The most important resources to fulfill today’s energy demands are fossil fuels, such as oil and natural gas. When exploiting hydrocarbon reservoirs, a detailed and credible model of the subsurface structures to plan the path of the borehole, is crucial in order to minimize economic and ecological risks. Before that, the placement, as well as the operations of oil rigs need to be planned carefully, as off-shore oil exploration is vulnerable to hazards caused by strong currents. The oil and gas industry therefore relies on accurate ocean forecasting systems for planning their operations. This thesis presents visual workflows for creating subsurface models as well as planning the placement and operations of off-shore structures. Creating a credible subsurface model poses two major challenges: First, the structures in highly ambiguous seismic data are interpreted in the time domain. Second, a velocity model has to be built from this interpretation to match the model to depth measurements from wells. If it is not possible to obtain a match at all positions, the interpretation has to be updated, going back to the first step. This results in a lengthy back and forth between the different steps, or in an unphysical velocity model in many cases. We present a novel, integrated approach to interactively creating subsurface models from reflection seismics, by integrating the interpretation of the seismic data using an interactive horizon extraction technique based on piecewise global optimization with velocity modeling. Computing and visualizing the effects of changes to the interpretation and velocity model on the depth-converted model, on the fly enables an integrated feedback loop that enables a completely new connection of the seismic data in time domain, and well data in depth domain. For planning the operations of off-shore structures we present a novel integrated visualization system that enables interactive visual analysis of ensemble simulations used in ocean forecasting, i.e, simulations of sea surface elevation. Changes in sea surface elevation are a good indicator for the movement of loop current eddies. Our visualization approach enables their interactive exploration and analysis. We enable analysis of the spatial domain, for planning the placement of structures, as well as detailed exploration of the temporal evolution at any chosen position, for the prediction of critical ocean states that require the shutdown of rig operations. We illustrate this using a real-world simulation of the Gulf of Mexico.

This thesis presents a three-dimensional groundwater modeling of Wekia springshed in central Florida using a numerical model, WASH123D. Springs have historically played an important role in Florida's history. The Wekiva River is a spring-fed system associated with about 19 springs connected to the Floridan aquifer. With increased urbanization and population growth in this region, there has been an increased strain on the water levels of Floridan aquifer which is a major source of potable water. Maintaining groundwater recharge to the aquifer is a key factor of the viability of the regional water supply as well as Wekiva ecosystem. Hence, the first-principle, physics-based watershed model WASH123D has been applied to conduct the study of Wekiva "springshed", which is the recharge area and watershed contributing groundwater and surface water to the spring. In this work, the hydrogeologic conditions of the Wekiva springshed are discussed followed by the modeling details such as mathematical background, domain discretization and initial and boundary conditions considered. Finally, the results from the model are discussed. The Wekiva WASH123D model was run to evaluate the average, steady state 1995 hydrological conditions. The distribution of simulated Floridan aquifer system groundwater levels using WASH123D shows very good agreement with the field observations at corresponding locations.

<p>Extensive assemblages of glacial erosional features are commonly observed on bedrock outcrops in deglaciated landscapes. There is considerable debate regarding the origins of many subglacial erosional landforms, due to a relative paucity of detailed data concerning these features and a need for improved understanding of the subglacial processes that may form them. This study presents detailed documentation and maps of assemblages of glacial erosional features from select field sites throughout the Great Lakes basins. The characteristics and spatial distribution of p-forms exposed on variable substrates at the Whitefish Falls, Vineland, Pelee Island and Kelleys Island field sites were investigated in order to determine the mode of p-form origin to identify significant spatial and temporal variability in subglacial processes operating at these locations. Observations from this work suggest that p-forms evolve through multiple phases of erosion, whereby glacial ice initially abrades the bedrock surface, leaving behind streamlined bedrock highs, striations and glacial grooves. Subsequent erosion by vortices in turbulent subglacial meltwater sculpts the flanks of bedrock highs and grooves into p-forms. These forms are subjected to a second phase of subglacial abrasion that ornaments the sinuous, sharp rimmed features with linear striae. The presence of multi-directional (‘chaotic’) striae at some sites suggests erosion by saturated till may contribute to, but is not essential for p-form development. Investigation in the Halton Hills region of Ontario focused on modeling bedrock topography in order to delineate the extent and geometry of buried bedrock valleys thought to host potential municipal significant aquifer units. Various approaches to subsurface modeling were investigated in the Halton Hills region using a combination of primary data (collected from boreholes and outcrop), intermediate data collected through aerial photography and consultant reports, and extensively screened low quality data from the Ontario Waterwell Database. A new, ‘quality weighted’ approach to modeling variable quality data was explored but proved ineffective for the purposes of this study, as differential weighting of high and low quality data either over-smoothed the model or significantly altered data values. A series of models were interpolated and compared using calculated RMSE values derived from model cross-validation. The preferred bedrock topography model of the Halton Hills region had the lowest RMSE score, and allowed identification of three major buried bedrock valleys systems (the Georgetown, Acton and 16 Mile Creek buried valleys) which contain up to 40 – 50 m of Quaternary infill. These valleys were likely carved through a combination of fluvial and glacial erosion during the late Quaternary period, and their orientation may be influenced by pre-existing structural weaknesses in the bedrock. Future work on subglacial erosional landforms should focus on the temporal scale in which subglacial processes, through association with other subglacial landforms and dating methods.</p> / Master of Science (MSc)

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