Optimization of CO-WAG and Calcite Scale Management in Pre-Salt Carbonate Reservoirs
- Hydra Rodrigues (Heriot-Watt University) | Eric Mackay (Heriot-Watt University) | Daniel Arnold (Heriot-Watt University) | Duarte Silva (Heriot-Watt University)
- Document ID
- Offshore Technology Conference
- Offshore Technology Conference Brasil, 29-31 October, Rio de Janeiro, Brazil
- Publication Date
- Document Type
- Conference Paper
- 2019. Offshore Technology Conference
- Scaling Management, Operational Design, Enhanced Oil Recovery, Reactive Transport, Carbon Capture Utilization and Storage
- 70 in the last 30 days
- 72 since 2007
- Show more detail
- View rights & permissions
CO2-WAG (Water-Alternating-Gas) has been applied in offshore Brazilian oilfields to improve recovery rates and mitigate the environmental impact that venting produced CO2 would bring. Although CO2 is highly miscible in oil under these reservoirs conditions, this gas is also extremely mobile, and its speciation in the aqueous phase drives reactions with carbonates that can cause severe inorganic scaling problems in production systems. It is crucial, therefore, to effectively design CO2-WAG operations for mobility control and, consequently, enhance reservoir performance, CO2 utilization and flow assurance.
This paper addresses the design optimization of coupled CO2-EOR and storage operations applied to the Brazilian Pre-salt offshore context (reservoir properties, infrastructure, regulatory framework and economic characteristics), examining the trade-offs of project profitability, CO2 utilization and calcite scale risk. Several compositional simulations of miscible WAG scenarios were performed and key design parameters were optimized using statistical sampling and evolutionary algorithms. Aqueous and mineral reactions were included in the calculations, allowing us to quantify the calcite mass that can potentially deposit in the perforations and production system.
The results showed how optimizing WAG operations can significantly improve the economics and the scale management of oil production from carbonate reservoirs. The optimal WAG design greatly increased incremental NPV per volume of CO2 stored and reduced calcite scale risk by simply rearranging the WAG slugs in a tapered manner.
Here we demonstrate that this methodology can be used to determine how to recycle CO2 in a given field for better economics and lower carbon footprint, doing so without triggering calcite mineral deposition to the point of permanent jeopardy of production wells and facilities operability. Therefore, the workflow integrates critical challenges that are correlated, yet often addressed independently, supporting the complex decision-making of CO2-EOR operational design in carbonate reservoirs.
|File Size||1 MB||Number of Pages||13|
Alusta, G.A., Mackay, E.J., Fennema, J. and Collins, I., 2011, January. EOR vs. Infill Well Drilling: How to Make the Choice? In SPE Enhanced Oil Recovery Conference. Society of Petroleum Engineers. SPE-143300-MS. DOI: https://doi.org/10.2118/143300-MS.
Chen, S.M., Allard, D.R. and Anli, J., 1984, January. Factors affecting solvent slug size requirements in hydrocarbon miscible flooding. In SPE Enhanced Oil Recovery Symposium. Society of Petroleum Engineers. SPE-12636-MS. DOI: https://doi.org/10.2118/12636-MS.
Correia, M., Hohendorff, J., Gaspar, A.D.S. and Schiozer, D., 2015, November. UNISIM-II-D: Benchmark case proposal based on a carbonate reservoir. In SPE Latin American and Caribbean Petroleum Engineering Conference. Society of Petroleum Engineers. SPE-177140-MS. DOI: https://doi.org/10.2118/177140-MS.
de Andrade, A.M.T., Vaz, C.E.M., Ribeiro, J., Lopreato, L.G.R. and do Nascimento, R.F.S., 2015, May. Offshore Production Units for Pre-Salt Projects. In Offshore Technology Conference. OTC-25691-MS. DOI: https://doi.org/10.4043/25691-MS.
Galp. 2018. Capital Markets Day Presentation. London, 20 February 2018. https://www.galp.com/Portals/0/Recursos/Investidores/SharedResources/Apresentacoes/EN/CMD2018.pdf (accessed 23 August 2018).
Hadlow, R.E. 1992. Update of Industry Experience with CO2 Injection. Presented at the SPE Annual Technical Conference and Exhibition, Washington, D.C., 4-7 October 1992. SPE-24928-MS. DOI: http://dx.doi.org/10.2118/24928-MS.
Khan, M.Y., Kohata, A., Patel, H., Syed, F.I. and Al Sowaidi, A.K., 2016, November. Water alternating gas WAG optimization using tapered WAG technique for a giant offshore Middle East Oil Field. In Abu Dhabi International Petroleum Exhibition & Conference. Society of Petroleum Engineers. SPE-183181-MS. DOI: https://doi.org/10.2118/183181-MS.
MME (Ministério de Minas e Energia). 2019. Ministry of Mines and Energy, Brazil. Monthly Gas Industry Follow-up Report – January 2019. http://www.mme.gov.br/documents/1138769/0/Boletim_Gas_Natural_nr_143_JAN_19.pdf (accessed 12 March 2019).
Moortgat, J., Firoozabadi, A., Li, Z., & Espósito, R. (2010, January 1). A Detailed Experimental and Numerical Study of Gravitational Effects on CO2 Enhanced Recovery. Society of Petroleum Engineers. SPE-135563-MS. DOI: https://doi.org/10.2118/135563-MS.
Muggeridge A, Cockin A, Webb K, Frampton H, Collins I, Moulds T, Salino P. 2014 Recovery rates, enhanced oil recovery and technological limits. Phil. Trans. R. Soc. A 372: 20120320. DOI: http://dx.doi.org/10.1098/rsta.2012.0320.
Pariani, G.J., McColloch, K.A., Warden, S.L. and Edens, D.R., 1992. An approach to optimize economics in a West Texas CO2 flood. Journal of Petroleum Technology, 44(09), pp.984–1. SPE-22022-PA. DOI: https://doi.org/10.2118/22022-PA.
Rodrigues, H., Mackay, E. and Arnold, D., 2019. Impact of WAG Design on Calcite Scaling Risk in Coupled CO2-EOR and Storage Projects in Carbonate Reservoirs. SPE Reservoir Simulation Conference. SPE-193882-MS. Society of Petroleum Engineers. DOI: https://doi.org/10.2118/193882-MS.