2024 Program

​The presentation by our colleagues from Terrensis highlighted the prospective interest in natural hydrogen in this specific area of the French Pyrenees. The aim of this new intervention will be to show that, in addition to its promising geological position, the "Grand Rieu" project, led by 45-8 Energy and Storengy, and more generally the projects in the area, are in a very favorable “Above Ground” situation.  The location encourage synergies between projects, at upstream and downstream levels as part of a particularly dynamic local and regional hydrogen ecosystem, supported by existing infrastructures or infrastructures already in project. It will facilitate concrete offtake opportunities for natural hydrogen and any associated co-products. We will also look at the production volumes that could be envisaged, the estimated production costs to date and the current timeline in order to fully materialize this promising project for the natural hydrogen industry in France and Europe.​

The Armorican Massif, Breton peninsula, is located in the far west of France. It consists of Proterozoic and Paleozoic sedimentary, magmatic and metamorphic formations that were deformed by the Cadomian and Variscan orogenies. It extends to the east under the Mesozoic and Cenozoic sedimentary series of the west of the Paris basin of which it constitutes the bedrock. Although lacking obvious targets (e.g. large mantle rock bodies), the variety of rocks that make up the Armorican basement and its high-density fault network of various age are worth exploring for the formation of hydrogen and its migration. The geochemical surveys we have carried out over the last two years highlighted hydrogen anomalies in soils. In the Brittany region, we will study the possible accumulation in the fractured basement. Further east, in the Paris Basin, hydrogen could have been trapped in the Mesozoic sedimentary reservoir formations (Lefeuvre et al., 2024).

Co-auteur : Christophe Rigollet, Vincent Roche, Nicolas Lefeuvre, Yannick Branquet, Eric Thomas, Jeanne Bride, Ulysse Froger

The research consortium associated with the REGALOR project (REssources GAzières de LORraine - FEDER/French State and Grand Est Region, 2018-2023) after having demonstrated the existence of natural hydrogen resources in the Lorraine carboniferous basin, has for the first time, specified the location of these resources within different geological formations. On the basis of SysMoGTM type probe technology (European Bureau Patent N°EP22210240.2 April 2023), the concentrations of dissolved gases (CO2, H2, CH4 and N2) and their isotopic signatures could be determined both in the Carboniferous sediments trough a vertical well (FOLS1A - Folschviller-France), between -600m and -1250m and directly in the coal seams abg trough 3 deviated flooded wells, at -925m (Well A), at -930m (Well B) and at -946 m (Well C).
In the Carboniferous sediments (vertical well FOLS1A), the concentrations at -1250 m in H2, CH4, N2 and CO2 are respectively 18.2, 7.4, 6.5, <0.05 mole%. On the contrary, measurements directly in the coal seams showed a very different relative proportion of these three gases, namely between 0.05 and 0.5 mole % for H2, between 87.0 and 96.0 mole % for CH4 , between 2.9 and 11.8 for N2 and between 0 .03 and 0.6 mole% for CO2. A high CH4 content (96 mole%) associated with a very low hydrogen content (<0.05%) in the coal veins, confirm the different origins for CH4 and H2. Moreover, the d13C-CH4 and Deuterium d2H-CH4 isotope data are similar for the FOLS1A, wells B and C. They vary between -43.8 and 39.9 ‰ for d13C-CH4 and between -238 and -208 ‰ for d2H-CH4. This shows that the methane contained in the coal seams and in the Carboniferous sediments are identical, thus reflecting a diffusion of CH4 from the coal seams (place of genesis) to the surrounding geological environment (additional storage zone). On the other hand, the absence of hydrogen in the tested coal veins can be limited by the following three hypotheses:
- a relative impermeability of coal deposits to hydrogen,
- a process of bio-physicochemical degradation within the veins,
- a mechanism of adsorption of H2 on the coal. In this case the concentration measured in the vein would be the equilibrium concentration of this process.
Because of the small hydrogen concentrations in the tested coal seams, isotopic analysis of H2 (for d2H-H2) could not be carried out. Nitrogen isotopia is inconclusive. The value of d15N is constant in the different boreholes studied at +1.5‰. It is located in the average of the d15N values described for global coals with reference to the publication by Quan and Adeboye (2021).
This research demonstrates that in a carboniferous context, the search for dissolved H2 must also be carried out outside of the coal seams, by targeting the surrounding submerged sediments, using exploration tools of SysMoGTM type. These results confirm the hypothesis of a production of H2 in deep conditions (>5 km), possibly from water-rock interaction, and the extremely low permeability of coal seams.

