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Development of a HT seismic downhole tool

Chavira, David C.; Henfling, Joseph A.; Greving, Jeffrey J.

Enhanced Geothermal Systems (EGS) require the stimulation of the drilled well, likely through hydraulic fracturing. Whether fracturing of the rock occurs by shear destabilization of natural fractures or by extensional failure of weaker zones, control of the fracture process will be required to create the flow paths necessary for effective heat mining. As such, microseismic monitoring provides one method for real-time mapping of the fractures created during the hydraulic fracturing process. This monitoring is necessary to help assess stimulation effectiveness and provide the information necessary to properly create the reservoir. In addition, reservoir monitoring of the microseismic activity can provide information on reservoir performance and evolution over time. To our knowledge, no seismic tool exists that will operate above 125 C for the long monitoring durations that may be necessary. Replacing failed tools is costly and introduces potential errors such as depth variance, etc. Sandia has designed a high temperature seismic tool for long-term deployment in geothermal applications. It is capable of detecting microseismic events and operating continuously at temperatures up to 240 C. This project includes the design and fabrication of two High Temperature (HT) seismic tools that will have the capability to operate in both temporary and long-term monitoring modes. To ensure the developed tool meets industry requirements for high sampling rates (>2ksps) and high resolution (24-bit Analog-to-Digital Converter) two electronic designs will be implemented. One electronic design will utilize newly developed 200 C electronic components. The other design will use qualified Silicon-on-Insulator (SOI) devices and will have a continuous operating temperature of 240 C.

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TYPE Conference YEAR 2009
OSTI

A total risk assessment methodology for security assessment

Wyss, Gregory D.; Otero, Consuelo J.; Pless, Daniel; Rhea, Ronald E.; Kaplan, Paul G.

Sandia National Laboratories performed a two-year Laboratory Directed Research and Development project to develop a new collaborative risk assessment method to enable decision makers to fully consider the interrelationships between threat, vulnerability, and consequence. A five-step Total Risk Assessment Methodology was developed to enable interdisciplinary collaborative risk assessment by experts from these disciplines. The objective of this process is promote effective risk management by enabling analysts to identify scenarios that are simultaneously achievable by an adversary, desirable to the adversary, and of concern to the system owner or to society. The basic steps are risk identification, collaborative scenario refinement and evaluation, scenario cohort identification and risk ranking, threat chain mitigation analysis, and residual risk assessment. The method is highly iterative, especially with regard to scenario refinement and evaluation. The Total Risk Assessment Methodology includes objective consideration of relative attack likelihood instead of subjective expert judgment. The 'probability of attack' is not computed, but the relative likelihood for each scenario is assessed through identifying and analyzing scenario cohort groups, which are groups of scenarios with comparable qualities to the scenario being analyzed at both this and other targets. Scenarios for the target under consideration and other targets are placed into cohort groups under an established ranking process that reflects the following three factors: known targeting, achievable consequences, and the resources required for an adversary to have a high likelihood of success. The development of these target cohort groups implements, mathematically, the idea that adversaries are actively choosing among possible attack scenarios and avoiding scenarios that would be significantly suboptimal to their objectives. An adversary who can choose among only a few comparable targets and scenarios (a small comparable target cohort group) is more likely to choose to attack the specific target under analysis because he perceives it to be a relatively unique attack opportunity. The opposite is also true. Thus, total risk is related to the number of targets that exist in each scenario cohort group. This paper describes the Total Risk Assessment Methodology and illustrates it through an example.

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TYPE Conference YEAR 2009
OSTI

High-g shock test results of Tadiran TLM-1530MP cells

O'Malley, Patrick D.

In April of 2009, testing was done of a high-g instrumentation device that utilized Tadiran TLM-1530MP cells as a power source. As a result of that testing, it was determined that those cells exhibit failure more often when shocked in the axial direction. No failures over many tests where found when the cells were shocked laterally. Moreover, when shocked laterally, the cells exhibited no observable degradation in performance. We looked at the failed cells via non-destructive x-ray analysis to determine what internal structures failed.

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TYPE SAND Report YEAR 2009
DOIOSTI
Results 75301–75325 of 99,299
Results 75301–75325 of 99,299