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| Titel |
Optimal experimental design for placement of boreholes |
| VerfasserIn |
Kateryna Padalkina, H. Martin Bücker, Ralf Seidler, Volker Rath, Gabriele Marquart, Jan Niederau, Michael Herty |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250096049
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| Publikation (Nr.) |
 EGU/EGU2014-11532.pdf |
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| Zusammenfassung |
| Drilling for deep resources is an expensive endeavor. Among the many problems finding the
optimal drilling location for boreholes is one of the challenging questions. We contribute to
this discussion by using a simulation based assessment of possible future borehole locations.
We study the problem of finding a new borehole location in a given geothermal reservoir in
terms of a numerical optimization problem.
In a geothermal reservoir the temporal and spatial distribution of temperature and
hydraulic pressure may be simulated using the coupled differential equations for heat
transport and mass and momentum conservation for Darcy flow. Within this model the
permeability and thermal conductivity are dependent on the geological layers present in the
subsurface model of the reservoir. In general, those values involve some uncertainty making it
difficult to predict actual heat source in the ground. Within optimal experimental the question
is now at which location and to which depth to drill the borehole in order to estimate
conductivity and permeability with minimal uncertainty. We introduce a measure for
computing the uncertainty based on simulations of the coupled differential equations. The
measure is based on the Fisher information matrix of temperature data obtained through
the simulations. We assume that the temperature data is available within the full
borehole. A minimization of the measure representing the uncertainty in the unknown
permeability and conductivity parameters is performed to determine the optimal borehole
location.
We present the theoretical framework as well as numerical results for several 2d
subsurface models including up to six geological layers. Also, the effect of unknown layers
on the introduced measure is studied. Finally, to obtain a more realistic estimate of optimal
borehole locations, we couple the optimization to a cost model for deep drilling
problems. |
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