<p> Integrated analysis of well and geophysical data can provide detailed geologic interpretation of the subsurface in Osage County, Oklahoma. Systems tracts and depositional system successions can be interpreted at marginal seismic resolution using well log motif with seismic reflector character within a depositional context. Shelf-prism and subaqueous, delta-scale clinoforms of Missourian age observed in 3D seismic were interpreted with greater sequence stratigraphic detail when coupled with wireline well logs. The Late Pennsylvanian Midcontinent Sea was thought to be approximately 150 feet average depth across the southern Midcontinent during the Missourian Stage, and deepen towards the Arkoma and Anadarko Basins to the south. Here we show that the Late Pennsylvanian Midcontinent Sea floor was in water depths greater than 600 feet and sloped to the southeast, toward major, southern basins, during the Missourian Stage in Osage County. Shelf-prism and delta scale clinoforms up to 600 and 300 feet of relief, respectively, were observed in paired seismic and well log cross sections, thickness maps, and structure maps dipping northwest at 052&deg; strike, upon a basin floor dipping southeast at 253&deg; strike. Lithologic and sequence stratigraphic interpretation revealed a mixed carbonate-siliciclastic system comprising of delta, offshore shelf, and carbonate buildup depositional systems of mesothem, 3rd order sequence magnitude. The observed succession included: 1) falling stage to lowstand, sand-prone, subaqueous delta, 2) transgressive to highstand offshore shelf and carbonate bank, and 3) falling stage delta. The depositional sucession demonstrates how carbonate banks related spatially to terrigenous sediment input in northeastern Oklahoma during the Late Pennsylvanian because of glacio-eustasy and possible tectonism.</p><p>

<p> The Tuscaloosa Marine Shale (TMS) in southwest Mississippi and south-central Louisiana has potential to become a prolific source of fossil fuels using hydraulic fracturing technology. The objective of this study is to better understand the sequence and regional stratigraphy, lithology, and character of the TMS. Studying the TMS&rsquo;s lithologic, depositional, and diagenetic properties is essential to maximize potential production. Characterization of the eastern TMS was performed with cuttings from two wells provided by the Mississippi Oil and Gas Board through MDEQ, and two provided by the USGS. Thirty-one petrophysical logs were correlated, to make cross sections and trace sequence stratigraphic intervals within the TMS. Results of the study showed lithologic variability and compaction across the study area, and a sequence stratigraphic correlation of the highstand systems track between the Tuscaloosa and Eagle Ford Groups. This research aims to work toward the greatest potential of the TMS as an unconventional reservoir.</p><p>

The “Policy Framework for Iraq’s Petroleum Industry” is a logical structure that establishes the rules to guide decisions and manage processes to achieve economically efficient outcomes within the energy sector. It divides policy applications between regulatory and regulated practices, and defines the governance of the public sector across the petroleum industry and relevant energy portfolios. In many “Rentier States” where countries depend on a single source of income such as oil revenues, overlapping powers of authority within the public sector between policy makers and operators has led to significant conflicts of interest that have resulted in the mismanagement of resources and revenues, corruption, failed strategies and the ultimate failure of the system. Some countries have succeeded in identifying areas for progressive reform, whilst others failed due to various reasons discussed in this thesis. Iraq fits into the category of a country that has failed to implement reform and has become a classic case of a rentier state. The primary aim of this research is to produce a policy framework applicable to the local settings of Iraq’s petroleum industry, together with an implementation strategy that helps the country in its transition from legacy practices to sustainable policies compatible with the federal constitution of 2005. Such a framework would observe the legislative applications that appeared in the aftermath of establishing a federal regime. The framework will help to rationalise the decisions and processes that sustain the governance and business practices across the energy value chain of Iraq. The development of a policy framework exemplified by the final setting of the Federal Energy Council (FEC) proposed in this thesis has to take into account the existing legal framework, the legacy of previous policies and the governance arrangements of developing policy under a new federal regime. A review of federal models of major resource holders that may share similar attributes to Iraq is subsequently necessary to identify the appropriate fiscal regime which fits Iraq’s legal system. Conflicts of interest and how they have been reduced or eliminated in case study countries, must be identified to instruct the final proposed framework. This research also examines key factors that influence the petroleum sector of a federalized major resource holder. Furthermore, qualitative in-depth case studies have been conducted to investigate the research problem. This research is complemented by numerous interviews that took place with high profile executives, policy makers and senior officials, as well as a review of data relevant to Iraq from an array of historical literature. The findings of this thesis will comprise a proposed “policy framework for Iraq’s petroleum industry,” exemplified by the FEC that the federal government of Iraq needs to adopt to transition energy institutions from the legacy of centralised rule to a modern and efficient petroleum industry in a democratic setting.

