Comprehensive monitoring and prediction of seismicity within the Groningen gas field using large scale field observations
It is well known that the seismicity in the Groningen area is due to gas extraction. The dynamics of how the site and rate of extraction is related to the magnitude and frequency of seismicity, however, is not understood. In a synergetic collaboration between the Department of Applied Mathematics at the University of Twente and the Department of Earth Sciences at Utrecht University, we propose to develop state-of-the-art tools to comprehensively address this extraction-seismicity causality.
We will use existing 3D velocity models of the subsurface to calculate Green’s functions by randomly changing seismic sources, geometry, stress and elastic structure. In a time-lapse setting, these Green’s functions will be used to train neural networks, which will monitor the changes of the parameters of interest fast and in a fully probabilistic setting. Full waveform inversion and the generation of Green’s functions is computationally very expensive. We will therefore develop a reduced order model within the 3D wave propagation solver. Finally we will develop, based on stochastic geometry, a prediction tool for seismicity using gas production and these monitoring data as input.
The monitoring tools we propose to develop will produce data, which are essential for any geomechanical modelling in the area. Of special interest is the near sub-surface. We will produce response functions essential for structural engineering work. The prediction tool will be of crucial importance for decision makers who set future gas extraction policies. All our tools and data will be openly available.
Our project is part of a larger NWO programme. The aim of this DeepNL research programme is to improve the fundamental understanding of the dynamics of the deep subsurface under the influence of human interventions.
With DeepNL, NWO is providing a concrete response to the advice of the Dutch Safety Board: ensure that there is a structural and long-term research programme into the gas-extraction related problems in Groningen. This NWO research programme has been made possible in part by a financial contribution from NAM. DeepNL will be realised in accordance with the usual NWO procedures and quality standards and is entirely independent. NAM is not involved in the decision-making or the specific management of the programme. DeepNL is part of NWO’s contribution to the Top Sector Energy.