Philippe de DONATO1, Jacques PIRONON1, Raymond MICHELS1, Odile BARRES1,
Marie-Camille CAUMON1, Aurélien RANDI1, Catherine LORGEOUX1, Yves
GERAUD1, , Mathieu LAZERGES1, Vitaliy PRIVALOV1,5, Antoine FORCINAL2,
Fady NASSIF2, Médéric PIEDEVACHE3, Thomas FIERZ4, Yanick LETTRY4,
1Université
de Lorraine, CNRS, GeoRessources lab, F-54500 Vandœuvre-lès-Nancy,
France 2LFDE, Avenue du district – ZI Faulquemont, F-57380 Pontpierre,
France
3Solexperts France, 10, allée de la forêt de la Reine, F-54500
Vandœuvre-lès-Nancy, France 4Solexperts AG, Mettlenbachstrasse 25,
CH-8617 Mönchaltorf, Switzerland
5National Academy of Sciences of Ukraine, UA-03142 Kyiv, Ukraine

Co-authors; Daniel Palmowski, Adrian Kleine, Thomas Hantschel

Terranta GmbH, Aachen, Germamy

Exploration activity for natural hydrogen has grown significantly in recent years. The geologic concepts and processes required for natural hydron to produce economic hydrogen accumulations are being more and more refined to support the efforts to explore for geologic hydrogen resources. The hydrogen system concept, adopted from the petroleum system approach, is now being applied for many exploration projects around the world. New and effective tools to model the hydrogen system are being developed. Adopting some of the workflows form hydrocarbon and combining them with those of mineral exploration, two- and three-dimensional reactive transport modeling offers an effective approach to test our hypothesis and concepts for consistency and efficiency. The modeling of hydrogen generation, migration and accumulation requires however several new modeling technologies and as well as a better understanding of how the generated hydrogen migrates through the subsurface.

Any “working” hydrogen system requires efficient hydrogen expulsion from a source rock. Generation via serpentinization or radiolysis can only lead to efficient hydrogen expulsion if the generated hydrogen is transported out of the source rock to prevent a thermodynamic equilibrium situation within the source rock. Therefore, the key to modeling hydrogen systems is describing and quantifying the flow of water in the subsurface. Water accessibility is critical for the generation processes (serpentinization or radiolysis), the water-flow rate is critical to understand the transport of hydrogen and hence the effective expulsion from the source rocks.

An extension to the simple Darcy flow formulation of the water flow is required to address the complexity of flow drivers (density driven flow/convection) and the complexity of hydrogen transportation and migration (advective and diffusive transport, free-phase flow). To solve such problems using numerical methods requires smart and efficient grids, to not only deliver the numerical base for solving complex differential equations. The grids need to be capable of representing the needed geometric complexity of the geological models. Additionally, the modeling of convection and advective transport adds new and different scales, in both space and time, to the model.

We will present and illustrate the status quo of Hydrogen Systems Modeling based on real case studies. Modeling the flow rates of water in the subsurface on the needed scales and accuracies the combination with reactive flow modeling capabilities opens the capabilities to quantitatively assess hydrogen systems to de-risk exploration projects.

