Objective
This article outlines the best practices for simulating CO₂ transport and injection applications using OLI software. Simulating these scenarios entails understanding field conditions as well as laboratory or simulated autoclave environments. The recommendations outlined in this document address thermodynamic framework selection and redox enablement to help you create simulations that accurately represent your system.
Disclaimer: These recommendations apply to OLI software versions 11.5 and 12.0.
CO₂ Transport Simulation
The table below showcases three common scenarios in CO₂ transport: field conditions, laboratory or autoclave loading, and simulations of the system’s PVT behavior to compare to non-OLI models.
For additional insights into modeling CO₂ transport in OLI, please see our blog.
| Field Conditions | Laboratory / Autoclave Conditions | Determine PVT Behavior | |
| Thermodynamic Framework |
MSE to enable redox reactions necessary for calculating acid dropout |
MSE-SRK to replicate the initial, unreacted conditions at time zero (t=0) |
MSE-SRK |
| Redox Enablement |
Yes Sulfur (-2, 0, +4, +6) Nitrogen (+2, +4, +5) |
No to preserve the system’s unreacted state (t=0) |
No |
| Additional Notes | A corrosion rate for carbon steel cannot be calculated because the dense phase is CO₂-rich rather than H₂O-rich. The MSE corrosion framework is required. As of V12, carbon steel is not available as a metallic material in the MSE corrosion framework; only two alloys, 2205 and 2507, are available. | Use autoclave calculations to determine the required impurity loading at ambient conditions to match target impurity levels in each phase at the target final temperature and pressure. | Objective: replicate the PVT diagram of CO₂ in the presence of impurities. |
CO₂ Injection Simulation
This section covers cases where a CO₂-rich phase interacts with a brine.
For OLI modeling examples of CO₂ injection, please see our blog.
| Field Conditions | Laboratory / Autoclave Conditions | |
| Thermodynamic Framework |
MSE to enable redox reactions necessary for calculating acid dropout |
MSE, as the simulation includes both Liquid-1 (water-rich) & Vapor phases |
| Redox Enablement |
Yes Sulfur (-2, 0, +4, +6) Nitrogen (+2, +4, +5) |
No to preserve the system’s unreacted state (t=0) |
| Additional Notes | Can predict corrosion rates of carbon steel and other alloys using the AQ framework, if the Liquid-1 phase >= 65 mol% H2O | Use autoclave calculations to determine the required impurity loading at ambient conditions to match target impurity levels in each phase at the target final temperature and pressure. |
General Guidance
- In cases where nitrogen redox is enabled, we do not recommend enabling the N(0) oxidation state. This state corresponds to N₂, which is extremely thermodynamically stable and would unrealistically drive equilibrium conversion toward N₂.
- For a complete list of CCTUS impurities available in MSE and MSE-SRK, please refer to this article.
Conclusion
This document summarizes high-level best practices for simulations involving CO₂ transport and injection. For guidance tailored to your specific system, please feel free to submit a ticket.