Notice bibliographique
Résumé
This article, written by Technology Editor Dennis Denney, contains highlights of paper SPE 90422, "Enhanced Hydrate Inhibition in Alberta Gas Field," by Dana Budd, EnCana Corp., and Danica Hurd, SPE, Marek Pakulski, SPE, and Thane D. Schaffer, SPE, BJ Chemical Services, prepared for the 2004 SPE Annual Technical Conference and Exhibition, Houston, 26-29 September. Operating gas wells in southern Alberta poses challenges. High bottomhole pressure in new wells, low bottomhole temperatures, and the Joule-Thompson expansion-cooling effect (which often lowers the gas-stream temperature below the brine freezing point) create conditions favorable for the formation of gas hydrates in wells and transportation pipelines. The problems are aggravated during cold winter months, when wells and pipelines have strong tendencies to plug with hydrates and ice. Systematic laboratory work was undertaken to explore synergistic effects between methanol and low-dosage hydrate inhibitors (LDHIs). A strong effect was discovered at a certain ratio of methanol and low-molecular-weight oligomer-type hydrate inhibitor. Introduction Gas hydrates form when water molecules crystallize around “guest” molecules. The water/guest crystallization process occurs at many combinations of temperature and pressure. Light hydrocarbons (methane to heptanes), nitrogen, carbon dioxide, and hydrogen sulfide are the guest molecules of interest to the natural-gas industry. Depending on pressure and gas composition, gas hydrates may build up at any place where water coexists with natural gas at temperatures as high as 30°C. Gas-transmission lines and new gas wells are particularly vulnerable to being blocked with hydrates. Formation of gas hydrates can be eliminated or slowed by several methods. Thermodynamic prevention methods control or eliminate elements necessary for hydrate formation: the presence of hydrate-forming guest molecules, the presence of water, high pressure, or low temperature. Eliminating any one of these four factors from a system precludes the formation of hydrates. Unfortunately, elimination of these hydrate elements is often impractical or even impossible. For long subsea transmission lines, heating and insulating is a common mechanical solution to hydrate problems. Hydrates will not form if the gas/water system is kept at a temperature greater than the hydrate-formation temperature. Gas dehydration is another method of removing a hydrate component. However, in a practical field operation, water can be economically removed only to a certain vapor pressure, and residual water vapor always exists in a dry gas. Hydrate plugs in “dry” gas lines have been reported. Adding chemicals to the gas/water streams is the most common method of preventing hydrate formation. Large amounts of alcohols, glycols, or salts are used. These additives thermodynamically destabilize hydrates and effectively lower the hydrate-formation temperature. They function by bonding to water molecules through hydrogen bonds or solvation.
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 | 0,000 |
| 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 | 0,001 |
| 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 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 ».