115 QUAL I TÉ GÉOPHYSIQUEAPPLIQUÉE 3 Borehole geophysical methods J.L. Mari Surface geophysical methods are stand-alone methods which enable the construction of a 2D or 3D geophysical model of the subsurface link to one or more physical parameters, such as resistivity for MT or EM methods, seismic wave velocities and density for seismic methods. Geological surveys associated with surface geophysical surveys lead to build a structural geological model to detect heterogeneities or tectonic features such fractures or faults. Such models are used to define the location of boreholes. Drilling of a borehole gives geophysicists the opportunity to perform borehole geophysical measurements and record additional data. Borehole geophysical methods give borehole measurements used to validate and calibrate geophysical models, to convert in depth geophysical models obtained in time (as example time migrated seismic sections in depth sections), to transform geophysical models in physical or petrophysical models. As example, seismic models in amplitude are converted into velocity models and then into porosity models. Borehole geophysical methods provide high-resolution, localized information on properties like lithology, porosity, and fluid content. Borehole geophysical methods can be classified as conventional logging methods, borehole surface imaging methods, hydrogeological logging methods, full © EDP Sciences, 2025 DOI: https://doi.org/10.1051/978-2-7598-3752-6.c003
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