<p> Over the past 70 years the Mississippian strata of Northwest Arkansas have been studied in great detail. The study area is located on the escarpment between the Boston Mountains Plateau and the Springfield Plateau where a surface occurrence of Mississippian age rock allows for access to outcrops in close proximity to gas wells that encounter subsurface Mississippian strata. Many outcrops found in Northwest Arkansas expose Lower Mississippian (Kinderhookian-Osagean) strata that represent a full third order transgressive/regressive sequence that is unconformity bounded. These Mississippian outcrops are commonly treated as surface analogs to the Mississippi Lime Play in North Central Oklahoma. This thesis focuses on the analysis of Boone tripolitic chert in the subsurface utilizing wireline data available from selected gas wells within the study area. The primary goal of this project is to determine and quantify the subsurface stratigraphic position of tripolitic chert from wells that cut a complete section of the Boone Formation. 24 of the 27 (89%) wells within the study with bulk density logs penetrated a substantial section of the Boone Formation and confirmed the presence of tripolite through a density value less than 2.1 g/cc. </p><p> Analysis of wireline data from selected wells is used to characterize the Mississippian system with a specific focus on the distribution of tripolitic chert. Correlation of Mississippian gas production to tripolitic chert occurrence along with the correlation of subsurface data with outcrop data are secondary objectives.</p><p>

Made available in DSpace on 2014-06-11T19:26:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-07-08Bitstream added on 2014-06-13T20:54:22Z : No. of bitstreams: 1 oliveira_w_me_rcla.pdf: 461967 bytes, checksum: c920390365a5f97cdc0f17a5137e0eda (MD5) / Por possuir composição química complexa a água produzida de petróleo pode ser potencialmente tóxica ao meio ambiente. O Ba é um dos elementos presentes nesta água. Por este motivo a técnica DGT é extremamente viável para determinação da fração lábil desse metal. Foi utilizado a membrana difusiva 3MM e como agente ligante a membrana P81. Foram conduzidos experimentos em soluções-padrão para estabelecer o coeficiente de difusão de Ba na membrana difusiva e os efeitos das principais variáveis da técnica em relação ao tipo de amostra a ser analisada como tempo de imersão, salinidade e pH. Para determinação do Ba, amostrados pelos dispositivos DGT foi utilizada a técnica espectrometria de emissão óptica com plasma acoplado indutivamente. Após a determinação dos parâmetros necessários o método desenvolvido foi aplicado para análise das amostras de água produzida oriundas de regiões de produção on shore e off shore da Petrobras. O procedimento desenvolvido foi efetivo para determinação do elemento em amostras originárias de extração on shore (onde a salinidade não exerceu fator interferente) e off shore neste caso, limitado a uma imersão de 4 horas e com a utilização de Coeficiente de Difusão aparente que corrige o efeito da salinidade. A utilização da água produzida na irrigação, considerando-se a concentração de Ba, fica restrita às amostras on shore por possuírem teores de Ba coerentes com a legislação / Due to the complex chemical composition of oil produced water it can be potentially toxic to the environment. The Ba is one of the elements present in this water. For this reason the DGT technique is extremely viable to determine the labile fraction of this metal. Diffusive membrane 3MM was used as diffusive agent and P81 was used as chelating agent. Experiments were carried out on standard solutions to establish the diffusion coefficient of Ba on the membrane and the diffusive effects of the main variables of the technique in relation to the type of sample being considered, as immersion time, salinity and pH. For determination of Ba, sampled by DGT devices the technique of optical emission spectrometry with inductively coupled plasma was used. After determining the required parameters the developed method was applied to analyze the water produced samples from production areas of Petrobras on shore and off shore. The procedure developed was effective for determining the element extraction in samples originating on shore (where the salinity did not have such interference) and off shore, in this case limited to 4 hours of immersion and the use of apparent diffusion coefficient that suits the effect of salinity. The use of water produced in irrigation, considering the concentration of Ba, is restricted to samples on shore because they have levels of Ba consistent with the legislation

