One of the main objectives in the Oil & Gas Industry is to constantly improve the reservoir management capabilities by using production optimization strategies that can positively impact the so-called net-present value (NPV) of a given project. In order to achieve this goal the industry is faced with the difficult task of maximizing hydrocarbon production and minimizing unwanted fluids, such as water, while sustaining or even enhancing the reservoir recovery factor by handling properly the fluids at surface facilities. A key element in this process is the understanding of the interactions between subsurface and subsurface dynamics in order to provide insightful production strategies which honor reservoir management surface facility constraints. The implementation of the ideal situation of fully coupling surface/subsurface has been hindered by the required computational efforts involved in the process. Consequently, various types of partially coupling that require less computational efforts are practically implemented. Due to importance of coupling surface and subsurface model on production optimization and taking the advantage of advancing computational performance, this research explores the concept of surface and subsurface model couplings and production optimization. The research aims at demonstrating the role of coupling of surface and subsurface model on production optimization under simple production constraint (i.e. production and injection pressure limit). The normal production prediction runs with various reservoir description (homogeneous-low permeability, homogeneous-high permeability, and heterogeneous permeability) and different fluid properties (dead-oil PVT and lived-oil PVT) were performed in order to understand the effect of coupling level, and coupling scheme with different reservoir descriptions and fluid properties on production and injection rate prediction. The result shows that for dead-oil PVT, the production rate from different coupling schemes in homogeneous and heterogeneous reservoir is less sensitive than lived-oil PVT cases. For lived-oil PVT, the production rate from different coupling schemes in homogeneous high permeability and heterogeneous permeability are more sensitive than homogeneous low permeability. The production optimization on water flooding under production and injection constraint cases is considered here also.

No description available.

This study examines the effects of Pseudomonas aeruginosa (PAO1) biofilm, with a concentration of cells similar to that reported for saturated aquifers, on the transport of poly(acrylic acid) stabilized nanoscale zero valent iron (pnZVI) in 14 cm long, saturated, laboratory packed columns, with ionic strengths (ISs) of 1 and 25 mmol NaCl. With biofilm, the retention of pnZVI increased with higher solution IS, while IS played no role in the retention of nanoparticles without biofilm. However, the Tufenkji-Elimelech correlation equation predicts 5% less pnZVI collisions in biofilm coated columns due to a sixfold reduction of the Hamaker constant. Also, DLVO energy considerations predict the most favorable attachment for uncoated porous media at the higher IS. Reasons for the disagreement between theory and experiment are shown to be due to the non-ideality of the biofilm system. This research indicates that current laboratory studies underestimate nanoparticle transport distances in the subsurface. / Environmental Science

Thesis (M.S. - Hydrology and Water Resources)--University of Arizona, 1989. / Includes bibliographical references (leaves 81-84).

Natural groundwater storage can be improved by constructing a subsurface barrier that is a subsurface dam, in order to capture the subsurface flows and raise the groundwater levels (GWLs) in the sediment layers. Subsurface dams are preferable to surface dams because of lower evaporation, higher functionality, lower cost of construction, lessened risk for contamination and the possibility of utilizing land over the dam. Therefore subsurface dams constitute an affordable and effective method for the sustainable development and management of groundwater resources. The aim of this research project was to develop and test methods for the assessment and location of subsurface dams in water resources management. From previous experiences it has been established that locating suitable sites for construction of subsurface dams plays an important role in the overall success of these dams. Therefore, in order to locate suitable sites, two approaches were followed. The first was the Boolean approach using topographical, geological and landcover data in a geographic information system (GIS) environment for a previously glaciated terrain near Stockholm. The results of the Boolean approach were complemented by a groundwater balance model and a topographic wetness index (TWI). The second approach involved spatial multi-criteria analysis (SMCA) applied to a region with different geological and hydrological conditions. SMCA was applied in Northern Pakistan using factors such as topography, geology, landcover, soil thickness and TWI. Two weighting techniques, the analytic hierarchy process (AHP) and the factor interaction method (FIM), were employed and compared. The Factor removal technique was employed to assess the sensitivity of the model for each factor. Aquifer thickness is an important factor while planning subsurface dams and data regarding the soil thickness is often not available at larger scale. Therefore a simplified regolith model (SRM) was developed for estimating the regolith thickness in previously glaciated terrain with a high frequency of rock outcrops, based on a digital elevation model (DEM) and an optimized outcrop search algorithm. In order to analyse the dynamics of the groundwater flow, a transient 3D groundwater flow model was developed for a subsurface dam. Methods applied to locate suitable sites for the construction of subsurface dams showed some promising results and need to be applied and tested in areas with different hydrological and geological conditions. The Boolean approach is a simple method that could be used during early planning stages for locating suitable sites for the construction of subsurface dams. The SMCA framework enabled the integration of knowledge for decision making, where the weights had a more significant influence on the results than the choice of the weighting method. AHP was considered to be the more robust model for assigning weights in this study. The factor removal technique showed that the modeling results were least sensitive to soil depth and most sensitive to land cover for the construction of subsurface dams. SRM showed reasonable results and could be used in engineering projects prior to detailed field investigations in formally glaciated terrain when borehole data is not available. The groundwater flow modelling results helped to develop some sustainable pumping scenarios to demonstrate the benefits of the subsurface dam. Groundwater flow model results also facilitated the selection of a suitable site for placing a subsurface dam in order to maximize the groundwater storage upstream. It was concluded in this project that the subsurface dams could sustainably be used to mitigate the water supply issues in formerly glaciated humid terrain such as in Sweden and dry climatic areas such as in Pakistan. Moreover, subsurface dams can play an important role in water resources management in coastal areas of formerly glaciated terrain, where saltwater intrusion is a rising environmental issue. Also in dry climatic areas like in Pakistan, methods such as SMCA could make the planning step more robust before the actual construction of dams. Themethods and findings presented in this thesis can be considered to be one tentative step of scientific contribution for better analysis, assessment and the location of subsurface dams. / <p>QC 20160210</p>

