The facies architecture and geometry of stratigraphic surfaces within a lignite bearing interval of the Paleocene upper Calvert Bluff Formation is mapped on a photomosaic of the 150 ft (50 m) high and 12,000 ft (4km) long “C” area highwall of Big Brown Mine, near Fairfield, Texas. Observed bedding and facies architecture are interpreted in terms of temporal changes, depositional environments and sequence stratigraphic setting. A three dimensional grid of 89 subsurface logs is correlated to this photomosaic to characterize log response patterns of facies. Six facies are observed: 1) lignite, 2) interdistributary bay mud, 3) prograding delta, 4) delta top mud, 5) distributary channels, and 6) incised valley fill. The six facies were defined by a combination of mapped photomosaic observations and subsurface log correlations. The lignite deposit formed in a low depositional energy, low sediment input, high-organic productivity interchannel basin. Overlying mud records overbank flooding followed by avulsion and progradation of delta deposits. Tidal-flat deposits overlying prograding delta deposits record fluctuating energy conditions on the emerging delta top. Channel deposits cutting into the delta top record lateral channel migration across delta top floodplains. These regressive delta deposits are capped by a local incised sequence boundary overlain by fluvial channel deposits inferred to have allowed sediment to bypass further basinward during lowstand. A sheet of channel deposits capping this highwall exposure records more recent erosion, followed by development of modern soil horizons. The Big Brown Mine highwall exposes a relatively complete high-frequency Paleocene stratigraphic sequence developed in an area landward of the shoreline position during maximum transgression, that progresses upsection from: 1) highstand alluvial flood basin coals, 2) a thin condensed maximum flooding interdistributary shale, 3) a thick succession of regressive deltaic strata, and 4) a high-relief, sequence-bounding erosion surface overlain by a lowstand to transgressive fill of channel deposits. Correlations with regional Wilcox Group stratigraphic studies spanning coeval shoreline and shelf strata indicate that this high-frequency sequence is within the transgressive systems tract of a 3rd order stratigraphic sequence. It appears that high-frequency sequences of sub-regional extent control the complex distribution of coal seams within central Texas.

Thesis (Ph.D.), Memorial University of Newfoundland, 2000. / Restricted until June 2001. Bibliography: leaves 212-234. Also available online.

This thesis introduces a rock typing method for application in shale gas reservoirs using conventional well logs and core data. Shale gas reservoirs are known to be highly heterogeneous and often require new or modified petrophysical techniques for accurate reservoir evaluation. In the past, petrophysical description of shale gas reservoirs with well logs has been focused to quantifying rock composition and organic-matter concentration. These solutions often require many assumptions and ad-hoc correlations where the interpretation becomes a core matching exercise. Scale effects on measurements are typically neglected in core matching. Rock typing in shale gas provides an alternative description by segmenting the reservoir into petrophysically-similar groups with k-means cluster analysis which can then be used for ranking and detailed analysis of depth zones favorable for production. A synthetic example illustrates the rock typing method for an idealized sequence of beds penetrated by a vertical well. Results and analysis from the synthetic example show that rock types from inverted log properties correctly identify the most organic-rich model types better than rock types detected from well logs in thin beds. Also, estimated kerogen concentration is shown to be most reliable in an under-determined problem. Field cases in the Barnett and Haynesville shale gas plays show the importance of core data for supplementing well logs and identifying correlations for desirable reservoir properties (kerogen/TOC concentration, gas saturation, and porosity). Qualitative rock classes are formed and verified using inverted estimates of kerogen concentration as a rock-quality metric. Inverted log properties identify 40% more of a high-kerogen rock type over well-log based rock types in the Barnett formation. A case in the Haynesville formation suggests the possibility of identifying depositional environments as a result of rock attributes that produce distinct groupings from k-means cluster analysis with well logs. Core data and inversion results indicate homogeneity in the Haynesville formation case. However, the distributions of rock types show a 50% occurrence between two rock types over 90 ft vertical-extent of reservoir. Rock types suggest vertical distributions that exhibit similar rock attributes with characteristic properties (porosity, organic concentration and maturity, and gas saturation). This method does not directly quantify reservoir parameters and would not serve the purpose of quantifying gas-in-place. Rock typing in shale gas with conventional well logs forms qualitative rock classes which can be used to calculate net-to-gross, validate conventional interpretation methods, perform well-to-well correlations, and establish facies distributions for integrated reservoir modeling in hydrocarbon-bearing shale. / text

No description available.