<p> The informally known &ldquo;Mississippian Limestone&rdquo; stratigraphic interval in north-central Oklahoma, U.S.A. bears no chronostratigraphic markers and has no formally established biostratigraphic framework to date. Conodonts collected from four &ldquo;Mississippian Limestone&rdquo; cores in Logan, Payne, and Lincoln Counties provide the means for better constraining the stratigraphic age of the interval over the area studied. Conodont extraction was conducted by acid digestion of whole-rock samples and heavy liquid density separation after which conodont genera and species types were identified from scanning electron microscopy. Biostratigraphically significant conodonts recovered in combination with chemostratigraphic work by Dupont (2016) and earlier studies by Thornton (1958), Curtis and Chaplin (1959), McDuffie (1959), Rowland (1964), Selk and Ciriacks (1968), and Harris (1975) indicate the &ldquo;Mississippian Limestone&rdquo; ranges from middle Osagean to late Chesterian in age. In general, conodont element recoveries were too low in quantity and too poor of quality for use as biostratigraphic markers. The relatively low recovery and poor preservation quality of the conodont elements are attributed primarily to the elements being reworked soon after deposition by frequent storms on a mid- to outer-ramp environment in a low-latitude carbonate ramp setting. The results of this investigation are most significant in that they help place Mississippian deposition over the area studied within the context of a global Carboniferous stratigraphy. The results also allow for the Mississippian interval in the study area to be more accurately related to time-correlative strata with similar or better age constraint for constructing more temporally meaningful depositional models of the Oklahoma basin.</p><p>

<p> Hydrocarbon recovery rates within the Niobrara Shale are estimated as low as 2&ndash;8%. These recovery rates are controlled by the ability to effectively hydraulic fracture stimulate the reservoir using multistage horizontal wells. Subsequent to any mechanical issues that affect production from lateral wells, the variability in production performance and reserve recovery along multistage lateral shale wells is controlled by the reservoir heterogeneity and its consequent effect on hydraulic fracture stimulation efficiency. Using identical stimulation designs on a number of wells that are as close as 600ft apart can yield variable production and recovery rates due to inefficiencies in hydraulic fracture stimulation that result from the variability in elastic rock properties and in-situ stress conditions. </p><p> As a means for examining the effect of the geological heterogeneity on hydraulic fracturing and production within the Niobrara Formation, a 3D geomechanical model is derived using geostatistical methods and volumetric calculations as an input to hydraulic fracture stimulation. The 3D geomechanical model incorporates the faults, lithological facies changes and lateral variation in reservoir properties and elastic rock properties that best represent the static reservoir conditions pre-hydraulic fracturing. Using a 3D numerical reservoir simulator, a hydraulic fracture predictive model is generated and calibrated to field diagnostic measurements (DFIT) and observations (microseismic and 4D/9C multicomponent time-lapse seismic). By incorporating the geological heterogeneity into the 3D hydraulic fracture simulation, a more representative response is generated that demonstrate the variability in hydraulic fracturing efficiency along the lateral wells that will inevitability influence production performance. </p><p> Based on the 3D hydraulic fracture simulation results, integrated with microseismic observations and 4D/9C time-lapse seismic analysis (post-hydraulic fracturing &amp; post production), the variability in production performance within the Niobrara Shale wells is shown to significantly be affected by the lateral variability in reservoir quality, well and stage positioning relative to the target interval, and the relative completion efficiency. The variation in reservoir properties, faults, rock strength parameters, and in-situ stress conditions are shown to influence and control the hydraulic fracturing geometry and stimulation efficiency resulting in complex and isolated induced fracture geometries to form within the reservoir. This consequently impacts the effective drainage areas, production performance and recovery rates from inefficiently stimulated horizontal wells. </p><p> The 3D simulation results coupled with the 4D seismic interpretations illustrate that there is still room for improvement to be made in optimizing well spacing and hydraulic fracturing efficiency within the Niobrara Formation. Integrated analysis show that the Niobrara reservoir is not uniformly stimulated. The vertical and lateral variability in rock properties control the hydraulic fracturing efficiency and geometry. Better production is also correlated to higher fracture conductivity. 4D seismic interpretation is also shown to be essential for the validation and calibration hydraulic fracture simulation models. The hydraulic fracture modeling also demonstrations that there is bypassed pay in the Niobrara B chalk resulting from initial Niobrara C chalk stimulation treatments. Forward modeling also shows that low pressure intervals within the Niobrara reservoir influence hydraulic fracturing and infill drilling during field development.</p><p>

