A Versatile Workflow for Building 3D Hydrogeological Models Combining Subsurface and Groundwater Flow Modelling: A Case Study from Southern Sardinia (Italy)

This research project aims to develop a basin-scaled 3D hydrogeological model by using Petrel E&P (Petrel 2021© ) as the basis for a numerical groundwater flow model developed with “ModelMuse”. A relevant aspect of the project is the use of Petrel 2021© geologic modelling tools in the field of applied hydrogeology to improve the details of both hydrogeological and numerical groundwater flow models, and their predictive capabilities. The study area is located in South Sardinia (Campidano Plain), where previous hydrogeological and modelling studies were available. The hydrogeological model was developed by digitising and interpreting the facies in the available borehole logs; a grid was subsequently created, including the main hydrogeological surfaces and performing geostatistical modelling of the facies based on grain size per-centages. Afterwards, an empiric formula, achieved from flow tests and laboratory analyses, was applied to the grain size distribution to obtain preliminary hydraulic conductivity values, calibrated during simulations. These simulations, under various groundwater head scenarios, established the boundary conditions and conductivity values needed to determine the hydrogeological balance of the study area. The probabilistic approach has produced a highly detailed model able to adequately represent the natural hydrogeological phenomena and the anthropic stresses in places underground.