Summer school

A first reminder of the various geophysical techniques dedicated to the charcaterization of gas reservoir will be done. A specific focus on the seismic properties of a rock reservoir containing gas will then allow to manage a case study. The physical and chemical properties of the gas plume are used to interpret a seismic reflection survey and the definition of the gas plume envelop development versus time.

review of methodologies and techniques to monitore undergound storage sites and plants

This course introduces the basic principles required for the understanding of the hydrodynamic and geomechanical behavior of underground gas storage. First, we will present the fundamentals of multiphase flow with an emphasis on key processes to give a clear and rigorous understanding of the fundamental properties (capillary pressure, relative permeability), concepts and theory which are of importance in treating gas storage in subsurface. Then, we will discuss the various assumptions that simplify the complex reality to the extent that it can be described by rather simple and solvable models such the black oil formulation.

In a second step, we will present the basics of poromechanics. Poromechanics is the study of porous materials (rocks, soils…) whose mechanical behaviour is significantly influenced by the pore fluid. The focus is to give basic knowledge on the solid skeleton (elastic) behaviour and the solid/fluids coupling, by extending the fundamental concepts of continuum mechanics to continuum poromechanics. It is then relevant to reservoir geomechanics applications. This course includes introduction to both theory and laboratory experiments necessary for the determination of the parameters of constitutive laws.

Underground gas storage is a technological brick of the energy transition, whether it concerns energy carriers (natural gas, hydrogen) or CO₂. However, the realization of these projects often faces several challenges: 1) the viability of their economic model, 2) the state of the regulations in place, and 3) the reactions of stakeholders from the civil society, which question their legitimacy and their conditions of implementation. This course intends to explore these non-technical issues and discusses some avenues to address them.

This case study concerns an old abandoned career at Bicqueley, a little town, near from Nancy. This career allows to see and study Bajocian and Bathonian outcrops of two main sedimentary formations : the “Oolithe Miliaire Supérieure formation”, the reservoir facies constituted by hydraulic dunes of a porous oolithe limestone and the “caillasse à Anabacia”, the cap rock formation, a heterogeneous clay-limestone. Results of a geophysical survey will demonstrate how to manage the physical properties and geophysical responses of these two rock types, interpret and map their locations in the career. A fault is present in the zone and could be detected too using these geophysical techniques.

The goal of this course is to give the basis in geochemistry in order to better understand and constrain the chemical reactivity in fluid/rock systems. In particular, the emphasis will be given to aqueous solutions, gases and water-rock interactions. For aqueous solutions and water rock interactions, notions of ionic strength, activities of species in solution, saturation indexes, law of mass action, dissolution kinetics of minerals will be given.

One part of this course concerns the thermodynamic aspect of gas, mixture of gas and gas solubility in brine. First, we will present the different equation of state, their characteristic and the methods to determine their parameters, than we will present some experimental technique which can be used to measure their thermodynamic properties (mainly phase equilibria and density) and we will finish by the presentation of phase diagram in presence of water or brine.

ROSTOCK-H research partners in collaboration with Géodénergies will host a one-day workshop dedicated to geological storage of hydrogen. It will aim at discussing current technological status and research needs for the development of the underground hydrogen storage in salt caverns but also possible alternatives such as aquifers, depleted reservoirs or mined caverns. The main outcomes of the ROSTOCK-H project and experience from operating and planned facilities in the world will be presented.

The detailed program will soon be made available.

Access to the workshop is free, but registration is necessary

a) Geochemical and reactive-transport modelling

The goal is to apply your knowledge in geochemistry and hydrodynamic to model real systems.

The geochemical code, CHESS, and the reactive-transport code, HYTEC, developed at MINES ParisTech will be used to model gas-water, gas-water-salt and gas-water-salt-rock systems. Particular conditions of gas storage (i.e. high pressure) in saline formations (i.e. high salinity) will be considered. CHESS will help us accurately reproduce experimental solubility data from the literature, but also handle some reactivity problems (e.g. carbonation of cement materials within the frame of CO2 storage, or potential H2S generation within the frame of CH4 storage). Coupling of geochemistry and 2-phase flow and transport will finally be illustrated with CO2 injection simulations using HYTEC reactive-transport simulations.

b) Experimental and analytical approach for gas storage

This class will be focused on experimental and analytical approach used to better understand the behavior of a geological storage of CO2. An experiment will be performed on a limestone core-plug which will undergo the injection of a CO2-rich solution. The solubility of CO2 will be followed by in situ Raman spectrometry. The core plug after injection will be scanned by X-ray tomography in order to follow the dissolution network.

In parallel, an experiment dedicated to measure atmospheric gases by Infrared spectroscopy will be carried out to illustrate the geochemical monitoring aspects.