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This paper deals with the design, acquisition and processing of vertical seismic profiling data collected in 2016 at the directional Thônex‐01 geothermal well, drilled in 1993 in the Geneva Canton (Switzerland). The aim of the study was to obtain additional information from existing‐abandoned well for downhole geophysical characterization of potential geothermal reservoirs in the Geneva area. The main results obtained by this study allowed an improved subsurface image by multi‐offset acquisitions near and around the deviated well. Specifically we were able to (1) improve the velocity model of the Geneva Basin, which, at present, is only constrained by one unique deep exploration well, located at the south‐west of the basin, far away from the study area; (2) image the transition between the Tertiary Molasse siliciclastic sediments and the Mesozoic carbonates; (3) define an acquisition strategy for future vertical seismic profiling surveys in support of the geothermal exploration campaigns in the area. This study has demonstrated the value of vertical seismic profiling method for the refinement of the subsurface geology at local scale, and its usefulness to assist the planning of second well associated with geothermal doublets. [ABSTRACT FROM AUTHOR]

We examine the multidimensional deconvolution (MDD) approach for virtual-reflector (VR) signal representation by cross-convolution. Assuming wavefield separation at receivers, the VR signal can be synthesized by cross-convolution of inward and outward wavefields generated from a multiplicity of transient sources. Under suitable conditions, this virtual signal is representable as the multidimensional composition of (1) the outward wavefield from the redatumed virtual sources at receivers and (2) of the so-called point-spread function (PSF) for VRs. Multidimensional inversion of the PSF provides the solution to get deblurred signals and recover the Green's function either of transmitted wavefields or reflectivity. This approach is similar to the MDD by backward seismic interferometry of cross-correlation type. The forward approach by cross-convolution poses the issue to use suitable projections and representations by functions with convex trends in space and time. This work discusses the main differences for illumination and stability in the cross-convolution and cross-correlation approaches, providing, under appropriate coverage conditions, equivalent and robust inversion results. [ABSTRACT FROM PUBLISHER]