Masters of Science / The Bredasdorp basin is situated off the south coast of the Republic of South Africa, southeast of Cape Town and west-south-west of Port Elizabeth. It covers approximately 18,000 sq. km beneath the Indian Ocean along the southern coast of South Africa, which is in the southwest of Mosselbay. Bredasdorp basin contains South Africa’s only oil and gas production facilities and has been the main focus for oil and gas exploration in South Africa. It is one of the largest hydrocarbon producing block in South Africa, rich in gas and oil prone marine source rocks of kimmeridgian to berriasian age. The wells of interest for this study are located within block 9 which is made up of 13 wells but for this study the focus is only on 3 wells, which are well F-01,F-02 and F-03. The goal of this study is to predict as accurately as possible the areas within and around the sandstone reservoir intervals of these wells with abnormal pressure, using well logs and production test data. Abnormal pore pressure which is a major problem for drillers in the oil industry can cause serious drilling incidents and increase greatly drilling non-production time if the abnormal pressures are not predicted accurately before and while drilling. Petrophysics log analysis was done to evaluate the reservoirs. The intervals of the reservoir are the area of interest.Pore pressure gradient, fracture gradient, pore pressure and fracture pressure model were run. Pressures of about 6078.8psi were predicted around the zone of interest in well F-01, 7861 psi for well F-02 and 8330psi for well F-03. Well F-03 was the most pressured of the three wells. Abnormal pressures were identified mostly at zones above and below the area of interest and predicted pressure values were compared to actual pressure values to check for accuracy.

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A questionnaire survey of municipal water-supply agencies British Columbia, Washington, Oregon, and California was conducted for the purpose of comparing present management policies within and among the regions. Regression techniques were employed in an attempt to determine what factors influence the intensity of recreation occurring on a reservoir or watershed. A search of available literature was made to establish the 'facts' regarding water contamination through recreational use, the transmission of disease through water supplies, and the treatment of water to eliminate bacteria and viruses. The costs involved in the use or non-use of domestic water-supply areas for recreation were examined as were the major arguments for and against recreational use of these areas. The analysis of the questionnaire returns showed that in comparison with British Columbia, the States of Washington, Oregon and California all exhibited a higher level of water-supply management. Secondary uses were most prevalent in California and all of the respondents classifying themselves as 'secondary-use' agencies included recreation as one of the uses. In contrast to the situation in Washington and Oregon, and especially in British Columbia, recreational use in California was primarily a regulated use and very often planned and managed in detailed fashion with strict controls. The regression and correlation analysis showed some statistically significant but very weak relationships. The equations produced accounted for very little of the variation in the dependent variable (recreational-use score) and had very large standard errors of estimate. For the systems analyzed, the intensity of recreation occurring on a reservoir or watershed was related to such agency characteristics as present population served, percentage domestic use, degree of water treatment, average percentage of municipally or agency managed lands, average percentages of forest and shrub covered buffer and watershed lands and recreation opportunity in surrounding areas. From the search of pertinent literature and the questionnaire results, it was established that well planned and managed recreation facilities can be operated in conjunction with domestic water-supply facilities and have minimal effects on raw water quality. The potential hazard of disease transmission through the water system was fully recognized; however, water treatment techniques that will reduce this risk to a minimum are presently, available. On the basis of the research carried out in this study it was concluded that when conducted in accord with an ecologically sound management plan, recreation and the production of high quality potable water are indeed mutually compatible land uses. / Forestry, Faculty of / Graduate

Reservoirs represent a relatively young element of the U.S. landscape, with most reservoirs being built within the last century. Despite their recreational, ecological, and socioeconomic importance, reservoirs nationwide are suffering from severe habitat degradation. Habitat impairments related to siltation, eutrophication, poor water quality, water regime, lack of submerged structure, and macrophyte invasions affect reservoirs to differing degrees in different reservoirs. To adequately assess these issues, we needed to develop a classification system within which an assessment mechanism could function. I collected data for large reservoirs across the conterminous U.S. regarding fish habitat impairments and status of the fish community and recreational fishery. Using these data, I developed a fish habitat classification system for large U.S. reservoirs, which can be used to better understand differences among reservoirs, develop habitat management expectations, and prioritize conservation efforts.

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The second pandemic persisted for 500 years throughout Europe and some regions of Africa and Asia and far surpasses the first and third pandemics in terms of temporal and spatial breadth. It is still unclear what mechanisms facilitated the long-term maintenance and continued disease reintroductions experienced during the second pandemic. Many researchers believe it was the spread of plague infected Rattus spp. via trade routes, while others are beginning to support a model that reflects modern plague ecology such that plague was maintained in local rodent reservoirs in the Mediterranean region or Europe following its 14th century introduction. This study accumulated a list of rodent species known to host plague and analyzed host characteristics to determine what traits allow rodents to function as successful reservoir species. In addition, this study analyzed the ancient DNA within rodent remains in search of Yersinia pestis to add to the history of the pathogen. The results of this study demonstrate that there are 45 non-Rattus rodent species known to host plague within a modern context. Although ancient Y. pestis DNA was not identified from zooarchaeological remains within this study, it is clear that rodent reservoirs were key players in past plague pandemics. When viewed through the lens of a single model (i.e. trade routes or human-ectoparasites), several questions about past plague maintenance remain unanswered. This study shows that a more complex composite model is best fit to describe the 500-year reign of the second pandemic and the quiescent periods that extended between the cyclical disease reintroductions. This study presents the first comprehensive, interactive, and publicly available online database of rodent reservoirs to aid in future research and emphasizes the need to investigate a multi-mechanism model of plague maintenance and reintroduction in the past. With this research we facilitated a starting point for future studies, expanded the current knowledge on rodent reservoirs of plague, and contributed a valuable discussion to the field of plague studies on regions that have thus far gone underserved in plague studies, such as the Mediterranean littoral. / Thesis / Master of Arts (MA)

