Notice bibliographique
Résumé
Abstract The Terra Nova wellheads are sited in depressions ("Glory Holes") made in the seabed to protect the wellhead equipment from iceberg impact. This paper describes the construction of the Terra Nova Glory Holes including the choice of protection system, the choice of excavation method, onshore preparation and offshore operations. It concludes with a discussion on the use of the chosen excavation technology for other applications in the offshore oil and gas industry. Introduction The Terra Nova Oil Field Development is located offshore Newfoundland, Canada, some 350 km ESE of the provincial capital, St. John's. The field is located in an area, which is subject to iceberg migration. Bottom scouring icebergs are known to have traversed the region in the past, as evidenced by scour marks of up to 1.5 metres deep on the seafloor. The water depth at the Terra Nova field is 95 metres and a bottom-scouring iceberg has a mass in the order of several million tonnes. If such an iceberg were to collide with subsea wellhead equipment, the consequences are potentially severe. Terra Nova has a comprehensive ice management strategy based on detection, monitoring and deflection, to prevent iceberg encroachment into the vicinity of the field. However, the application of such an ice management strategy does not guarantee that the encroachment of icebergs into the area will be completely avoided. It is thus, necessary, to protect the subsea wellhead equipment from bottom scouring icebergs. Detailed studies conducted by Terra Nova Alliance member Coflexip Stena Offshore concluded that the optimum way of protecting the subsea wells from bottom scouring icebergs is to site the wellhead equipment in excavated depressions (termed "Glory Holes") in the seabed (Fig.1). The Terra Nova Glory Holes were constructed in the summer of 1999 using trailer suction dredging technology. A Glory Hole was constructed at each drill centre; five in all, each being 10 metres in depth. The largest Glory Hole has a base area of 65 metres by 25 metres, and is roughly equivalent in size to a tennis stadium. Wellhead Protection Method Selection Whilst Terra Nova is using open Glory Holes as a means to provide protection to the subsea equipment, a number of wellhead protection methods were considered Cased Glory Hole: This method involves placing the wellhead and Christmas tree in a steel or concrete silo typically 8 metres in diameter. Installation would normally be carried out from a drilling rig. The silo is installed prior to the commencement of drilling operations. The silo has a weak-point at a pre-determined elevation below sea level. In the case of iceberg impact, the silo is sheared at the weak point and the upper part of the silo is sacrificed, leaving the lower part of the silo, the wellhead and the Christmas tree in tact. The Cased Glory Hole is particularly suited to single wellheads. Caisson Completion Method: This method involves a seabed level Xmas tree with the wellhead situated below the iceberg scour line. Installation is carried out from the drilling rig.
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 distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| 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 | 0,002 |
| 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) | 0,000 | 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 tête enseignante, 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 ».