Modeling-Computer Simulations (Laney, 2005)

GEOTHERMAL ENERGY

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Exploration Activity: Modeling-Computer Simulations (Laney, 2005)

Exploration Activity Details
Location	Unspecified
Exploration Technique	Modeling-Computer Simulations
Activity Date
Usefulness	not indicated
DOE-funding	Unknown

 

Notes

Design of Sampling Strategies to Detect CO2 Emissions From Hidden Geothermal Systems, Lewicki, Oldenburg and Kennedy. The objective of this project is to investigate geothermal CO2 monitoring in the near surface as a tool to discover hidden geothermal reservoirs. A primary goal of this project is to develop an approach that places emphasis on cost and time-efficient near-surface exploration methods and yields results to guide and focus more cost-intensive geophysical measurements, installation of deep wells, and geochemical analyses of deep fluids. To this end, we present (1) the physical properties of CO2 key to its transport in the near-surface environment, (2) model simulations of geothermal CO2 migration and seepage that highlight fundamental features of these processes, (3) a discussion of the processes that affect natural background CO2 fluxes and concentrations within which anomalous geothermal CO2 must be discerned, (4) technologies that are currently available or will be potentially available in the future to monitor CO2 migration and seepage in the near surface, and (5) strategies based on integrated field measurements, numerical simulations, and statistical analyses to detect geothermal CO2 seepage fluxes and concentrations within the naturally varying background fluxes and concentrations. Technologies to monitor CO2 migration and seepage in the near surface: Available technologies for monitoring CO2 in the near-surface environment include (1) the infrared gas analyzer (IRGA) for measurement of concentrations at point locations, (2) the accumulation chamber (AC) method for measuring soil CO2 fluxes at point locations, (3) the eddy covariance (EC) method for measuring net CO2 flux over a given area, (4) hyperspectral imaging of vegetative stress resulting from elevated CO2 concentrations, and (5) light detection and ranging (LIDAR) that can measure CO2 concentrations over an integrated path. Technologies currently in developmental stages that have the potential to be used for CO2 monitoring include tunable lasers for long distance integrated concentration measurements and microelectronic mechanical systems (MEMS) that can make widespread point measurements. We assess each of these technologies in the context of measurement detection limit and error, spatial and temporal scale of measurement, availability, and cost of operation.

 

References

• Patrick Laney (2005) Federal Geothermal Research Program Update - Fiscal Year 2004