Ongoing surface subsidence: how low can it go?

Extraction of fluids, like natural gas, from the Earth鈥檚 crust frequently results in surface subsidence and tremors, driven by reservoir compaction. This can be seen for example in the Groningen gas field, where the extraction of gas has a huge impact on the inhabitants living above the surface. Modelling the reversible, elastic component of compaction is straightforward. However, permanent deformation can also occur, the rate and effects of which are very poorly constrained. Therefore, the long-term surface impact of gas and fluid extraction cannot be predicted confidently.

Electron microscopy image of a gas bearing sandstone from the Groningen gas field. The gas is contained in the pores (black in the image). Each grain is covered with rims of clay that contribute to the total strength of the sandstone. Image: Bart Verberne

In this DeepNL research project the main mechanisms causing deformation of sands and sandstones under pressure, temperature and chemical conditions relevant to fluid extraction are quantified. Combining this with microscale theory and numerical modelling at the grain-scale will result in grain-scale deformation and interaction laws, that eventually will be upscaled to the field-scale. The project will provide a basis for strongly improving the predictive capability, needed for evaluating and mitigating long-term hazards related to fluid extraction. The knowledge that will be gained in this project is not just applicable to the Groningen gas field, but can also be used in the extraction of geothermal energy, groundwater pumping and CO2 injection.

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About DeepNL

The aim of the 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 giving 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.