Postdoc position - Estimation of downhole RPM during drilling

Type de recrutement
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Détails (fichier)

Start date: Between now and January, 1st, 2023

Duration: 12 months

Salary: 2 780 euros before taxes

Joint position between Geosciences center and Systems and Control Center (CAS)

Context: Making geothermal energy harvesting cost-effective requires a drastic limitation of drilling costs, which are the main limitation for its large-scale development. Reducing costs entails limiting Non-Productive Time, failures and equipment damage, despite drilling at very low velocities into hard rock. A first step in this direction is to monitor the state of the drilling equipment, which can be challenging when only surface sensors are available.

The Systems and Control Center (CAS) has developed methods (a so-called ‘soft sensor’) to estimate downhole Rotations Per Minute (RPM) from topside sensors only, using distributed parameter models of the drilling dynamics and state-of-the-art observers for Partial Differential Equations. While this approach yields good results when drilling off-bottom, i.e. when the bit is not yet in contact with the rock, the complexity of the bit-rock interaction dynamics severely complicates the task when drilling on.

The Geosciences center has been developing bit-rock interaction mechanical models and validating them on experimental facilities for the past 20 years. The main objective of this project is to incorporate such models into the ‘soft sensor’ framework. This requires skills in physical modelling and model reduction, observer design, system identification. A good knowledge of the drilling process and / or of control of distributed parameter systems is a plus. The candidate will have access to databases of industrial data from both departments and their partners to evaluate the performances of the algorithms.

Contact: Florent Di Meglio (, Laurent Gerbaud (


  • U. J. F. Aarsnes, J. Auriol, F. Di Meglio, R. J. Shor, Estimating friction factors while drilling, Journal of Petroleum Science and Engineering, Volume: 179, pp. 80-91, 2019
  • Gerbaud, Laurent, Stephane Menand, and Hedi Sellami. "PDC bits: All comes from the cutter/rock interaction." IADC/SPE Drilling Conference. OnePetro, 2006.