Every year students from the Dutch “Foundation of Earth Science Career Day” aka SALD (Stichting Aardwetenschappelijke Loopbaandag) organize the Earth Science Career Event where several hundreds of geoscience students participate. The career day consists of various activities, including workshops, interactive debates and talks centred around the theme ‘Safety Through Innovation, the Future of Earth Science’.
At the job fair, many companies and research institutes were present, for instance Shell, TNO, Tata steel, EBN, Deltares, ESRI etc. The students also got the opportunity to meet and talk to PhDs to get a feeling for a scientific career. This is where Caspar Sinn and Wen Zhou presented their recent PhD work and answered questions about how the work and life of PhD students looks like in The Netherlands.
Wen presented his research to students who are interested in the induced seismicity in Groningen. The Groningen gas field in the Netherlands is one of the world’s largest onshore gas fields and has been producing since 1963. It was a fortune and pride for Dutch people. But as a result of gas extraction, subsidence and particularly induced seismicity occur since 1990s, causing damage and concern in the area. The dominant mechanism that triggers earthquakes in this Dutch gas field is reservoir compaction. Wen introduced how we can improve our knowledge of reservoir compaction by using just noise and deep borehole seismometers. Students were impressed how much useful information can be retrieved from background noise. There is potentially more work to do for further studies in order to fully understand induced seismicity in Groningen.
Caspar introduced students to the special behaviour of salt undergoing deformation. Though natural rocksalt is known to be practically impermeable, recent studies suggested that plastic deformation of fluid inclusions, and concomitant linkage, can lead to permeability increase in rocksalt. Caspar developed a simple microphysical model to assess the competition between passive stretching of inclusions by imposing stress and the shrinkage of inclusions due to surface-energy-driven, mass transfer (solution-precipitation). The model shows that mass transfer processes dominate in brine-filled inclusions, counteracting the stretching of the inclusions that could lead to the proposed development of a percolating network. This means, rocksalt undergoing natural deformation, is thought to remain impermeable and, thus, well suited to act as a geological barrier to seal over long durations.
Written by Caspar Sinn & Wen Zhou