Seismic attributes are a descriptive and quantifiable characteristic of seismic data, and so they represent subsets of the total information contained in the original seismic data. Consequently, seismic attrjbutes can be important qualitative and quantitative predictors of physical reservoir properties. Seismic attribute analysis began with the search for bright spots in the late 1960s and early 1970s. Subsequent work in the last decades has established seismic attribute analysis as a valuable tool in reservoir characterization studies. I present in this thesis two seismic attribute analyses for the interpretation of the characteristics of the seismic trace to predict significant geological features (e.g., lithology, rock properties and/or fluid content). The first study is an example of the applicability of seismic attributes to predict geologic controls on production data in a coal bed methane reservoir. Based on the calibration of log data with seismic data procedure, I defined a window of analysis, from which I computed amplitude, frequency and phase related attributes. Then, I used a quantitative multiattribute analysis to derive a seismic attribute-based model that predicts coal thickness. Thereafter, I used with a curvature attribute analysis with the objective to map subtle structural features and predict areas with enhanced permeability. The integration of production data with results achieved from both attribute analyses indicates that best production is associated with thicker coal and the immediate vicinity to seismically defined structures. [...] / Les attributs sismiques ont comme caractéristique de pouvoir décrire et quantifier les données sismiques, de telle manière qu’ils représentent un sous-ensemble de l’information totale contenue dans les données originales. En conséquence, les attributs sismiques peuvent être d’importants paramètres qualitatifs et quantitatifs des propriétés physiques d’un réservoir. L’analyse d’attributs sismiques a commencé avec la prospection de tâches lumineuses (<< bright spots >>) vers la fin des années 1960 et début des années 1970. Des travaux subséquents pendant les dernières décennies ont permis d’établir l’analyse d’attributs sismiques comme un outil valable lors d’études de caractérisation d’un réservoir. Je présente dans cette thèse deux études d’attributs sismiques pour l’interprétation de la forme de la trace sismique afin de prédire des caractéristiques géologiques significatives tels que: la lithologie, les propriétés des roches et/ou le contenu liquide. La première étude est un exemple de l’application d’attributs sismiques pour prédire des contrôles géologiques sur la production d’un réservoir coalbed methane. D’après les résultats de la calibration des diagraphies au câble avec des données sismiques, j’ai défini une fenêtre d’investigation à partir de laquelle des attributs sismiques de type amplitude, fréquence et phase ont été calculés. J’ai utilisé une analyse muIti-attribut pour dériver un model statistique dans le but d’estimer l’épaisseur du réservoir. Par la suite, j’ai utilisé des attributs mesurant la courbature d’une surface pour mettre en relief de subtiles structures géologiques et prédire les régions dans le réservoir avec une perméabilité augmentée. L’intégration des données de production avec les résultats obtenus lors d’analyses d’attributs sismiques indique que la meilleure production est en association avec l’épaississement du réservoir et le voisinage immédiat de structures géologiques. [...]

No description available.

The Upper Devonian-Lower Carboniferous Bakken Formation is present in the subsurface of the Williston Basin in northeastern Montana, North Dakota, southwestern Manitoba and southern Saskatchewan. In the southeastern corner of Saskatchewan, the Bakken Formation either conformably overlies the Upper Devonian Big Valley Formation or unconformably overlies the Torquay Formation, and is conformably overlain by the Lower Carboniferous Souris Valley (Lodgepole) Formation. The Bakken Formation typically includes three members: the lower and upper organic-rich black shale, and the middle calcareous/dolomitic sandstone and siltstone, which makes a “perfect” petroleum system including source rock, reservoir, and seal all within the same formation. According to detailed core analysis in the southeastern corner of Saskatchewan, the Bakken Formation is divided into eight facies, and one of which (Facies 2) is subdivided into two subfacies: Facies 1 (planar cross-stratified fine-grained sandstone); Facies 2A (wavy- to flaser-bedded very fine-grained sandstone); Facies 2B (thinly parallel-laminated very fine-grained sandstone and siltstone); Facies 3 (parallel-laminated very fine-grained sandstone and muddy siltstone); Facies 4 (sandy siltstone); Facies 5 (highly bioturbated interbedded very fine-grained sandstone and siltstone); Facies 6 (interbedded highly bioturbated sandy siltstone and micro-hummocky cross-stratified very fine-grained sandstone); Facies 7 (highly bioturbated siltstone); and Facies 8 (black shale). Our integrated sedimentologic and ichnologic study suggests that deposition of the Bakken occurred in two different paleoenvironmental settings: open marine (Facies 4 to 8) and brackish-water marginal marine (Facies 1 to 3). The open-marine facies association is characterized by the distal Cruziana Ichnofacies, whereas the brackish-water marginal-marine facies association is characterized by the depauperate Cruziana Ichnofacies. Isochore maps shows that both open-marine and marginal-marine deposits are widely distributed in this study area, also suggesting the existence of a N-S trending paleo-shoreline. The Bakken strata in this study area represent either one transgressive systems tract deposits or two transgressive systems tracts separated by a coplanar surface or amalgamated sequence boundary and transgressive surface. This surface has been identified in previous studies west-southwest of our study area, therefore assisting in high-resolution correlation of Bakken strata.