Injecting CO2 into unconventional reservoirs to enhance oil recovery has been widely studied due to its potential to improve the profitability of these reservoirs. CO2 Huff-n-Puff is emerging as a promising method, but exploiting its full potential is challenging due to difficulties in optimizing its operations. The latter arises from the limited understanding of CO2 and oil transport in unconventional reservoirs. This dissertation used molecular dynamics simulations to study the storage and transport of oil and CO2 in unconventional reservoirs in single nanopores. The first study examined the modulation of oil flow in calcite pores by CO2. It is discovered that CO2 molecules adsorb strongly on calcite walls and can change decane permeability through 8 nm-wide pores by up to 30%. They impede decane flow at moderate adsorption density but enhance flow as adsorption approaches saturation. The second study investigated the CO2 transport in 4 nm-wide calcite pores during the soaking phase of Huff-n-Puff operations. CO2 entering the pore can become adsorbed on pore walls and diffuse on them or diffuse as free CO2 molecules. The accumulation of CO2 follows a diffusion behavior with an effective diffusivity ~50% smaller than bulk CO2. Two dimensionless groups are proposed to gauge the importance of surface adsorption and diffusion in CO2 storage and transport in nanopores. The third study examined the extraction of decane initially sealed in a 4 nm-wide calcite pore through exchange with CO2 and CH4 in a reservoir. The CO2-decane exchange is significantly driven by the evolution of adsorbed oil and gas initially, but a transition to dominance by free oil and gas occurs later; for CH4-decane exchange, the opposite occurs. The net gas accumulation and decane extraction follow the diffusive law, but their effective diffusivities do not always align well with the self-diffusion coefficients of CO2, CH4, and decane in the nanopore. The three studies identified the essential roles of gas/oil adsorption in their net transport in nanopores and, thus, unconventional reservoirs. Delineating these roles and formulating dimensionless groups to gauge their importance help develop better models for enhanced oil recovery from unconventional reservoirs by CO2 injection. / Doctor of Philosophy / Unconventional reservoirs are hydrocarbon-bearing formations with ultralow permeabilities, and they have emerged as a critical source of liquid petroleum production in the United States over the past decade. However, because oil is trapped in nanoscale pores in these reservoirs, the oil recovery rate is low. Therefore, many methods have been developed to enhance the oil recovery from unconventional reservoirs. One of the popular methods is to inject gas into reservoirs to enhance oil recovery. Improving this method's efficacy requires a fundamental understanding of the thermodynamic and transport phenomena underlying its operation is needed. This dissertation used molecular dynamics simulations to study the storage and transport of oil and CO2 in unconventional reservoirs at the single nanopore scale. Three series of studies have been performed to elucidate how CO2 modulates the flow of oil inside nanopores, how CO2 enters a nanopore filled with oil, and how oil is extracted from the nanopore by the ingression of CO2. These studies showed that when CO2 molecules adsorb strongly on a nanopore's walls, they can either enhance or impede the permeation of oil through the pore. The ingression of CO2 into an oil-filled nanopore and the concurrent oil extraction can be described by the same equation for the conduction of heat in one-dimensional objects. The CO2 ingression and oil extraction rates are heavily affected by the adsorption of CO2 and oil on the nanopore's walls. These results highlight the important effects of surface adsorption on the storage and transport of gas and oil in nanopores and, thus, unconventional oil reservoirs. Incorporating these effects into oil recovery models will improve their predictive power, and thus help model-guided optimization of oil recovery.

TOPAZ, which is the Technique for the Optimal Placement of Activities in Zones, was developed to provide the urban planner with a workable tool from which he could determine the best allocation of a set of activities to a set of zones and at the same time minimize cost. The main objective of this research was to determine if TOPAZ could be applied to reservoir recreational planning, and if so, the methodology necessary for its use. An example problem which includes a hypothetical reservoir with six zones and four key recreational activities is posed for the testing of the technique. The four key recreational activities being studied are swimming, picnicking, camping and boating. The model which was developed includes three cost components which are the establishment cost, the road cost and the cost of travel. It is shown that the technique can be a powerful aid to the planner of water based recreational facilities. Not only does the model give the planner a series of near optimal allocations of activities, but by the use of the sensitivity analysis the degree of accuracy to which the data should be collected can be determined, The model is also shown to be useful when applied to non-quantifiable type decisions. The results and a discussion of the results are included along with a discussion of other possible applications of the technique as applied to recreational planning. The planner can refine the model to suit his own particular needs by modifying the data input and the associated constraint set. / Master of Science