Effect of Oxidation on Base Liquids of Oil and Synthetic-Based Drilling Fluids at High Pressures and High Temperatures
Notice bibliographique
Résumé
Abstract Diesels and distillates are used as the base liquid for the majority of oil-based drilling fluids in conventional drilling and as the liquid phase in gasified liquids in some underbalanced drilling operations. They are also used as the friction reducing agents in situations such as freeing stuck pipe. Understanding the true downhole rheological properties is crucial as they affect equivalent circulating density, hole cleaning, barite sag, surge/swab pressures during tripping, pump pressure and bit hydraulics. Moreover, gelation and excessively high viscosity are major concerns, especially at high temperatures. This paper presents the results of an experimental investigation which was aimed at establishing the effect of oxidation on some base liquids for oil-based and synthetic based drilling fluids at high pressures and high temperatures. Base liquids were aged at 150 °C and 14 MPa initial pressure in the presence of air for 60 hours. Characterization of gas and liquid phases and measurements of solid phase has beencarried out. Viscosity measurements at temperatures and pressures ranging from 20 to 152 °C and atmospheric to 103.4MPa, respectively, have been performed. The viscosity of the liquid samples after aging is compared with that of corresponding fresh samples. The results show that the degree of oxidation plays an important role in increasing the sample viscosity. This increase in viscosity is a function of temperature, and is more significant at low temperatures. Furthermore, agitation of samples during aging with air resulted in increased amounts of solid precipitation while lowering the viscosity of the liquid phase. Introduction Historically, in-situ combustion (1),(2) and high pressure air injection (HPAI) (3) are two major areas in thermal enhanced oil recovery techniques that oxidation of oils are of special importance. In these processes it is of vital importance to know what effects the oxidation has on rheological properties of the oil, because it affects the mobility of the oil and therefore the recovery factor. Another area that in which oxidation of oils can be an issue is drilling a well. (4) Generally a well can be drilled either by conventional drilling or underbalanced drilling (UBD) techniques. (5) In conventional drilling employing oil-based drilling fluids in hot wells, the hot oil is returned to the surfacetanks and is exposed to air. Since the base liquids in oil-based drilling fluids are expensive, they are used in many wells before disposal. Therefore, even if the rate of oxidation is low, the long time of exposure can result in substantial oxidation of the oil.On the other hand, in underbalanced drilling a variety of different drilling fluids such as dry air, nitrogen, natural gas, mist, stable foam, stiff foam, gasified liquids (aerated muds), glass bubbles and liquids are used. (5) In some gasified liquids (aerated muds), the liquid phase is primarily light oils (diesels, distillates,...). Deoxygenated air from membrane units (air with about 5 percent oxygen content) is used as the gas phase. (6) In this case, oxidation is more severe, because deoxygenated air is continuously exposed to oil downhole at higher temperature and pressure conditions.
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 | 0,000 |
| 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 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 ».