REPROCESSING, DEPTH MIGRATION AND INTERPRETATION OF SEISMIC PROFILES IN THE NORTH-WESTERN MEDITERRANEAN SEA

The geological genesis, evolution and depositional settings of the Mediterranean Sea have been studied for decades by the scientific community which, for some aspects, combines research with the Petroleum Industry to enhance hydrocarbon exploration. It is in these circumstances that the geophysical study hereafter described was conceived. Two research bodies and a multi-client geophysical company have been involved in this project: the Department of Mathematics and Geosciences of the University of Trieste (DMG), the Italian National Institute of Oceanography and Experimental Geophysics (OGS) and TGS Geophysical Company ASA. The paper presents a geophysical analysis, based on interpretation of ten 2D multichannel seismic reflection profiles located in the Eastern Sardo-Provençal basin of the North-Western Mediterranean crossing domains from the outer West Sardinian shelf to the deep basin (Fig.1A,B). The post-stack time migrated lines have a total length of 1545 km and cover an area of about 35.000 km2. The profiles belong to three distinct datasets (WMR, WS, CROP, location on Fig.1A) recorded by different geophysical projects, each of them using specific acquisition parameters. The five WMR (West Mediterranean Regional) profiles were provided by TGS. The three WS (West Sardinia) profiles were acquired by their owner OGS. The two CROP (CROsta Profonda) lines, provided by the DMG, were originally sponsored by AGIP-ENI, CNR & ENEL. The presence of the Messinian rock salt, that within a sedimentary sequence produces halokinesis and scatters most of the acoustic energy, suggested the reprocessing in time domain of a part of a CROP seismic profile in order to improve the imaging of those reflections that are strongly deformed or masked. To enhance image accuracy assessing size and location of geological structures beneath the Messinian salt, a pre-stack depth migration (PSDM) was executed using the Kirchhoff algorithm. The processing outcomes were useful not only to enhance and better define the entire seismic interpretation on the available datasets, but also allowed the evaluation of the peculiar lithologic/stratigraphic conditions of the basin. The integration of the three datasets gave better coverage of the study area and supplied complementary information thanks to different resolutions. On the whole, the work presented hereafter aimed at better knowledge of the depositional history, starting from the Messinian Age, of the North-Western Mediterranean basin.