The increased level of greenhouse gases due to human activity is the main factor for climate change. CO2 is the main constitute among these gases. Subsurface storage of CO2 in geological systems such as coal reservoirs is considered as one of the promising perspectives. Coal can be safely and effectively utilized to both store CO2 and recover CH4. By injecting CO2 into the coal beds, methane is released with CO2 adsorption in the coal matrix and this process is known as enhanced coal bed methane recovery (ECBM). Zonguldak Coal Basin is one of the Turkey&amp / #8217 / s important coal resources. Since the coal seams in Bartin-Amasra field are found relatively deeper parts of the basin comparing to other places, this basin was not studied detailed enough yet. Bartin-Amasra basin was found convenient for enhanced coalbed methane recovery. The lithologic information taken from the Turkish Hard Coal Enterprise (TTK) was examined and the depths of the coal seams and the locations of the wells were visualized to perform a reliable correlation between seams existed in the area. According to the correlations, 63 continuous coal layers were found. A statistical reserve estimation of each coal layer for methane was made by using Monte Carlo simulation method. Uncertainty is an important parameter in risk analysis, for this reason the results were determined at probabilities of P10, P50 and P90. Enhanced coalbed methane recovery was simulated with CMG-GEM module using Coal Layer #26 which has more initial gas in place. The effects of adsorption, cleat spacing, compressibility, density, permeability, permeability anisotropy, porosity and water saturation parameters were examined in enhanced coalbed methane recovery by the simulation runs. The initial methane in place found in all these coal layers both in free and adsorbed states were estimated using probabilistic calculations resulted in possible reserve (P10) of 72.97 billion scf, probable reserve (P50) of 47.74 billion scf and proven reserves (P90) of 30.46 billion scf. Since the Amasra coal reservoir is not saturated with water, almost 10% of the total gas in place was found to be in the cleats as free gas. Coal layer #26 has an area of 4099 acres, average thickness of 6.23 ft and depth of 545 m (Karadon formation). P50 reserve estimation was 6.47 billion scf in matrix and 0.645 billion scf in fracture. Although the decrease in cleat porosity was less when shrinkage and swelling effects included, the decrease in cleat permeability as a function of porosity diminished the methane production. Cumulative methane production was enhanced with the injection of carbon dioxide (ECBM) approximately 23% than that of CBM recovery. Although closing the wells to production because of CO2 breakthrough had a negative effect on methane production initially, there was no difference between ultimate methane productions whether the wells remained open or closed, but more carbon dioxide was sequestered when the production ceased at the wells. Injected carbon dioxide amount of 5192 tonnes/year in base case was only capable to sequester only 0.3% of the yearly carbon dioxide emission of Zonguldak &Ccedil / atalagzi Power Plant nearby. Considering the gas in place capacity of the coal layer #26 as 15% of the resource area-A, it can be said that the project aiming ECBM recovery rather than carbon dioxide sequestration would be successful. In spite of water saturated coal reservoirs where the water production is required initially, it can be possible to start immediately the injection of CO2 with methane production for a dry coal reservoir. Cleat permeability being one of the most crucial parameter in the coal reservoir affected the rate of methane production. The more free gas was found in higher porosity cleat systems. Although the cumulative methane production was increased when the cleat porosity rose, methane recovery percentages were remained almost constant. The lower the cleat spacing the higher the rate of transfer between fracture and matrix was observed. The rate of gas desorption from the coal matrix and subsequent diffusion to both butt and face cleats was higher than the rate of flow in the face cleats, then production was flow-limited, pressure-driven and was defined by Darcy&amp / #8217 / s Law. The cumulative CH4 production was higher when the coal was denser. The change in coal compressibility affected slightly the cleat porosity and therefore the cleat permeability due to the change in reservoir pressure. Langmuir volume is defined as maximum adsorption capacity. Kozlu formation (deeper than Karadon formation) having lower Langmuir volume resulted in higher ultimate recovery because of lower Langmuir pressure than that of Karadon formation. In base case (Karadon formation), although the higher Langmuir volume was used, less methane production was observed. Permeability anisotropy generated the CO2-CH4 front in elliptic shape.

