hydrocarbon extraction with climate mitigation efforts.
A critical dimension of these findings lies in the security of carbon storage. The alternating injection of formate-rich aqueous solutions and CO₂ gas minimizes the volume of free-flowing CO₂ in the reservoir. Free-phase CO₂ is more prone to migration and potential escape from the storage site, which undermines long-term sequestration goals. By chemically buffering the reservoir environment, the formate solutions promote stable carbon retention both in dissolved and mineral-bound forms. This multifaceted locking mechanism underscores the method’s potential to safeguard subsurface environments while maximizing carbon immobilization.
Technologically, synthesizing formate compounds economically and at scale remains a challenge that must be addressed before the FAG method can be fully commercialized. Current industrial processes for converting captured CO₂ into sodium or potassium formate require refinement and scaling to meet the demands of field application. Despite these hurdles, financial incentives related to carbon storage credits and regulatory support could accelerate the transition of this technology from laboratory modeling to operational reality, especially as policymakers increasingly target net-zero carbon goals.
Co-author Ryosuke Okuno emphasized that rethinking the role of CO₂ in EOR presents an opportunity to transcend conventional limits. “Instead of using CO₂ directly, converting it into a more effective carbon carrier, like formate species, allows for better oil displacement and more secure carbon storage,” Okuno explained. This reflects a nuanced understanding of reservoir chemistry and fluid mechanics, leveraging molecular innovations to redefine subterranean carbon management.
Lead author Abouzar Mirzaei-Paiaman highlighted the importance of synchronizing technological innovation with policy frameworks. His research suggests that structured financial incentives focused on maximizing carbon storage could generate significant market demand for carbon carrier compounds, thereby stimulating investment and scaling of the formate synthesis industry. This alignment between science, industry, and legislation is essential for deploying the FAG method at industrial scales.
On the environmental front, the FAG injection strategy embodies a promising synergy between fossil fuel extraction and climate action. By significantly increasing the amount of CO₂ sequestered during the production of oil, it helps reduce the net carbon footprint of hydrocarbon fuels. Such advances are critical during the ongoing global transition toward sustainable energy systems, enabling responsible resource utilization while carbon management technologies mature.
From a reservoir engineering standpoint, introducing viscous, aqueous formate solutions into the heterogeneous rock matrix enhances displacement efficiency by mitigating fingering and channeling effects that commonly limit sweep efficiency in conventional gas injection EOR methods. Furthermore, the chemical buffering properties of formate reduce the risk of reservoir rock degradation, supporting long-term structural integrity and performance.
The University of Texas research was supported by the State of Texas Advanced Resource Recovery (STARR) program and the Energi Simulation Industrial Affiliate Program on Carbon Utilization and Storage. These collaborations underscore the strategic importance of optimizing resource recovery while advancing environmental stewardship, education, and economic development.
Published in the American Chemical Society’s Energy & Fuels journal, the study titled “Formate-Alternating-Gas (FAG) Injection Method Using Aqueous Formate Solution and CO₂ for Optimizing Oil Recovery, Carbon Sequestration, and Storage” marks a significant milestone in applied geosciences and petroleum engineering literature. Its insights are poised to influence how energy companies, policymakers, and climate strategists approach enhanced oil recovery in an era demanding integrated energy and carbon management solutions.
While still emerging, the formate-based carbon carrier technology holds transformative potential for the oil and gas industry, providing a compelling pathway toward maximizing resource recovery and carbon mitigation concurrently. As research continues to scale this approach and overcome practical challenges, this innovative method could redefine the environmental and economic dynamics of fossil fuel exploitation in the coming decades.
Subject of Research: Enhanced Oil Recovery and Carbon Sequestration Using Formate-Based Carbon Carriers
Article Title: Formate-Alternating-Gas (FAG) Injection Method Using Aqueous Formate Solution and CO₂ for Optimizing Oil Recovery, Carbon Sequestration, and Storage
News Publication Date: 3-Jul-2025
Web References: Energy & Fuels Article
References: Mirzaei-Paiaman et al., Energy & Fuels, 2025
Image Credits: Mirzaei-Paiaman et al.
Keywords: Enhanced Oil Recovery, Carbon Sequestration, Formate Solution, Carbon Carriers, CO₂ Injection, Oil Reservoirs, Carbon Capture, Geochemistry, Reservoir Engineering, Climate Change, Nonrenewable Resources, Energy & Fuels
