Internship | Estimating Net-to-Gross of Cenozoic Aquifers and Aquitards

The depth range of ~200 to ~1000m is under-explored in the Netherlands as it was historically ‘too deep’ for groundwater exploration, and ‘too shallow’ for O&G. Nowadays it is becoming more popular as target for shallow geothermal applications like HT-ATES and groundsource heatpumps, as well as LT-geothermal doublets. Because of its under-exploration lithological properties, like clay content, are poorly constrained it poses challenges regarding the geothermal potential and interaction with groundwater production. Data from which the clay content can be determined exists, but they are divers and therefore hard to combine into reliable maps on a national scale.

The clay-to-sand ratio, a.k.a. net-to-gross of a layer is important for both aquifers and aquitards. For an aquifer, it determines which part of a layer contributes to production and injection. For an aquitard, it determines to what extent the layer can be considered to prevent vertical flow. The national groundwater model REGIS-II is based on shallow drillings for which the lithology is described using the NEN5104, which has a definition for clay, sand, etc. There drillings rarely exceed a depth of ~200m. In deep drillings the lithology is rarely described in detail, but often gamma ray logs exist, which can be used to determine clay vs. sand, but using a different definition. A combination of deep and shallow data is challenging and hasn’t been tried yet.

Therefore the property characterization of the deeper REGIS aquifers and aquitards that are most interesting for geothermal is unreliable. No net-to-gross maps exist in REGIS. When a combination of a nearby deep and shallow drilling exists, or when a gamma ray log was obtained for a shallow drilling, both definitions of clay vs sand can be compared and uniformized. Once a common definition of net-to-gross is established, shallow and deep well information can be combined to interpolate a net-to-gross map for interesting layers such as in the Breda, Oosterhout and Maassluis Formations.

You will be working in the geohydrology team. In this team, about 10 geologists and hydrologists cooperate in projects aiming at a better parametrization of the intermediate depth subsurface between ~200 and ~1000m. Your work will be used as direct input for models that determine the national potential of geothermal, www.ThermoGIS.nl. The team is part of the research group Hydrology and Reservoir Engineering.

We expect that the candidate is able to work independently, and cooperate with colleagues from different background (geology, geo-hydrology, geophysics etc),. with different data types (shallow wells, core samples, deep wells, seismic data). The candidate should have good knowledge of the Dutch subsurface and of the sedimentary processes leading to the deposition of sandy and clayey layers present. A bachelor in Earth Sciences or a related topic is expected. Some knowledge of programming tools (Python) and modeling / GIS software (QGIS, Petrel) is a pre.

You want an internship opportunity on the precursor of your career; an internship gives you an opportunity to take a good look at your prospective future employer. TNO goes a step further. It’s not just looking that interests us; you and your knowledge are essential to our innovation. That’s why we attach a great deal of value to your personal and professional development. You will, of course, be properly supervised during your work placement and be given the scope for you to get the best out of yourself. Furthermore, we provide:

• A highly professional, innovative internship environment, within a team of top experts.
• A suitable internship allowance (615 euro for wo-, hbo- and mbo-students, for a full-time internship).
• Possibility of eight hours of free leave per internship month (for a full-time internship).
• A free membership of Jong TNO, where you can meet other TNO professionals and join several activities, such as sports activities, (work-related) courses or the yearly ski-trip.
• Use of a laptop.
• An allowance for travel expenses in case you don’t receive an OV-card.

At TNO, we innovate for a healthier, safer and more sustainable life. And for a strong economy. Since 1932, we have been making knowledge and technology available for the common good. We find each other in wonder and ingenuity. We are driven to push boundaries. There is all the space and support for your talent and ambition. You work with people who will challenge you: who inspire you and want to learn from you. Our state-of-the-art facilities are there to realize your vision. What you do at TNO matters: impact makes the difference. Because with every innovation you contribute to tomorrow’s world. Read more about TNO as an employer.

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After the first CV selection, the application process will be conducted by the concerning department. TNO will provide a suitable internship agreement. If you have any questions about this vacancy, you can contact the contact person mentioned below.

Important to be aware of before applying:

• Before the start of the internship, the internship agreement from TNO needs to be signed. For students at a college or university based in the Netherlands, TNO uses the UNL-template (supplemented with a number of specific agreements from TNO). For students of foreign and MBO educational institutions, the TNO internship agreement applies. TNO does not sign any other internship agreements.
• Before the start of the internship, the educational institution will need to confirm in writing that:
  • 1) you are enrolled at the educational institution during the internship, and;
  • 2) the internship takes place as part of the programme of the study.
• The confirmation of educational institution takes place by signing the UNL template or forms prepared by TNO.
• Interns at TNO must be in possession of a Dutch residential address at the start of the internship. Performance of internship activities from abroad is not possible.