Numerical reservoir simulation has been used to describe mechanism of methane gas desorption process, diffusion process, and fluid flow in a coalbed methane reservoir. The reservoir simulation model reflects the response of a reservoir system and the relationship among coalbed methane reservoir properties, operation procedures, and gas production. This work presents a procedure to select the optimum well spacing scenario by using a reservoir simulation. This work uses a two-phase compositional simulator with a dual porosity model to investigate well-spacing effects on coalbed methane production performance and methane recovery. Because of reservoir parameters uncertainty, a sensitivity and parametric study are required to investigate the effects of parameter variability on coalbed methane reservoir production performance and methane recovery. This thesis includes a reservoir parameter screening procedures based on a sensitivity and parametric study. Considering the tremendous amounts of simulation runs required, this work uses a regression analysis to replace the numerical simulation model for each wellspacing scenario. A Monte Carlo simulation has been applied to present the probability function. Incorporated with the Monte Carlo simulation approach, this thesis proposes a well-spacing study procedure to determine the optimum coalbed methane development scenario. The study workflow is applied in a North America basin resulting in distinct Net Present Value predictions between each well-spacing design and an optimum range of well-spacing for a particular basin area.

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. [...]

The exploration for unconventional energy reserves has rapidly increased over the last five to ten years. Currently, there are a number of companies actively exploring for coalbed methane (CBM) in New Zealand. This study investigates one of these prospects, the subbituminous Huntly coalfield. Coal core was retrieved from the two major seams in the coalfield, the Renown and the Kupakupa. Three coals types were identified (1) bright lustre, non-banded, (2) bright lustre, moderately banded and (3) bright lustre, highly banded. As the degree of banding increases, the average thickness of the vitrain bands increase, the amount of structured vitrinite macerals also increase and the vitrodetrinite content decreases. The Renown seam is predominantly composed of bright non-banded coal while in the Kupakupa seam the more banded coal types are dominant. On average, the Renown seam has both the capacity to hold more gas and has higher gas contents than the stratigraphically lower Kupakupa seam. Additionally, gas content, on average, was found to be highest in intervals of the non-banded coal type and lowest in the highly banded coal type. Cluster analysis found that gas content is associated with hydrogen, volatile matter, calorific value and collodetrinite. As such, gas appears to be preferentially retained/produced in the matrix-dominated material. While not causally linked with gas content, gas holding capacity showed associations with the sporinite, inertodetrinite, funginite and vitrodetrinite; of note, these macerals are highest in the non-banded coal type. Gas holding capacity is thought to be a function of coal texture. Ash yield was found to inversely affect total gas content when ash yield is >10%. Below 10%, it is thought that inorganic elements are organically bound. The small angle scattering analysis indicated that inorganic matter was in the 12.5 Å < r < 125 Å pore size range. The influence of inorganic material was more noticeable in vitrain than matrix samples and is proposed to exist as thin inorganic coatings. Total porosity of the Huntly coal is primarily composed of micropores with macroporosity only contributing a small proportion. In addition, the specific surface area of the coals is also largely contributed by the micropores. Methane holding capacity on a dry, ash-free basis showed positive correlations with both micro- and macroporosity. When methane holding capacity was considered on an ‘as analysed’ basis, correlation was only identified with macroporosity. Possibly gas holding capacity is affected by the presence of moisture blocking access to gas adsorption sites in smaller pores. Considerable variation is present in both gas adsorption and gas desorption results between drill holes, between seams and also within individual seam intersections. Gas adsorption capacity and gas content are used to calculate % saturation for a reservoir, a key assessment parameter. It was found that multiple samples of both gas adsorption capacity and gas content are required to reduce the uncertainty around the calculated % saturation (at least three of each in the current study). Additionally, adsorption isotherm samples need to be collected as fresh as possible to minimize oxidation and moisture loss. Delaying sample analysis was found to result in an overestimation of gas adsorption capacity.

Thesis (Ph. D.)--University of Wyoming, 2006. / Title from PDF title page (viewed on April 11, 2008). Includes bibliographical references.

Thesis (M.S.) -- University of Montana, 2008. / Title from author supplied metadata. Description based on contents viewed on June 20, 2009. ETD number: etd-12192008-143539. Includes bibliographical references.

Thesis (M.S.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains xiii, 149 p. : ill. (some col.), maps. Includes abstract. Includes bibliographical references (p. 149).

Thesis (M.S.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains vi, 41 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 40-41).

Thesis (M.S.)--University of Wyoming, 2008. / Title from PDF title page (viewed on August 6, 2009). Includes bibliographical references (p. 50-54).

Thesis (Ph. D.)--University of Wyoming, 2007. / Title from PDF title page (viewed on Sept. 1, 2009). Includes bibliographical references.