Exploration of natural hydrogen in various geological contexts (ophiolites, cratons, superficial macro-seeps and subsurface accumulations discovered through drilling) gives today a decent geochemical database on gas concentrations (hydrogen, nitrogen methane, helium and other noble gases), as well as isotopic ratios (Hydrogen, carbon, nitrogen, noble gas isotopes).
Several fundamental questions related to natural hydrogen are still under discussion:
- Is a hydrogen system a renewable system at human time scale?
- Why nitrogen and helium are always associated with hydrogen in various proportions, whereas their generation is generally not related to the hydrogen generation as understood today?
- How to quantify the interest of a hydrogen system, in terms of future production?
- While hydrogen fields will be produced, will the gas composition remain constant through time, or could occur a shift of gas composition versus the amount of produced gas?
Fossil noble gas isotopes (20Ne, 36Ar, 84Kr for example) are present in the Earth atmosphere, and in aquifers equilibrated with the air concentrations (ASW). They represent very simple geochemical natural tracers in gas phases, as their sources are very well characterized, as well as their physical properties. As they are chemically inert, any observed fractionation needs to be related to physical processes as phase exchanges (in our case, only water and vapor phases), diffusion and adsorption/desorption on solid surfaces. Radiogenic noble gas isotopes as 4He and 40Ar, which amounts are increasing with time, present chronometers associated with the geological fluids.
Fossil isotopes, measured in various geological occurrences of natural hydrogen, present a good consistency, and indicate clearly that they suffered large physical fractionations, which cannot be related to any simple mixing process between geological reservoirs. Their behavior is very different than when associated with hydrocarbon accumulations. We demonstrate that they suffered a fractionation linked to their extraction from aquifer water and desorption from solid surfaces into a gas phase (hydrogen blend gas), and that this extraction is occurring in an open system for natural hydrogen systems, whereas it occurs in an almost closed system in petroleum systems.
A simple modelling allows to confirm the open dynamics of hydrogen gas in geological formations, where accumulations are related to bottleneck effect rather than to a complete sealing process. It was also possible to compare the efficiency of this steady-state accumulation in various case studies, as well as the efficiency of hydrogen generation for various geological hydrogen systems.

Hydrogen, whether produced from renewable energies, through stimulating serpentinization, or harvested from natural geological reservoirs, represents a key energy vector and source for the ecological transition toward a net-zero carbon society. Molecular hydrogen is also a key electron donor in diverse microbial metabolisms, and many microorganisms use it as an energy source and convert it into a variety of compounds. Over the last decades of research, we have discovered that subsurface environments harbor a diverse microbial community capable of interacting with hydrogen and other volatiles. These communities are present in virtually all rock types and extend to depths of 5 kilometers or more. The storage of hydrogen underground, whether natural or engineered, presents several challenges, primarily due to its interaction with a diverse and ubiquitous subsurface biosphere. In this talk, I will review our current understanding of the microbiology of natural hydrogen and underground hydrogen storage, highlighting the existing gaps in our knowledge and identifying areas to focus basic and industrial research to make a hydrogen-based society a reality. While natural hydrogen prospecting, orange hydrogen, and underground hydrogen storage have diverse challenges, their microbiology is deeply intertwined and can inform each other reciprocally. I will present new, unpublished microbiology data from hundreds of natural hydrogen springs sampled globally and compare their microbiology with that of porous reservoirs and laboratory experiments, integrating efforts across geosciences, biosciences, and engineering.

Donato Giovannelli, Martina Cascone, Guillermo Climent Gargallo, Gabriella Gallo, Angelina Cordone, Marco Moracci, Davide Iacopini, Mariano Parente, Danilo Russo, Maria Portapillo, Giuseppina Luciani, Almerinda di Benedetto, Alberto Vitale Brovarone

Geological Hydrogen exploration is a complex process that involves understanding both mineral and hydrocarbon systems. This includes the mineral content, fluid conduits, as well as the generation, migration, and trapping of hydrogen gas. To successfully explore for H2 systems, we need to integrate knowledge from these different branches of geosciences.

Xcalibur, having conducted extensive airborne surveys for both sectors, is uniquely positioned to apply its existing Airborne Geophysical tools to aid in the search for geological hydrogen. Currently, the Falcon Gravity Gradiometer Technology is being extensively used to map and evaluate the geology, thereby identifying potential locations for Hydrogen exploration.

