External Corrosion Behavior of Oil Pipelines with Polyethylene Coating under Pressure Fluctuations
Notice bibliographique
Résumé
Abstract External corrosion on buried pipe steels has been demonstrated to be a major threat to pipeline integrity. Although it has been extensively investigated and well understood electrochemically, there is no particular corrosion rate model that is widely accepted by industry due to the complexities associated with coating performance, and heterogeneity of the soil environment (including bacteria, drainage, bulk resistivity, CP level, etc.). This paper demonstrates that the severity of external corrosion on Polyethylene (PE) tape coated oil pipe is exacerbated by the proximity to upstream (U/S) pump stations, and suggests mechanistic explanations related to pressure fluctuations. External corrosion features reported by the most recent In-Line Inspection (ILI) Ultrasonic Wall Measurement (UTWM) tools for three oil pipelines were correlated with the distance to U/S pump stations. UTWM ILI data is used as it includes features that are located under repair sleeves. These three oil pipelines with PE coating were investigated for a total length of approximately 3100 km. The pipelines have been in service for more than 40 years. One of the pipelines has experienced reversed flow operation. Analysis of the results shows that external corrosion features with depths < 20% Wall Thickness (WT) reported by UTWM tools are distributed uniformly along the pipelines. However, a clear increase in the frequency of corrosion features with depths >= 20%WT is seen within 10 km from the U/S pump station. There is a pronounced increase in the density of deeper feature classes in the same region. This phenomenon was also observed on the third oil pipeline with reversed flow directions. In addition, this trend is further validated by the distribution of field excavations triggered by external corrosion. Based on these data, it is evident that the frequency and severity of external corrosion on these tape coated pipelines is positively correlated to U/S pump station proximity. Possible mechanisms may include mechano-electrochemistry, and pressure fluctuations that facilitate electrochemical processes and/or PE tape coating damage: 1) Pressure fluctuations increase dislocation density and thus electrochemical potential ahead of the corrosion tip due to stress concentration. 2) Pressure fluctuations may refresh the electrochemical environments against the pipe surface and thus exacerbate corrosion. 3) The PE coating damage is accelerated (mechanically) by pressure fluctuations. The findings in this paper could help External Corrosion Direct Assessment (ECDA) locate severe corrosion features, especially for lines that are non-piggable. Also, these discoveries can provide guidance for future research and pipeline integrity management with external corrosion.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».