Speaker
Description
Foam-assisted water alternate gas injection (FAWAG injection) could be a promising technology to assist gas mobility control, consequently gas management in surface facilities of ultra-deepwater fields in the Brazilian offshore (Vieira et al., 2020). In these fields carbon dioxide (CO2) concentration in the gas stream varies, which can negatively impact foam stability, accelerating its destruction (Abdelaal et al., 2020). However, the impact of CO2 concentration in the gas stream is seldomly evaluated. In this work, we evaluate the impact of CO2 concentration in the gas phase on foam generation and foam strength (apparent viscosity) in porous media.
To this end, we conducted coreflood experiments where gas phase and surfactant solution were co-injected through Indiana limestone under relevant conditions (temperature – 65C, pressure – 10 MPa and superficial velocity – 3.5 x 10-6 m s-1). Four different gas compositions were used for the tests, namely nitrogen (N2), CO2 and two CO2-N2 mixtures (10 mol%, 50 mol%). Two commercial zwitterionic surfactants (CAHS – cocamidopropyl hydroxysultaine and CB – cetyl betaine) were used at 0.5 wt.% concentration (active matter) as foaming agents. The experiments were carried out with the core mounted in vertical position and the injection direction was bottom-to-top.
Our results have shown that increase in CO2 concentration in the gas phase decreased overall apparent viscosity (foam), but no linear correlation has been found. Maximum foam values for CB ranging from 30 mPa s-1 for CO2-foam to 170 mPa s-1 for N2-foam. For CAHS, maximum foam values ranged between 70 mPa s-1 and 170 mPa s 1 for the same conditions. Gas composition also impacted transition foam quality (fg), however, the changes in foam behavior as a function of gas fraction seemed to be dependent of the structure of zwitterionic surfactant. For CB surfactant, increased CO¬2 concentration in gas phase (10 mol% and 50 mol% CO2-N2) shifted foam transition quality to the lower gas fractions (from 0.6 to 0.4), indicating that coalescence was favored under these conditions. The apparent viscosity of the foam formed between CO2 and CB surfactant solution did not present a clear transition, and it remained constant as a function of foam quality. Under the same conditions, fg for CAHS was shifted to the right (0.5 to 0.7), indicating that resistance to coalescence increased as a function of CO2 concentration on the gas phase for this surfactant. Another important observation was that from a gas fraction of 0.9, foam apparent viscosity was independent of gas composition. That meant that N2-, gas mixture- or CO2-foam had the same foam apparent viscosity (CAHS ~ 20 mPa s-1, CB ~ 10 mPa s-1), indicating that this regime was dominated by limiting capillary pressure.
These findings suggest that for FAWAG project gas stream has considerable variation in CO2 concentration, the surfactant chosen not only needs to tolerate salinity and temperature of the reservoir, but also needs to maintain a high fg* under these changing gas composition conditions.
References
Abdelaal, A., Gajbhiye, R., Al-Shehri, D., 2020. Mixed CO 2 /N 2 Foam for EOR as a Novel Solution for Supercritical CO 2 Foam Challenges in Sandstone Reservoirs. ACS Omega 5, 33140–33150. https://doi.org/10.1021/acsomega.0c04801
Façanha, J.M.F., Lopes, L.F., Fritis, G., Godoy, P., Weber dos Santos, R., Chapiro, G., Perez-Gramatges, A., 2022. Bubble-growth regime for confined foams: Comparison between N2–CO2/foam and CO2/foam stabilized by silica nanoparticles. J. Pet. Sci. Eng. 218, 111006. https://doi.org/https://doi.org/10.1016/j.petrol.2022.111006
Lopes, L.F., Façanha, J.M.F., Maqueira, L., Ribeiro, F.R.T., Pérez-Gramatges, A., 2021. Coarsening reduction strategies to stabilize CO2-foam formed with a zwitterionic surfactant in porous media. J. Pet. Sci. Eng. 207, 109141. https://doi.org/10.1016/j.petrol.2021.109141
Vieira, R.A.M., Pizarro, J.O.S., Oliveira, L.A., Oliveira, D.F.B., Passarelli, F.M., Pedroni, L.G., 2020. Offshore EOR Initiatives and Applications in Brazil: An Operator Perspective. Proc. Annu. Offshore Technol. Conf. 2020-May. https://doi.org/10.4043/30780-ms
| Participation | In-Person |
|---|---|
| Country | Brazil |
| MDPI Energies Student Poster Award | No, do not submit my presenation for the student posters award. |
| Acceptance of the Terms & Conditions | Click here to agree |