However, while the current generation of Airborne Gravity Gradiometer (AGG) systems is well-suited to mapping the vital structural boundaries, faults, structure and basement geology which are critical to Hydrogen systems, their sensitivity and resolution are not sufficient to image more subtle geological features. These features may be crucial at the prospect scale when evaluating H2 accumulation or migration pathways at the prospect/Exploration & Production (E&P) scale.

To address this, Xcalibur and Lockheed Martin are developing the next-generation gravity gradiometer, known as the Condor Airborne Laplacian Gradiometer. This instrument is designed to directly measure the Gravity Tensor at a single point in space, eliminating the need for measurements in a rotating reference frame. With the sub-systems validation component of the program concluded, there is high confidence that the desired performance will be achieved. Modelling has shown that the Condor has the potential to provide low noise data to such an extent that instrumentation noise becomes irrelevant. Condor should provide better quality gravity data than all other airborne and marine and moving-base ground sensor technology.

As a button on to either FALCON or CONDOR, or as a standalone system, Xcalibur has progressed with the development of H-MAS, a Hydrogen Raman Spectrometer. Designed to measure the concentration of atmospheric Hydrogen just above the earth’s surface, H-MAS will be capable of measuring concentrations to a few parts per million. The primary goal of H-MAS is to measure H2 concentrations, it can also be configured to measure methane and a few other gases that exhibit Raman scattering. The recipient of a Curtin University Trailblazer grant to commercialise the technology, the technology, proven in the lab, is moving rapidly to becoming a deployable instrument.

Xcalibur believes that this combination of very high-resolution gravity measurements and the simultaneous deployment of the H-MAS spectrometer provides a unique and powerful tool in the search for Geological Hydrogen

Numerical simulation of sedimentary basins (Schneider et al, 2000) has been developed to assist the geoscientist in building consistent integrated models of the deep subsurface over geologic time and in predicting petroleum systems. Beyond these applications, it seems interesting to ask whether it can also help to address the challenges of hydrogen systems. In this communication, we present some recent developments in numerical basin modeling that tentatively address some of these challenges. A demonstration case is presented and several scenarios about natural hydrogen migration and alteration are considered. To be able to model natural H2 systems, we had to extend and develop new functionalities to simulate migration processes that are usually neglected when considering hydrocarbons: 1. Although already designed for two-phase flow simulation, we needed to implement the exchange of hydrogen between the vapor phase and the aqueous phases. To do this, we rely on an analytical formulation of H2 solubility as a function of salinity, pressure, and temperature, and which was calibrated against the equation of state of Sørreide and Whitson (1992). Using this functionality, H2 exsolution or dissolution along flow paths as thermodynamic conditions change is well represented. 2. Dissolved hydrogen diffusion is also simulated with a diffusion coefficient that depends on porosity, temperature, and facies tortuosity. 3. To model possible influx of H2 by hydrothermal flow, we are now able to impose the influx rate at deep fault roots as well as its dissolved hydrogen concentration. Classical gas production by an order-one degradation process of a source material using an Arrhenius degradation rate is also available in predefined lithologies. 4. Since the degradation kinetics of H2 is also expected to be orders of magnitude faster than that of hydrocarbons, a basic degradation model based on an order-1 process has been implemented according to the model proposed by Rosso (1993), where the degradation occurs only in a temperature range. 5. Finally, our detailed modeling of flow in fault zones which simulates the flow in damage zone cells and across the fault gouge using different discretization cells is particularly well suited to simulating H2 migration which is believed to be largely controlled by flow along faults. Using this updated version of our basin simulator, we developed a demonstration case slightly modified from a 2D section of the Perth Basin in Australia (Frery et al, 2017). This demonstration case shows that predicting hydrogen migration is far from intuitive as it is controlled by many factors, including regional-scale hydrodynamics and thermodynamic conditions, the latter controlling the depth and location of exsolution. This makes basin modeling an essential tool to address natural H2 systems.

