Publication Date:
2015-04-30
Description:
ABSTRACT This work represents a case study concerning the application of reflection seismic imaging methods in the context of geothermal exploration. Our goal is to obtain accurate structural images of a geothermal active area in southern Tuscany. These images will be required in subsequent studies as the input for geological model building and numerical simulation of the heat transport and fluid flow. The target region exhibits great geologic complexity, including strong velocity contrasts, lateral near-surface inhomogeneities, fracture zones, and significant topography. Those features are typical for a volcanic hard-rock environment and pose significant challenges to conventional seismic imaging methodology. Therefore, we apply a sophisticated and robust depth imaging workflow to previously acquired surface seismic data. Within our workflow, we focus on estimating the seismic velocities of the predominant rock units and subsequently carry out Kirchhoff pre-stack depth migration and Fresnel volume migration to obtain high-resolution images of the subsurface. Our results demonstrate that the applied methodology provides a valueable tool for imaging in a complex environment such as a volcano-geothermal area. In detail, the resulting reflector images show the main horizons that delineate the Tuscan sedimentary rocks in the target region. The images from standard Kirchhoff migration can be significantly enhanced by utilizing Fresnel volume migration, which eliminates migration artefacts and provides a better result. Moreover, we obtain the migration velocities and depths for an important regional reflector, known as the K-horizon, which is of major interest for geothermal characterization.
Print ISSN:
0016-8025
Electronic ISSN:
1365-2478
Topics:
Geosciences
,
Physics
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