Scientific context: The work proposed within this thesis is based on molecular simulations applied to oil industry. This latter often faces problems to predict the properties of a crude oil because such complex matrices are composed of hundreds of thousands or millions of different molecules, each one having its own physicochemical properties and reactivity. Metals under different forms can also be present, what renders the problem even more complex. In this way, understanding the dynamics and the reactivity of such individual and ensemble of molecules should allow one to elaborate new exploration strategies, from production to refining, adapted to each single crude oil based on its basic physicochemical properties. The molecular cartography strategy of such matrices is consisted of describing, in different scales, the physicochemical interactions playing a role on the observed properties, reactivity and dynamics. This is a compulsory step to understand, predict and control the physicochemical properties of these systems and is accomplished by following their properties and compositions from both analytical and theoretical chemistry.

Description of the research project: This project focuses on the identification of the asphaltene systems at the origin of the physicochemical properties and reactivity of oil residues. The successful candidate will develop new theoretical methods that should allow us to complete and deepen the knowledge already gained from the multi-scale and multi-technique approaches in place within our team and related to the research topics addressed by the C2MC laboratory https://c2mclab.wordpress.com/. To go beyond and answer concrete research topics of high interest for the industrial partners (TOTAL), Reactive Molecular Dynamics (R-MD) methods will be used or develop.

R-MD will allow one to (i) make a cartography of the asphaltene systems that have been recently studied in our group as well as mapping their vibrational properties and the signature characterising the interaction with their environment (calculation of infrared spectra from molecular dynamics trajectories)^1-4 ; (ii) to investigate their reactivity^5-8. The challenge of these studies clearly lays on the utilisation of well-adapted force fields for the R-MD method which must be parametrised in order to describe the system both around the equilibrium geometry, as classical forcefields, and at high energy close to the bond dissociation. This improved description of the chemical bonds under dynamic conditions, besides being able to describe temperature-dependant reactivity, also allows one to take into account anharmonic features of the potential energy surface needed to describe vibrational couplings that we are interested of.

Means: Software and HPC facilities needed for the execution of the project are available in our group and/or need to be programed.

Wanted profile: The successful candidate should hold a Master degree (Master 2 in France) or equivalent in Chemistry, Chemical-Physics, Physical-chemistry or Physics. S/he should be particularly motivated to work in an environment with national and international collaborations and also contact with industrial partners. English speaking, reading and writing skills are required. A previous experience in simulation and/or software development would be a plus.

How to candidate: please, send an updated CV and motivation letter to both [email protected] and [email protected]

Laboratory: Institut IPREM – Equipe ECP

website: http://iprem.univ-pau.fr/fr/index.html

Place: IPREM – Equipe ECP - Pau 

Starting date:  As soon as possible

Team:

Hugo Santos Silva (Post-Doctorant UPPA-TOTAL)

Germain Vallverdu (MCF institut IPREM – UPPA)

Didier Bégué (Pr institut IPREM – UPPA)

Isabelle Baraille (Pr institut IPREM – UPPA)

Bibliography:

1. On discerning intermolecular and intramolecular Vibrations in experimental acene spectra, F. Spillebout, D. Begue, I. Baraille, JM Shaw, Energy & Fuels, 28, 2933-2947 (2014)
2. Raman and photoacoustic infrared spectra of fluorene derivatives: Experiment and calculations, KH Michaelian, SA Oladepo, JM Shaw, X Liu, D. Begue, I. Baraille, Vibrational Spectroscopy, 74, 33-46 (2014)
3. Discerning Inter- and Intramolecular Vibrations of Sulfur Polyaromatic Compounds, P. Guevara Level, H. Santos-Silva, F. Spillebout, K. Michaelian, J. Shaw, I. Baraille, D. Bégué, soumis pour publication à J. Phys. Chem A
4. Adaptive vibrational configuration interaction (A-VCI): a posteriori error estimation to efficiently compute anharmonic IR spectra, R. Garnier, M. Odunlami, V. Le Bris, D. Bégué I. Baraille, O. Coulaud, J. Chem. Phys, 144, 204123 (2016)
5. Investigation of the Effect of Sulfur Heteroatom on Asphaltene Aggregation, A. C. R. Sodero, H. Santos Silva, B. Bouyssiere, J-P Korb, H. Carrier, A. Alfarra, D. Bégué, I. Baraille, Energy & Fuels, 30, 4758-4766 (2016)
6. Molecular Dynamics Study of Nanoaggregation in Asphaltene Mixtures: Effects of the N, O, and S Heteroatoms, H. Santos-Silva, A. C. R. Sodero, B. Bouyssière, H. Carrier, J-P Korb, A. Alfarra, G. Vallverdu, D. Bégué, I. Baraille, Energy & Fuels, 30, 5656-5664 (2016)
7. The role of metalloporphyrins on the physical-chemical properties of petroleum fluids, H. Santos-Silva, A. C. R. Sodero, J-P Korb, P. Giusti, A. Alfarra, G. Vallverdu, D. Bégué, I. Baraille, B. Bouyssière, Fuel, 188, 347-381 (2017)
8. Influence of molecular weight and lateral chain length on the physical- chemical properties of heavy oil

fractions: dependence on the scale, temperature and pressure, H. Santos Silva, A. Alfarra, G. Vallverdu, D. Bégué, B. Bouyssiere, I. Baraille, soumis pour publication à Fuel