GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 3.1 GNGTS 2024 Monitoring and No-Money-toring of Oil & Gas exploitaton in Italy T. Braun 1 , S. Danesi 2 1 Isttuto Nazionale di Geofsica e Vulcanologia, Sezione di Roma1, Arezzo, Italy 2 Isttuto Nazionale di Geofsica e Vulcanologia, Sezione di Bologna, Bologna, Italy The Val d'Agri basin (VA) is a Quaternary extensional basin bounded by two parallel and oppositely dipping normal fault systems. A M ∼ 7 earthquake that struck the VA in 1857 testfes the high seismic hazard of the region. The VA basin hosts the largest on-shore oil feld in on-shore Europe, producing hydrocarbon since the 1990s from a high-productve reservoir consistng of fractured, low-porosity Cretaceous limestones from producton wells drilled at 2 to 3 km depth below sea level (Butnelli et al., 2016). The ENI petroleum company is the main concessionaire in VA, operatng 25 productve wells located between the eastern side of the basin and the eastern ridge, and reaching producton rates around 90000 oil barrels/day. Since 2002, the operator installed a local seismic network to monitor the seismicity of the area and to study the potental infuence of industrial actvites on it. On 2014, the Italian Government decided to assign the monitoring dutes to an independent external consultant (Strutura Preposta al Monitoraggio, SPM, in Italian) and published experimental guidelines (ILG) (Dialuce et al., 2014) describing the recommendatons to be followed for the geophysical monitoring of hydrocarbon producton, waste-water injecton and gas storage. Only in the case of the injecton of incompressible fuids, the ILG propose the applicaton of a Trafc Light System that defnes a response scheme when seismic parameters exceed specifc thresholds. Parameters like Peak Ground Velocity (PGV), Peak Ground Acceleraton (PGA) and magnitude (ML) must be monitored when hypocentres are located within a defned spatal domain around the injecton well. (Braun et al., 2020). In 2017, the Italian Ministry for Economic Development commissioned INGV to act as monitoring agency (SPM) for the VA concession for exploitng hydrocarbons. In the standard operaton mode, the SPM is responsible for monitoring seismic parameters in near-real tme, and analysing them in conjuncton with ground deformaton (GPS and INSAR) and pore pressure fuctuatons on a biannual basis. The ILG defne the monitoring domains (Figure 1): an Extended (DE) and an Internal Domain (DI) based on the border of the Oil-Water contact of the reservoir, as well as a Reference Domain (DR), a cylindrical volume with a radius of 5 km along waste-water reinjecton well Costa Molina 2 (CM2). Important to note that the Trafc Light Protocol only applies to the DR (Braun and Danesi, 2022).