Assessing the impact of pressure on in-situ rheology and the effectiveness of polymer-enhanced foams for CO2 storage
Author Identifier (ORCID)
Stefan Iglauer: https://orcid.org/0000-0002-8080-1590
Abstract
Polymer-enhanced foams have demonstrated high stability and improved rheology in porous media, rendering them promising for CO2 storage in carbonate reservoirs. However, limited experimental data exist on the in-situ rheology of polymer-enhanced supercritical CO2 foams under varying pressure conditions. This study aims to investigate the effects of polymer on foam stability and its in-situ rheology in carbonate core plugs across various pressure and gas fraction settings under high-temperature and high-salinity conditions. Polymers and surfactants were selected from multiple candidates after extensive screening under high temperatures and saline conditions. Foam bulk tests using CO2 were conducted at 95°C, with the aim of determining foam half-life and selecting the optimal foam formulations. Coreflooding tests were performed at 95°C using Indiana limestone core plugs. The tests included initial brine and supercritical CO2, and then foam injection at various foam quality settings. The in-situ rheology of both polymer-enhanced and polymer-free foams was evaluated at the best foam quality. The back pressure was varied from 1300 to 2000 psi to assess the detailed in-situ rheology of the foam, sweep efficiency, and CO2 storage potential. The thermal stability and salinity tolerance test results indicated that ATBS-based polymers and anionic and zwitterionic surfactants showed the desired stability. Bulk foam experiments revealed that the polymer-enhanced foam (PEF) formulation had better foamability and stability, indicating that polymers increase lamellae resistance to rupture and reduce gravity drainage effects. Coreflooding tests showed that the PEF formulation excelled at 80% foam quality (drier foam), while the polymer-free foam (PFF) peaked at 70%. This indicates that adding polymers enhances foam stability through improved film reinforcement, reduced gas diffusion, and minimized coalescence. Regarding foam performance, the gas mobility reduction factor (MRF) was higher for PEF (126) than for PFF (54) at 1 cc/min. Furthermore, PEF exhibited superior shear-thinning behavior compared to the PFF, showcasing its best performance under high-shear conditions. The results of varying back pressure demonstrated that PEF exhibited a significantly improved MRF at high pore pressure settings compared to PFF. This improvement is due to the greater structural strength provided by polymer molecules. PEF also confirmed that foam performance is better under conditions of higher permeability when different core plugs are compared. Overall, polymer-augmented foam showed an excellent CO2 storage capacity of 49%, compared to 7.05% for CO2 injection without foam after 1 PV of injection. Conventional foams using supercritical CO2 can be unstable, often leading to coalescence and rapid collapse. This unique study provides detailed insights into the flow behavior of polymer-enhanced foams and traditional polymer-free foams. By varying gas fraction, flow rates, and back pressure, we evaluated these foams for CO2 mobility reduction for long-term sequestration in Middle Eastern carbonate reservoirs. This research aims to help achieve ambitious net-zero targets through effective CO2 geo-storage solutions.
Keywords
Polymer‑enhanced foams, CO₂ storage, in‑situ rheology, carbonate reservoirs, foam stability, coreflooding experiments
Document Type
Conference Proceeding
Date of Publication
1-1-2026
Publication Title
Society of Petroleum Engineers Kuwait Oil and Gas Show
Publisher
Society of Petroleum Engineers
School
Centre for Sustainable Energy and Resources
Funders
Khalifa University of Science and Technology (RIG-2023-036) / RICH Center (RC2-2019-007)
Copyright
subscription content
Comments
Mushtaq, M., Mumtaz, M., Al-Shalabi, E. W., Alameri, W., Karanikolos, G., & Iglauer, S. (2026, February). Assessing the impact of pressure on in-situ rheology and the effectiveness of polymer-enhanced foams for CO₂ storage [Conference presentation]. Kuwait Oil & Gas Show, Kuwait City, Kuwait. https://doi.org/10.2118/231029-MS