Investigation of Proppant Shear Behavior Along Fracture/Fault Lines; A Gouge Analogy for Fracture Stability and Earthquake Potential
Notice bibliographique
Résumé
ABSTRACT: During Hydraulic fracturing of unconventional reservoirs, proppants keep fractures open after fracturing and thus increase reservoir deliverability. Typically fracture conductivity is used to quantify the efficiency of hydraulic fractures. The efficiency is highly dependent on the proppant placement during fracturing and proppant rearrangement/crushing when the fracture begins to close. This work introduces another criterion for evaluating the efficiency of the hydraulic fracturing operation. This is based on the stability of the fracture and its potential to induce seismic activity. Using the three major types of proppants (resin, ceramic, sand) used in hydraulic fracturing. We investigate the proppant shear behavior of these proppants after fracture closure using a Large Sample Rig to perform triaxial shear experiments. The experiments were at ambient temperature and constant confining pressure of 50Mpa analog to a typical minimum horizontal stress. The fracture geometry is pre-defined through a saw-cut on the Eagleford core sample. The proppants are placed at a gouge thickness of about 2mm to represent the fracture width. The resulting stick-slip during the proppant shearing is the analog for earthquake potential. The energy released during shearing of these proppants is up-scaled to field level at varying shear active fracture lengths. This is to determine the magnitude of a likely earthquake should this mechanism occur in the subsurface. We also tested the replicability/reactivating nature of these events by slide-hold-slide tests during the shearing experiments. The microscopic deformation of proppants and indentation on the Eagle-ford cores were observed. The energy released depends on the minimum horizontal stress, shear active fracture length, slip rate, and proppant type. 1. INTRODUCTION Several works of literature have reported the occurrence of earthquakes around hydraulic fracturing active areas like Texas and Oklahoma, Alberta (Hui et al. 2020, Julie E. et al. 2019, Kumar et al. 2019). The common notion so far is that these seismic events are largely due to the injection of fracturing fluids within pre-existing fault lines, and the disposal of wastewater. Julie E. et al. (2019) reported about 333 wells with hydraulic fracturing-related seismicity after reviewing the "Frac Notice-Seismicity Match Catalog" for a three-year period. They identified 960 earthquakes with magnitude ≥ 2 in the catalog and about 6% of these earthquakes ≥ 3. The largest earthquake associated with a well completion had a magnitude of 3.9. The catalog is based on well seismicity matches using earthquakes that occurred within 5 Km of a well and between the initiation of hydraulically fracturing a well and seven days after the commencement of well flow back as a criterion. There are common observations of wellbore damage either by collapse or shearing especially along horizontal well laterals as a result of formation compaction, subsidence, or movement. This introduces the probability of shearing along already closed hydraulic fractures or pre-existing fault lines. The subsequent release in energy from this mechanism could be a potential contributor to the magnitude of earthquakes resulting from hydraulic fracturing and its related operations.
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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 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 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 ».