Deposition, stratigraphy, provenance, and reservoir characterization of carbonate mudstones: the Three Forks Formation, Williston Basin
Notice bibliographique
Résumé
This thesis uses a drill core database from a 250 square mile area of North Dakota and Montana to evaluate the depositional environment, stratigraphic development, provenance, and reservoir quality of the Famennian Three Forks carbonate mudstones.Depositional environments and lithofacies include the following.Schizohaline, storm dominated intrashelf deposits defined by disturbed claystone, dolomudstone, sandstone, laminated mudstone, and distorted to brecciated dolomudstone lithofacies.These lithofacies often contain syneresis cracks, desiccation cracks, high depositional rate features such as convolute bedding and load features, and many scours.Ichnofacies vary from fairweather mobile and sessile feeding traces, early post-storm event escape traces, post-event opportunistic colonizers, and a final return to fairweather colonies.Arid shallow shelf deposits form during times of minimal fluvial and resultant minimal siliciclastic input into the basin, as well as times of evaporation conducive to broad salina, evaporative gypsum deposits.Mudflats rim these two shelf environments.During arid times they commonly contain abundant syndepositional nodular anhydrites and during less arid times they are full of intraclasts that range in abundance and size.Significant autogenic organization of these deposits is inferred to result in high frequency facies variability due to geomorphologic buildups.A major allogenically controlled shift progresses upwards in the stratigraphy as the deposits decrease in evidence of aridity and increase in evidence of fluvial inputs.Detailed correlations and calibrations to regional biostratigraphic studies delineate seven third-order transgressive-regressive cycles within the formation.Calibration to the biostratigraphic timescale facilitates comparison of 87 Sr/ 86 Sr data to eustatic trends.These data indicate freshwater inputs that also provide more radiogenic Sr than the well-mixed global curve.Additionally δ 34 S values across chronostratigraphically equivalent Famennian deposits in western North America corroborate this conclusion.Quantitative mineralogy trends, siliciclastic grain size comparisons, and ε Nd values support a primary fluvial system of sediments derived and progressively recycled from the Ellesmerian and Caledonian orogens north of the Canadian Shield as the primary siliciclastic sources.Some petrographic trends however do suggest some ephemeral drainage behavior from multiple directions surrounding the basin.Gypsum converted to anhydrite was precipitated directly from the fluvially-modified seawater indicated by radiogenically enriched 87 Sr/ 86 Sr values.Dolomites predominantly formed as automicrites through freshwater mixing and meso-to hypersaline reflux based on elevated 87 Sr/ 86 Sr values, fluvial input evidence including syneresis and sand pulses, ichnofacies and bedded evaporites.Automicrite nucleated through biological processes attributed to unique chemical conditions in the intrashelf basin.Details regarding the geologic formation of these rocks have significant implications for understanding controls on reservoir matrix characteristics.Heterogeneous samples with smaller grain sizes, variable sedimentary structures, or clay mottles consistently have superior reservoir quality than larger siliciclastic grain sizes, or homogenous textured samples.Subtle differences in pore sizes, shapes and resultant interconnectivity determine the potential for matrix oil saturation.Mercury porosimetry and nitrogen adsorption and desorption data indicate that for oil saturation to occur in this formation the reservoir matrix requires either high volumes of moderately sized iv nanopores with moderate connectivity or a moderate volume of large nanopores with some connectivity.Oil saturations in matrix with reservoir bitumen or in poor matrix quality that does not meet these criteria may be difficult to actually produce.
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 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 | 0,001 | 0,001 |
| 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 ».