Orientador: Carlos Alberto Luengo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-10T20:21:36Z (GMT). No. of bitstreams: 1 Perdomo_LeonardoVerbicaro_M.pdf: 1471442 bytes, checksum: 55995a35994cc8df5ffc69d4d28c5d2f (MD5) Previous issue date: 2008 / Resumo: Nesta dissertação é apresentada uma análise de problemas da mecânica da fratura elástica linear em estruturas bimateriais anisotrópicas. Utilizando o método dos elementos de contorno é possível calcular os fatores de intensidade de tensão em problemas planos (2D) devido à presença de trincas interfaciais entre as lâminas que compõem o material. A estrutura pode estar submetida à carregamento em modo I ou modo misto. O problema é modelado usando-se a técnica de sub-regiões para descrever cada um dos diferentes subdomínios, representado por cada material. Na interface das sub-regiões, em que o domínio é dividido, são impostas condições de equilíbrio de forças e continuidade de deslocamentos, exceto na região que corresponde à trinca. O comportamento singular apresentado pelo campo de tensões próximo à ponta da trinca é modelado com elementos de ponto a um quarto com singularidade de forças de superfície. São apresentados exemplos numéricos de problemas com carregamentos no plano. Foi também apresentada a análise de convergência de malhas, mostrando uma pequena dependência da discretização mesmo quando malhas pouco refinadas foram usadas. Alguns dos exemplos têm correspondentes na literatura, os quais foram utilizados para comparação com os resultados obtidos. Observou-se uma boa concordância na comparação dos resultados / Abstract: This thesis presents an analysis of problems of linear elastic fracture mechanics in anisotropic bimaterial structures. Using the boundary element method, it is possible to evaluate stress intensity factors in plane problems (2D) due to the presence of interfacial cracks between the laminae that constitute the material, when the structure is submitted to a mode I or in mixed mode loading. The problem is modeled using the subregion technique to describe each one of the different subdomains, represented by each material. On the interface of subregions, which the domain is divided, conditions of tractions equilibrium and displacements continuity are imposed, except in the corresponding crack region. The singular behavior presented by the stress field near the crack tip is modeled by traction singular quarter point element. Numerical examples of problems with in-plane loading are presented. Mesh convergence analyses are also presented, showing little dependence on the discretization even when coarse meshes were used. Some of these examples have correspondents in literature, that were used for comparisons with the obtained results. A good agreement in the comparisons of results was observed / Mestrado / Planejamento de Sistemas Energeticos / Mestre em Engenharia Mecânica

<p> In this study, several efficient and accurate mathematical models and numerical solutions to unconventional reservoir development problems are developed. The first is the three-dimensional embedded discrete fracture method (3D-EDFM), which is able to simulate fluid flow with multiple 3D hydraulic fractures with arbitrary strike and dip angles, shapes, curvatures, conductivities and connections. The second is a multi-porosity and multi-physics fluid flow model, which can capture gas flow behaviors in shales, which is complicated by highly heterogeneous and hierarchical rock structures (ranging from organic nanopores, inorganic nanopores, less permeable micro-fractures, more permeable macro-fractures to hydraulic fractures). The third is an iterative numerical approach combining the extended finite element method (X-FEM) and the embedded discrete fracture method (EDFM), which is developed for simulating the fluid-driven fracture propagation process in porous media. </p><p> Physical explanations and mathematical equations behind these mathematical models and numerical approaches are described in detail. Their advantages over alternative numerical methods are discussed. These numerical methods are incorporated into an in-house program. A series of synthetic but realistic cases are simulated. Simulated results reveal physical understandings qualitatively and match with available analytical solutions quantitatively. These novel mathematical models and computational solutions provide numerical approaches to understand complicated physical phenomena in developing unconventional reservoirs, thus they help in the better management of unconventional reservoirs. </p><p>

M.Sc.