The near injection borehole reservoir rock is a highly important volume of material which partly controls the success of geothermal projects. It controls how easy it is to re-inject geothermal brines, which is one of the major operational issues which affects geothermal projects. This rock can be damaged during drilling, will have the highest flowrates, and the largest thermal gradients in the geothermal system. It is noted that geo-chemistry and micro-biology are also important in this topic, but have been excluded due to time. The thermo-hydro-mechanical behaviour may cause an increase or reduction in overall permeability, by shrinkage which reduces pore space or micro-cracking which can increase permeability.

A research geothermal well, being developed on the TU Delft campus (DAPwell), will have a novel fibre optic sensing system for acoustic emissions in the injector well. Cemented tightly to the formation, optical fibres will be able to detect acoustic emissions from micro-cracking events. These events will be due to (i) the modified in-situ stress field due to drilling; (ii) the thermally induced volume changes in the rock (shrinkage mainly in the injection well); (iii) changes in the strength properties of the rock due to flow erosion or geo-chemical activity. In addition, the DAPwell research programme will collect downhole logs both initially and at various times during operation.

Bringing together numerical modelling of the thermo-hydro-mechanical behaviour and detailed observations from the DAPwell will result in new insights into the occurring behaviour, and the ability to further test operational techniques to best improve or maintain permeability. This will have the consequence of being able to maintain pumping pressures and rates (normally the pressure increases and/or the rate decreases) which (a) increases production efficiency and durability, and (b) reduces the seismic risk.

This work will benefit from other projects taking place as part of the DAPwell research programme, for example thermo-hydro-mechanical testing of reservoir rocks and micro-structural scanning of reservoir cores.

The objectives of this position are:

• Develop an understanding of the thermo-hydro-mechanical processes around the injection wells of geothermal systems. Focus will be on processes which impact the injectibility and/or stability.
• Develop concepts of how the thermo-hydro-mechanical processes could be utilised to benefit both safety (reduce seismic risk) and efficiency and durability (improve injectibility).

Proposed activities:

• Develop a thermo-hydro-mechanical model for the near borehole processes around the injection well, including reservoir rock failure processes. It is anticipated that thermally induced mechanics.
• Analyse acoustic emission data collected from the DAPwell to identify location and magnitude of cracking events.
• Couple the model results with collected acoustic emissions, injection data and borehole logs to improve modelling and validate simulated behaviour.
• Numerically investigate different operational methods (different injection temperatures and pressures) to control downhole behaviour.

The student will be able to take advantage of the EASYGO project consortium. The student is proposed to have secodments to RWTH Aachen (Prof Florian Wellmann/Florian Amann) and to the geothermal developer and operator Hydreco Geomec (Barbara Cox). Four training weeks will be organised during the EASYGO project where various aspects of geothermal energy and research skills will be presented.

We are looking for an excellent candidate with the following qualifications, knowledge and skills:

• A master degree in applied earth science, civil engineering, geophyscis, mechanical engineering or another degree with a substantial mechanics, fluid flow and/or geophysics content.
• Knowledge of computational modelling (of mechanics) and geophysics interpretation would be an asset.
• Insight into comparing experimentally collected data and numerical models, with a consideration of uncertainties would be a benefit.
• Excellent written and oral communication skills in English are required.

If your mother language is not English and you do not hold a degree from an institution in which English is the language of instruction, you must submit proof of English proficiency from either TOEFL (minimum total score of 100) or IELTS (minimum total score of 7.0). Proof of English language proficiency certificates older than two years are not accepted.

Fixed-term contract: 4 years.

TU Delft offers PhD-candidates a 4-year contract, with an official go/no go progress assessment after one year. Salary and benefits are in accordance with the Collective Labour Agreement for Dutch Universities, increasing from € 2395 per month in the first year to € 3061 in the fourth year. As a PhD candidate you will be enrolled in the TU Delft Graduate School. The TU Delft Graduate School provides an inspiring research environment with an excellent team of supervisors, academic staff and a mentor. The Doctoral Education Programme is aimed at developing your transferable, discipline-related and research skills.

The TU Delft offers a customisable compensation package, discounts on health insurance and sport memberships, and a monthly work costs contribution. Flexible work schedules can be arranged. For international applicants we offer the Coming to Delft Service and Partner Career Advice to assist you with your relocation.

During the first three years, the salary will be covered via the Marie Curie Project allowances.

Delft University of Technology

Delft University of Technology is built on strong foundations. As creators of the world-famous Dutch waterworks and pioneers in biotech, TU Delft is a top international university combining science, engineering and design. It delivers world class results in education, research and innovation to address challenges in the areas of energy, climate, mobility, health and digital society. For generations, our engineers have proven to be entrepreneurial problem-solvers, both in business and in a social context. At TU Delft we embrace diversity and aim to be as inclusive as possible (see our Code of Conduct). Together, we imagine, invent and create solutions using technology to have a positive impact on a global scale.

Challenge. Change. Impact! 

Faculty Civil Engineering & Geosciences

The Faculty of Civil Engineering & Geosciences (CEG) is committed to outstanding international research and education in the field of civil engineering, applied earth sciences, traffic and transport, water technology, and delta technology. Our research feeds into our educational programmes and covers societal challenges such as climate change, energy transition, resource depletion, urbanisation and the availability of clean water, conducted  in close cooperation with a wide range of research institutions. CEG is convinced that Open Science helps to achieve our goals and supports its scientists in integrating Open Science in their research practice. The Faculty of CEG comprises 28 research groups in the following seven departments: Materials Mechanics Management & Design, Engineering Structures, Geoscience and Engineering, Geoscience and Remote Sensing, Transport & Planning, Hydraulic Engineering and Water Management.

Click here to go to the website of the Faculty of Civil Engineering & Geosciences.

Department
The PhD student will be hosted at the Geo-Engineering Section in TU Delft, but will also work in close cooperation of the Applied Geophysics Section. The supervision committee at TU Delft will be made up of Associate Professor Phil Vardon, Associate Professor Guy Drijkoningen and Assistant Professor Anne-Catherine Dieudonné, and at RWTH Aachen Professor Florian Wellmann/Professor Florian Amann.

The Department of Geoscience and Engineering conducts a programme for inventive exploration, exploitation and use of the Earth’s resources and subsurface space. It employs ca. 150 staff members (including PhD students) and teaches ca. 300 BSc and MSc students. It has an internationally leading role in research related to Applied Geophysics and Petrophysics, Petroleum Engineering, Applied Geology, and Geoengineering. It owns a new, sophisticated laboratory where processes are observed and measured under in-situ conditions.  

The Geo-Engineering Section is internationally oriented, with many staff members and students from outside the Netherlands, and a large number of international research and educational contacts. The Section of Geo-Engineering has 9 full-time and 5 part-time academic staff, and 25 PhD and post-doctoral researchers. Areas of expertise include geo-mechanics, dykes and embankments, foundation engineering, underground space technology, engineering geology, and geo-environmental engineering.

Across the department, geothermal engineering has become one of the focal points for developments in the last few years, taking advantage of the changes in the energy provision in the Netherlands and of the plans to drill a deep geothermal research-well doublet on campus. A “geothermal theme” has been established as a platform cross-cutting all sections within the department. The section combines an extensive programme of laboratory research with numerical simulation and in-depth mathematical analysis.