Co-auteur : Marie-Christine Cacas-Stentz*, Benjamin Braconnier*, Francesco Patacchini*, Clémentine Meiller*, Arnaud Pujol*, Adriana Traby*, Françoise Willien*, Sylvie Wolf*

Hydrogen directly coming from the Earth could represent an alternative source of decarbonized hydrogen and potentially provide the opportunity to rapidly scale up green hydrogen production for domestic use and export. Exploration programs aiming to find natural H₂ reserves at economic scale are now active worldwide, but the geological contexts favourable to generate and accumulate such gas at depth remain poorly constrained. Hydrogen can be naturally produced by various processes in the subsurface. Here, we review and discuss the generation processes as well as the elements of the hydrogen system through recently investigated case studies located in South Australia and Western Australia.

These case studies, including the well-known Gold Hydrogen Ramsey prospect, integrated new datasets acquired: 1) in the field with soil-gas surveys and ground water analyses around potential natural seeps, and 2) in the laboratory on samples from historic well cores and cuttings to investigate the subsurface geofluid paleo-migrations, the oxidation processes, the generation potential and characterise the geomechanical and transport properties of selected potential sources, reservoirs and seals. Finally, conceptual geological models of hydrogen prospectivity were developed to discuss the weight of each generation process and to integrate the elements of the system at a regional scale. 

Co-authors: Dr. Ema Frery¹, Dr. Julien Bourdet³, Dr. Claudio Delle Piane¹, Dr. Melissa Duque NK¹, Krista Davies^1,2, Dr. Charles Heath¹, Dr. Se Gong¹, Dr. Bhavik Lodhia¹, Dr. Jelena Markov¹, Dr. Mustafa Sari¹, Dr Siyumini Perera¹, Dr. Joel Sarout¹, Dr. Julian Strand¹

1. CSIRO Energy
2. 2. ECU
3. Rocks and Bubbles

This study investigates the properties of natural hydrogen (H2) in two geothermal wells, PX1 and PX2, in the Pohang enhanced geothermal system (EGS) in the Korean Peninsula. Well PX1 has a steady H2 concentration level of ~30 ppm, whereas well PX2 has much higher levels, 6000 ppm at depths of 45 m and increasing at a rate of ~130 ppm/m with depth of 1–45 m. The H2 flux in PX2 is ~871 g/m2/day. Possible source rocks for the generation of H2 include gabbroic amphibolite xenoliths within granodiorite and ultramafic rocks. Thermodynamic modeling yields estimated maximum concentrations of H2 of ~120 ppm and ~900 ppm in the xenoliths and ultramafic rocks, respectively. The difference in H2 concentrations between PX1 and PX2 is ascribed to the different locations of the wells with respect to the position and geometry of the causative fault of the Pohang earthquake. PX1 is located in the hanging wall, whereas PX2 cuts the fault and penetrates the hanging wall and footwall. The impermeable gouge layer(s) and permeable damage zone of the fault are inferred to have sealed and facilitated the migration of H2, respectively. The H2 trap in the Pohang EGS site formed in response to activity along the causative fault and antithetic normal faults that developed during the evolution of the Pohang Basin. The occurrence of H2 reservoirs controlled by fault structures (i.e., structural traps), as observed at the EGS site, should be considered during exploration for economic accumulations of H2.

