Complexity Modeling
Tubular Corrosion Model
- Client
- Eni
- Country
- Italy
- Year
- 2021
- Industry
- Oil & Gas
- Service
- Reliability and Safety
For Eni, kwantis developed a tubular corrosion model for Carbon Capture and Storage (CCS) operations. It turns the material degradation caused by corrosion into a failure probability that feeds a Fault Tree Analysis (FTA).
The challenge
In CCS operations, corrosion from produced or injected fluids is the main parameter affecting tubular reliability. To include it in a risk assessment, the material degradation it causes has to be evaluated, interpreted and expressed as a failure probability.
Our approach
The model first identifies each material/fluid combination, so that corrosion is estimated only where the tubing is susceptible to it. Fluids that are compatible with the tubular material are excluded, to keep the estimate precise.
Corrosion is quantified as a corrosion rate in mm/y by tracking the thickness reduction, to safeguard tubular integrity and barrier efficacy. The process includes:
- Corrosion rate: calculated for sweet and sour corrosion. An industry-standard corrosion model covers mainly uniform sweet corrosion, and sour environment corrosion rates come from a data-driven rule of thumb.
- Failure rate: the corrosion rate and the thickness reduction allowance are converted into a failure rate in failures/hour.
- Probability of Failure on Demand: computed from the Mean Time to Repair, the monitoring frequency and the tubular material failure rate.
The outcome
Corrosion now enters the risk assessment of CCS operations as a failure probability within the FTA, and only where tubing materials are susceptible to the fluids they handle.
