Small-Diameter Gas Lift Systems-A Viable Technical Solution for Transport of Fluids From Low-Pressure Reservoirs
Notice bibliographique
Résumé
Abstract Production of fluids from low-pressure reservoirs requires a continuous or an intermittent artificial lifting technology. If the shut-in fluid level is less than 20% of the depth of the well finding a suitable and economic artificial lifting technology is a challenging task. Depending on local conditions and economics, gas or steam lifting alone or associated with other artificial lifting technologies is selected. Within a limited range of gas-liquid flowrates, use of smalldiameter gas lifting technology is better suited than the gas lifting using conventional tubing to produce liquids from lowpressure reservoirs. Laboratory investigations dedicated to small-diameter gas lifting operations have been so far limited to fluid transfer operations requiring maximum 10–20 m. This study responds to the industry need for a better evaluation of depth - diameter flowrates limitations in view of assessing the potential field application of gas lifting for very low reservoir pressures and relatively small liquid flowrates. Production of oil and gas from pressure-depleted reservoirs, recovery of methane from coalbed reserves, and efficient drainage of heavy oil and saturated high-temperature condensate produced under steam-assisted gravity methods, where reservoir pressure is marginally low, require a revisiting of conventional artificial lifting technologies. For example, there are thousands of dormant gas wells where bottom water aquifers of 50 m or less impede gas production. Similar conditions are often found in the coalbed methane reservoirs. Use of submersible electric pumps for lowpressure, low liquid production reservoirs is rarely an economic or a viable technical option. The availability of gas and the relatively small amount of liquid to be transferred suggest gas lifting as a potential strategy for producing the reservoir water and releasing the gas. However, conventional gas lifting (using tubes with a diameter D>1 in.) is not possible due to the extreme low reservoir pressure conditions. Small diameter pipes (D<1 in.) were occasionally used for gas lifting operations in such fields with mixed results. In this paper, a critical review of the existing literature on the numerical evaluation methods of gas lifting was presented first. Laboratory tests were conducted by using a specially designed rig and the results were used to evaluate the accuracy of the existing model predictions. Experimental results were also used for assessing the effect of gas-liquid flowrate and interfacial tension on the liquid production rate and flowing bottomhole pressure. Experimental data were further used for developing a model to determine critical limit of the small diameter gas lifting technique under field conditions. The new model, better adapted for the needs of the industry, can be used to transfer laboratory information to the field scale. Introduction Gaslifting or airlift has been used to remove water from flooded mines since 17821–2. Today, natural gaslifting is commonly used for oil wells where gas and liquid are produced together. Conventional gaslifting uses tubing (or ducts) with a diameter greater than 1 in. Vertical upward transport of gas and liquid for such conditions is well investigated and both empirical3 and mechanistic models are available.4–6
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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 | 0,001 | 0,001 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 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 ».