The Paleozoic ophiolite massifs are widely distributed in Kazakhstan and present a part of the Central Asian Orogenic Belt (CAOB). These ophiolites consist mainly of ultramafic-mafic units, volcano-sedimentary sequences, and basaltic and doleritic lavas. In Western Kazakhstan, the Kempirsai peridotite massif is one of the largest in the south Urals. It contain several mines for podiform chromite ores which are associated with ultramafic lithotypes (dunite and Harzburgite). This study is focused on Khromtau mine in Aktobe region in northwestern Kazakhstan to investigate the distribution of the different peridotite lithotype. The mineralogical and geochemical composition of the peridotite lithotypes were studied in order to define the type and relative abundance of Fe-, mg-bearing minerals as well as the extent of serpentinization and its byproducts (e.g. magnetite, serpentine, brucite) . The investigated peridotite rocks consist mainly chromite- rich dunite enriched in fayalite and forsterite minerals and clinopyroxene. Tiny magnetite crystals are also reported growing on the fayalitic olivine. Lizardite and Fe-brucite are dominant mineral phases observed in the studied peridotite rocks. Mineralogical and geochemical composition of the studied peridotite reveal their significant potential for natural H2 generation via serpentinization. Batch reactor experiment will be conducted to investigate potential hydrogen generation from the Aktobe peridotite at temperatures less than 100°C.

Authors: Mahmoud Leila1,2, Randy Hazlett1, George Mathews1, Milovan Fustic1 1School of mining and Geosciences, Nazarbayev University, Astana, Kazakhstan 2Faculty of Science, Mansoura University, Mansoura, Egypt

Objectives

The serpentinization of the mafic and ultramafic rocks is one of the most significant mechanisms for producing natural hydrogen in the subsurface. The northern part of Borneo is notable for its complex regional geology, particularly regarding Fe-rich rocks in the ophiolite zone of Sabah. This article discusses the mineralogy of ophiolites in Sabah, which could lead to the natural hydrogen feasibility via serpentinization processes.

Methods

Fieldwork was conducted in selected outcrops to investigate the presence of ophiolites, and standard petrography and x-ray diffraction (XRD) analyses were performed on the mineral composition and composition of the rocks. The investigation area includes the ophiolites found in Ranau, Telupid and Lahad Datu, these ophiolites are composed of crystalline basement and ultramafic- serpentinite rocks that are of Triassic to Early Tertiary age.

Results, Observations, Conclusions

The rock samples consist mainly of serpentinite with some basalt, dolerite and amphibolite. These rocks are unconformably overlain by younger sedimentary rocks, including the Eocene-Oligocene Crocker Formation and the Paleocene-Eocene Trusmadi Formation in northern Sabah. In central Sabah, the ophiolite is overlain by the Eocene-Oligocene Crocker Formation and the Kulapis Formation, while the ophiolite in southern Sabah is overlain by the Oligocene-Middle Miocene mélange sequence such as the Kuamut, Ayer and Kalumpang Formations. The results of the geochemical and mineralogical investigations show that the serpentinite samples contain a considerable amount of serpentine minerals (Figure 1) such as antigorite, cronstedtite and lizardite as well as some unaltered ultramafic/mafic minerals (e.g. forsterite, fayalite, pyroxene and hornblende) and traces of secondary minerals (such as magnetite, chromite, hematite, siderite and pyrite). The degree of serpentinization in the serpentinite samples ranges from 25% to 79% by volume, with most samples exceeding 45%. The degree of serpentinization gradually increases from North Sabah (average 45%) to Central Sabah (average 59%) and South Sabah (average 74%). Other rock types such as basalt, dolerite and amphibolite show a lower degree of serpentinization, ranging from 2% to 20%. The laboratory analyses indicate that significant serpentinization processes have occurred along the ophiolite zone of Sabah, which could yield significant amounts of hydrogen gas through the geochemical reactions below:

1.     3Fe₂SiO₄ (fayalite) + 2H₂O → 2Fe₃O₄ (magnetite) + 3SiO₂ (quartz) + 2H₂

1. 6Fe₂SiO₄ (fayalite) + 7H₂O → 3Fe₃Si₂O₅(OH)₄ (serpentine) + Fe₃O₄ (magnetite) + H₂

The overlying sedimentary rock formations could provide reservoir and seal traps for the hydrogen gas accumulation. These results give new insight into potential natural hydrogen resources in Sabah’s ophiolite zone; however, more detailed investigations are needed for further evaluation. Limited subsurface data is a major challenge in studying the entire natural subsurface hydrogen system along the ophiolite zone in Sabah.