No description available.

Nickel-based super alloys are widely employed in the aerospace industry due to their high- temperature strength and high corrosion resistance. Because of the special application, the superficial residual stress of the super alloy is mandatory to 100% compressive stress according to the Federal Aviation Administration (FAA) regulations. In manufacturing of nickel-based super alloy components, grinding processes are necessarily applied as the final material removal step for achieving the stringent tolerance and surface finish requirements. During the traditional grinding process of Nickel based alloy, due to the thermal effect, tensile residual stress might be generated on the surface of the alloy. It's critical to transfer the tensile residual stress to compressive one which benefits on the fatigue life of alloy. In the thesis, a novel technology is developed to generate the superficial compressive residual stress with the method of embed a subsurface heating layer inside the workpiece to regulate the distribution of temperature field very before mechanical process. The residual stress might be reduced much, even transfer to compressive stress after combining the thermal effect. The numerical model will be built in the thesis including the induction model, heat transfer model, grinding heat model. Effects of different parameters on final subsurface heating layer will be studied including the coil parameters, concentrator parameters, coolant parameters, feed rate and also electromagnetic field properties such as the skin effect, proximity effect and slot effect. The thesis creates a system combining induction heating and cooling processes to regulate the temperature distribution in subsurface area that will be used for further stress analysis.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves [135]-139). Also available on the Internet.

There are 1,305 Superfund Sites on the United States Environmental Protection Agencies National Priorities List that may require remediation due to the environmental or human health risks associated with subsurface contamination. The contaminants present at these sites and others vary with respect to their physical and chemical properties which dictate the selection of appropriate remediation technologies. In-Situ Thermal Desorption (ISTD) has been studied as a remediation technique for removing many recalcitrant contaminants from soil. ISTD involves passing electrical current through heating elements in wells and removing contaminants through heater/vacuum wells. Heating occurs by heat conduction through the soil. At high temperatures, even relatively low volatility contaminants can be vaporized, removed by vacuum and treated with an on-site recovery system. The main objective of this research was to design and test a laboratory apparatus scaled to a typical ISTD field site and to use it to conduct experiments that could be used to aid in the validation of the STARS numerical simulator. A dimensional analysis was done on the governing energy balance equation to determine the most important scaling groups for the ISTD process so the laboratory experiments could be scaled up to the field. The laboratory apparatus was modeled after a symmetry element of the hexagonal field pattern and a triangular glass prism was constructed for heated sandpack experiments. Temperature data was measured in dry sand, sand partially saturated with water, and sand with both water and PCE added to it. The apparatus was made of glass so that the behavior of the PCE contaminant could be observed when the sand was heated. / text

We developed a prototype geophysical system that currently has a dynamic range of 126dB. We also calculate the full potential of our design to achieve a dynamic range of greater than 160dB, which is orders of magnitude higher than what is currently offered by state of the art technology in geophysical instrumentation. We have been successful in reducing measurement errors that are common limiting factors in achieving high measurement sensitivity in practice. We reduced the measurement error caused by mechanical deformations of the measurement apparatus from 70PPM to less than 1PPM. As a result of developing a novel measurement method for using a rotating antenna array and digital nulling, we achieved a level of temporal drift of less than 1PPM over a 50 minute time period, which is a significant improvement compared to the drift of greater than 100PPM for the state of the art geophysical instrumentation. We also used a method of simultaneous calibration of the secondary fields in order to correct the measured data for the long-term gain variations in the system response. As a result, we reduced the percentage error in the RE and IM components of the target response measured over a 105-minute period of time from 5% and 80% to 0.5% and 2%, respectively. We have gained a substantial reduction of the measurement errors caused by the background response of the earth by using the antenna array in a vertical orientation relative to the earth's surface. We demonstrated that our measurement method increases survey efficiency because of a more informative set of data. We tested our prototype system with a section of steel pipe, which is a standard target used to determine the sensitivity of commercial metal detectors. The measurement results showed that our current system will detect this particular target at a 2.0m depth below the earth's surface, which is 0.5m better than the 1.5m detection depth achieved by the EM61-MK2. When the full potential of our design is realized, we estimate the projected depth of detection to increase to 9m, which is six times greater than the detection depth achieved by the EM61-MK2.