Paraffin Cleanout in a Single Subsea Flowline Environment: Glycol to Blame?
Notice bibliographique
Résumé
Abstract Paraffin deposition was found in the RedHawk #2 subsea flowline and was successfully removed using a xylene slug swept by produced gas from the well. Testing indicated that the problem resulted from the interaction between glycol and produced condensate. Overtreatment with glycol and low produced water volumes contributed to the precipitation of paraffin and eventual plugging of the flowline. The objective of this procedure was to clear the restriction by pumping a slug of xylene into the flowline and producing the well to carry the solids to surface. Glycol can react negatively with the condensate in some dry gas wells, resulting in paraffin precipitation. When there is sufficient water present to mix with the glycol the problem does not occur, however a lack of water causes the glycol to react with the condensate and form paraffin. Clearing the restriction would eliminate a pressure drop in the flowline, thus allowing the well to produce at optimal rate and prolonging the well's life. All work was performed from the host spar facility using temporary separation equipment and platform methanol pumps. The RedHawk flowline restriction was successfully removed using two 25 bbl xylene slugs which were swept from the flowline with produced gas from the well. With the restriction removed, 982 psi of frictional loss was regained and the well was returned to optimal production. The deposition appears to be reoccurring, although at a much slower rate than before. However, any further reduction in glycol usage would not guarantee effective hydrate inhibition. Changing hydrate inhibitors is impractical due to platform equipment and annual cleanouts are a more cost effective option. It is quickly becoming critical to develop means of cleaning single flowline systems with highly efficient and low cost methods. By understanding new problems that arise and putting new solutions into practice operators can extend the life of some wells and avoid significant downtime and workover costs. Introduction RedHawk is an Anadarko Petroleum Corporation operated cell spar located in 5300' of water in Garden Banks Block 876, about 177 miles southeast of Cameron, LA in the Gulf of Mexico. Devon Energy Corporation is a 50% working interest partner in the RedHawk field. The platform consists of two dry gas subsea tie-back wells, shown in figure 1, that are treated with recycled MEG via RedHawk's Glycol Reclamation Unit (GRU) for hydrate inhibition. As the GB 877 #2 well's chokes were opened to maintain the target rate of 75 MMCFD, it became apparent that the chokes were no longer controlling the flow from the well but rather some other restriction in the flowline (see figure 2). Modeling and testing showed that there was a restriction in the flowline causing a pressure loss and limiting the production rate of the well. The restriction was initially thought to be the result of fluids from the initial completion cleanup or from a preexisting blockage that occurred during installation of the flowline.
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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 | 0,001 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,003 | 0,001 |
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 ».