The Middle Devonian formations to be studied in this paper are the Jeffersonville and North Vernon Limestones. Together these formations make up the Muscatatuck Group in the Illinois Basin portion of Indiana. In the area of study, the Jeffersonville Limestone consists from the base upwards of the Geneva Dolomite Member, Vernon Fork Member, and Paraspirifer acuminatus Zone. The North Vernon Limestone consists of the Speed Member overlain by the Beechwood Member.In the study area, the subsurface Muscatatuck Group dips to the southwest at a rate of 20 to 50 feet per mile. These rocks thicken to the southwest, and range in thickness from 136 to 170 feet. Closed-structural highs are present on the top of the Muscatatuck Group over Silurian pinnacle-like reefs.Resistivity log - sonic log cross plots were constructed to analyze the subsurface carbonate facies in the study area. A total of 13 cross plots were constructed with over 1,490 points plotted.From this study five conclusions can be drawn about the application and usefulness of the cross plot method in analyzing the the surface distribution of carbonate facies. As explained in the text, these conclusions remain valid only when applied to the area of study.The conclusions are as follows:1. The positioning of the point groups on the cross plots is controlled by the amount and type of porosity present in the rocks.2. Due to the diagenetic alteration of the primary porosity in the rocks, the point groups can not be divided into depositional textures or facies.3. In this case, because of the uncomplex nature of the stratigraphy and the ease of correlation of the lithologic units on the logs, the cross plots were not useful in analyzing the subsurface distribution of the carbonate facies in the area.4. The cross plots were useful in checking the accuracy of the log correlations.5. The cross plots may be used to infer lateral porosity changes in the rock units, and possibly variations in the diagenetic alteration within these units.

Glacier facies represent distinct regions of a glacier surface characterized by near surface structure and density that develop as a function of spatial variations in surface melt and accumulation. In post freeze-up (autumn) synthetic aperture radar (SAR) satellite imagery, the glacier ice zone and dry snow zone have a relatively low backscatter due to the greater penetration of the radar signal into the surface. Conversely, the saturation and percolation zones are identifiable based on their high backscatter due to the presence of ice lenses and pipes acting as efficient scatterers. In this study, EnviSat ASAR imagery is used to monitor the progression of facies zones across Devon Ice Cap (DIC) from 2004 to 2011. This data is validated against in situ surface temperatures, mass balance data, and ground penetrating radar surveys from the northwest sector of DIC. Based on calibrated (sigma nought) EnviSat ASAR backscatter values, imagery from autumn 2004 to 2011 shows the disappearance of the ‘pseudo’ dry snow zone at high elevations, the migration of the glacier and superimposed ice zones to higher elevations, and reduction in area of the saturation/percolation zone. In 2011, the glacier and superimposed ice zone were at their largest extent, occupying 92% of the ice cap, leaving the saturation/percolation zone at 8% of the total area. This is indicative of anomalously high summer melt and strongly negative mass balance conditions on DIC, which results in the infilling of pore space in the exposed firn and consequent densification of the ice cap at higher elevations.

Thesis (M.S. - Geosciences)--University of Arizona. / Includes bibliographical references (leaves 43-45).