Publications

The project objective was to detail better ways to assess and exploit intelligent oil and gas field information through improved modeling, sensor technology, and process control to increase ultimate recovery of domestic hydrocarbons. To meet this objective we investigated the use of permanent downhole sensors systems (Smart Wells) whose data is fed real-time into computational reservoir models that are integrated with optimized production control systems. The project utilized a three-pronged approach (1) a value of information analysis to address the economic advantages, (2) reservoir simulation modeling and control optimization to prove the capability, and (3) evaluation of new generation sensor packaging to survive the borehole environment for long periods of time. The Value of Information (VOI) decision tree method was developed and used to assess the economic advantage of using the proposed technology; the VOI demonstrated the increased subsurface resolution through additional sensor data. Our findings show that the VOI studies are a practical means of ascertaining the value associated with a technology, in this case application of sensors to production. The procedure acknowledges the uncertainty in predictions but nevertheless assigns monetary value to the predictions. The best aspect of the procedure is that it builds consensus within interdisciplinary teams The reservoir simulation and modeling aspect of the project was developed to show the capability of exploiting sensor information both for reservoir characterization and to optimize control of the production system. Our findings indicate history matching is improved as more information is added to the objective function, clearly indicating that sensor information can help in reducing the uncertainty associated with reservoir characterization. Additional findings and approaches used are described in detail within the report. The next generation sensors aspect of the project evaluated sensors and packaging survivability issues. Our findings indicate that packaging represents the most significant technical challenge associated with application of sensors in the downhole environment for long periods (5+ years) of time. These issues are described in detail within the report. The impact of successful reservoir monitoring programs and coincident improved reservoir management is measured by the production of additional oil and gas volumes from existing reservoirs, revitalization of nearly depleted reservoirs, possible re-establishment of already abandoned reservoirs, and improved economics for all cases. Smart Well monitoring provides the means to understand how a reservoir process is developing and to provide active reservoir management. At the same time it also provides data for developing high-fidelity simulation models. This work has been a joint effort with Sandia National Laboratories and UT-Austin's Bureau of Economic Geology, Department of Petroleum and Geosystems Engineering, and the Institute of Computational and Engineering Mathematics.

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As electronic assemblies become more compact and increase in processing bandwidth, escalating thermal energy has become more difficult to manage. The major limitation has been nonmetallic joining using poor thermal interface materials (TIM). The interfacial, versus bulk, thermal conductivity of an adhesive is the major loss mechanism and normally accounts for an order magnitude loss in conductivity per equivalent thickness. The next generation TIM requires a sophisticated understanding of material and surface sciences, heat transport at submicron scales, and the manufacturing processes used in packaging of microelectronics and other target applications. Only when this relationship between bond line manufacturing processes, structure, and contact resistance is well-understood on a fundamental level will it be possible to advance the development of miniaturized microsystems. This report examines using thermal and squeeze-flow modeling as approaches to formulate TIMs incorporating nanoscience concepts. Understanding the thermal behavior of bond lines allows focus on the interfacial contact region. In addition, careful study of the thermal transport across these interfaces provides greatly augmented heat transfer paths and allows the formulation of very high resistance interfaces for total thermal isolation of circuits. For example, this will allow the integration of systems that exhibit multiple operational temperatures, such as cryogenically cooled detectors.

As electronic assemblies become more compact and with increased processing bandwidth, the escalating thermal energy has become more difficult to manage. The major limitation has been nonmetallic joining using poor thermal interface materials (TIM). The interfacial, versus bulk, thermal conductivity of an adhesive is the major loss mechanism and normally accounts for an order magnitude loss in conductivity per equivalent thickness. The next generation TIM requires a sophisticated understanding of material and surface sciences, heat transport at sub-micron scales and the manufacturing processes used in packaging of microelectronics and other target applications. Only when this relationship between bondline manufacturing processes, structure and contact resistance is well understood on a fundamental level, would it be possible to advance the development of miniaturized microsystems. We give the status of the study of thermal transport across these interfaces.

Abstract not provided.

Abstract not provided.

The post-irradiation examination (PIE) of the NET-1.2 fuel element was completed in December, 1993. The goal of the PIE work was to gather data regarding the fracture of the hot frit during the experiment. Five cracks were observed in the hot frit at various locations although only two were believed to have initiated the overall component failure. These two cracks were complete circumferential failures and were located near the open and closed ends of the frit within the active flow region. The location and orientation of these fractures suggested that failure was the result of thermally-induced stresses that exceeded pre-test predictions. The cause of the failure was the temperature difference between the coolant flowing through the hot frit and the thermally massive end fittings. The resulting axial temperature gradients in the hot frit imposed thermal stresses that exceeded failure in the frit coating material. This coating fracture then propagated through the graphite substrate. Post-test analyses of the frit response based on measured data from the experiment verified that the frit coating failure stresses were exceeded. Additionally, the cold frit behaved unexpectedly. The PIE inspection of this component showed that a majority of the compliant panels were permanently deformed against the cold frit inner wall even though the transients that the bed was exposed to were not thought to be capable of creating this magnitude of bed expansion. No evidence of bed locking was observed. A calculational error in the prediction of the total bed expansion was found (post-PIE) which certainly contributed to the underestimation of the bed displacement. Additionally, temperature differences between the bulk of the frit and the panels created a bowing force which may have allowed some amount of bed settling at relatively low temperatures while particle thermal expansion was minimal.

Multi-dimensional radiative transfer in combined mode heat transfer problems was investigated with emphasis on the analysis and characterization of a free-falling particle cloud, direct absorption solar central receiver. A model was developed to calculate the relevant distributions in the curtain while a concentrated solar beam is impinging on the front face of the medium. The discrete ordinated approximation was applied to allow the spectral equation of transfer (EOT) to be modeled as a PDE. Model verification tests were conducted to determine the accuracy of the model. One- and two-dimensional results showed that the discrete ordinates model provides satisfactory estimates of the radiant intensity, the heat flux and the temperature distributions for ordinate sets above S{sub 4} (12-flux approximation) for both the black and gray cases. 75 refs., 69 figs., 13 tabs.