Petro-physical Characterization of the Shallow Sediments in a Coastal Area in NE Italy from the Integration of Active Seismic and Resistivity Data

Abstract

Integrated geophysical analysis using different methods along with a priori information from wells, is a proven approach to investigate the geology and the petro-physical characteristics of subsoil. We collected seismic and geoelectric data in an area located on the Adriatic coast in North-Eastern Italy, aimed at characterizing the quaternary sediments and the shallow geological structures. Compressional and shear-wave data provided information about geometry and velocity of the quaternary sedimentary succession, while geoelectric data provided information about the resistivity in the shallower formation, which strongly depends on the presence of groundwater (brine) and on its salinity. Clustering analysis allowed us to subdivide the study area into subdomains showing similar values of resistivity and compressional- and shear-wave velocity, enabling for a better interpretation of the processed seismic sections. Then, we calculated the petro-physical properties of the investigated sediments, i.e., brine saturation and resistivity, porosity, and clay content, for each cluster. This inverse problem involves rock-physics theories and an optimization algorithm based on the simulated annealing global-search method. The results, validated using borehole stratigraphy, provided information about the salty water wedge intrusion.