Assessment of seismicity and risk from gas injection in the Groningen gas field

Abstract. Production of natural gas from the Groningen gas field in the Netherlands has led to earthquakes, the societal impact of which has ultimately led to the decision to cease all gas production from the field starting October 2023. Seismicity is expected to continue for some time, even after production has stopped, at least in part because of the existing pressure gradients in the field and the time that it will take for gas to re-distribute and pressure to equilibrate. We investigate the possibility to reduce the seismicity by means of gas injection. We employ a dedicated model chain previously developed to model gas production, induced seismicity, and associated hazard and risk. The model chain was adapted to support modelling of pressure increases associated with gas injection, and to account for the effects of reservoir cooling when relatively cold gas is injected. Several injection scenarios are considered that are based on realistically feasible total injection gas volumes. Additional scenarios are designed to provide useful insight into fundamental mechanisms. The scenarios are compared to a no-injection reference case to be able to identify and quantify beneficial effects. The results indicate that reductions in seismicity can be achieved in all scenarios and that these reductions could be substantial also for relatively modest volumes of injection gas. The results also show that benefits may be lost if injection is stopped before reservoir-wide equilibration has been achieved. We discuss also some limitations of the model chain and highlight possibilities to deploy more targeted injection schemes.