Estimation of Suspended Particle Retention Rate and Permeability Damage in Sandstone from Back Analysis of Laboratory Injection Tests
Notice bibliographique
Résumé
Abstract This paper investigates the suspended particle retention rate and permeability damage in porous sandstone during produced water injection process. The data used in this study was obtained from one-dimensional constant rate injection tests in which both the effluent concentration and the pressure drop were recorded. The particle retention process was modeled as a filtration process using finite difference method. The intrinsic filtration and permeability reduction functions were determined by matching the overall measured effluent concentration and pressure drop data. Least square method was used as an optimization technique in the back analysis. Introduction Produced water re-injection process is considered as the most suitable and economical method to dispose the produced waste water with minimum environment impact. However, the loss of permeability and injectivity due to the particle retention within the formation around the injection wells is a common problem in this process. Mettananda (2005) conducted 1-D injection tests with particle suspensions to study the particle retention and permeability reduction in sandstone specimens. In this paper, systematic methodologies are developed to analyze the results measured from these injection tests to determine the filtration and permeability reduction functions. Particle suspension Injection experiments (Mettananda 2005) Materials and fluids used The sandstone specimens used in the study were recovered at depths of about 1750–1774 m from Camaal-30 Well of the Qishn formation, Masila block, Yemen. Specimens of 3.8 cm in diameter and 6.3 cm in length were trimmed from drilled cores. Fig. 1 shows a typical thin section of Qishn sandstone specimen. Results from mercury intrusion porosimetry tests show that the porosity values lie in a range of 0.17-0.23, and the median pore throat sizes are within 10–33 µm. Fig. 2 shows a typical pore throat size distribution of Qishn sandstone specimen. Formation water present in oilfields is usually brine. Results of the chemical analysis of Qishn sandstone formation water showed that the main cations present are Na+ and Ca2+ while the main anions are Cl−, SO42-and HCO3-. Based on the milliequivalents, the equivalent NaCl concentration was estimated to be 2646 mg/l. To be on the conservative side, 5 g/l NaCl brine was used in the flow experiments. Silica fume was selected to be the type of particle used in the experiments. Silica fume is a commercially available admixture used in concrete material. It does not flocculate in NaCl solution and has a wide size range of 0.4 µm to 60 µm. Based on the pore throat size distribution of the core specimens (median pore throat sizes are 10–33 µm), the injected particles should have a size range between approximately 0.6 µm to 8 µm. Sedimentation method was used to achieve a good separation. Test setup In this study, a flexible wall permeameter (ASTM D 5084- 03) was used in the 1-D injection tests. In this method, the same confining pressure is applied to the specimen, both in radial and axial directions. A schematic of the permeameter used is shown in Fig. 3.
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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 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 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 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 ».