GEUS’ Laboratory for Organic Carbon, including biochar, has extensive experience within organic petrological and geochemical analysis of organic carbon, such as biochar, source rocks, coal, and oil. The laboratory conducts pure research projects, offers its services on fully commercial terms, or participates in collaborative projects.

Founded in 1978, the laboratory has developed from a primarily coal-and petroleum-oriented unit into a full-fledged organic petrographic and geochemical laboratory specialized in characterisation of biochar, dispersed organic matter in rocks and coal, and petroleum. Contact us to hear more about our expertise.

Work fields

Prominent fields of work include stability assessment of biochar by reflectance measurements and geochemical characterisation, petrographic morphotype characterisation of biochar, petrographic and geochemical examination of terrestrial, lacustrine and marine organic-rich rocks and coals by maceral analysis, and organic maturity assessment by vitrinite reflectance. The work field also includes bulk composition (Sat/Aro/Polars) and gas chromatography (GC) of organic solvent extracts, including remaining oil in depleted oil fields, and crude oil.

Analytical services

The Organic Petrography section of the laboratory is dedicated to the petrographic study of biochar, dispersed organic matter (DOM) in sedimentary rocks, and coals by maceral analysis and reflectance measurements.

The laboratory has extensive experience in making particulate blocks (pellets) of various types of organic matter for incident light microscopy. The laboratory is equipped with several incident light microscopes with facilities for determination of the carbonization temperature and stability of biochar by reflectance measurements, the rank/maturity of coals and DOM by means of vitrinite reflectance measurements, and the organic petrographic composition of biochar, DOM and coals by combined white/blue light maceral analysis. For random reflectance measurements, the Hilgers Fossil system is used.

The laboratory has extensive expertise within biochar morphotype characterisation, and organic facies analysis of organic-rich deposits, source rocks and coals related to the interpretation of the original depositional environment and to the evaluation of source rock potential.

Geochemical services offered include organic geochemical screening analysis as well as more advanced analyses. Screening analyses available include Total Carbon (TC), Total Organic Carbon (TOC), Total Sulphur (TS), and Rock-Eval-type pyrolysis using the  the HAWK (Wildcat Technologies) that yield data corresponding to those produced by the Rock-Eval™.

Further analyses include solvent extraction using a Soxtec™ apparatus and group type fractionation by Medium Performance Liquid Chromatography (MPLC) and Gas Chromatography (GC).

Exstensive research and service to authorities and industry

The laboratory has contributed to both basic and applied research within a variety of fields in more than 30 different countries on five continents, provided extensive service to Danish authorities and carried out numerous consultancy projects for the petroleum industry and others.

Current research projects include:

• CO2RESHC – Evaluation of residual hydrocarbons effect on CO2 injectivity in depleted chalk reservoirs (INNO-CCUS project)
• BIOCHSTA – Documentation of long-term carbon stability in biochar (INNO-CCUS project)
• Investigating carbon permanence of biochar; influence of feedstock type and pyrolysis method on the long-term stability of biochar (Geocenter Denmark project)
• Model for implementation of biochar in the emission inventory and climate projection (Ministry of the Climate, Energy and Utilities project)

In the PALEOClimate laboratory, we study environmental and temperature changes in the geological past using organic molecules (biomarkers) produced by various microorganisms.

Identification of organic compounds can help to identify the source of organic matter as well as trace ecological changes in oceans, lakes, or terrestrial settings (e.g. Lupien and Sliwinska, 2025). Understanding changes in the climate and environment can be crucial in studying depositional settings and basin development. Our laboratory carried paleoenvironmental analysis for research purposes, as well as applied science, e.g. for   groundwater mapping projects.

We can analyze among others:

• Changes in primary productivity (e.g. phytosterols, alkenones, chlorins, and diols)
• Hydrocarbons (petroleum hydrocarbons are one of the most common environmental contaminants)
• Temperature evolution (alkenones, HBIs and membrane lipids - the most commonly applied biomarkers for the past temperature evolution carried in our laboratory includes membrane lipids (GDGTs, TEX₈₆; e.g. Śliwińska et al., 2014, 2023) and long chain alkenones (Uk37; e.g. Herbert et al., 2020).

Our laboratory is equipped in ETHOS X Advanced Microwave Extraction System, as well as TurboVap® and FlexiVap™ solvent evaporators. We also host GC-FID/MSD (GLOBE) and HPLC-MS (Agilent 1290 Infinity II LC and InfinityLab LC/MSD XT). Our laboratory has a capacity to process large volumes of samples using state of the art equipment.

Our laboratory welcomes students and guest researchers who are interested in collaborating with us.

Current projects:

• Denmark under IPCC scenarios – a view from the Eemian and Miocene past warm periods (EeMi) (2024-2027) funded by Geocenter Denmark
• Past to future: towards fully paleo-informed future climate projections (P2F) (2025-2029) – website coming funded by Horizon Europe

Core Flooding and Special Core Analysis Laboratory

Advanced Flooding Experiments
Flooding experiments are performed under reservoir conditions to evaluate changes in petrophysical and mineralogical properties, as well as variations in pore fluid chemistry. These tests are tailored to project-specific requirements. Our equipment typically operates at pressures up to 69 MPa (10,000 psi) and temperatures from 25°C to 125°C, with extended temperature ranges (5°C to 150°C) available for select applications.

We can perform simultaneous measurements of differential pressure and two-phase acoustic saturation, along with high-pressure density assessments. Additional capabilities include water-CO₂ alternate injection, multi-tap pressure recording along the core, studies of capillary backflow effects, and high-pressure geochemical sampling for further analysis.

Capillary Measurements
Capillary measurements are conducted using the porous plate technique, allowing the generation of drainage and imbibition curves at room or reservoir temperature and under overburden pressures. Samples are mounted in single-core holders. Mercury Injection Capillary Pressure (MICP) measurements can be arranged through a subcontractor.

Steady-State Relative Permeability Measurements
Our recently developed setup includes a multi-tap pressure core holder equipped with high-pressure, high-precision pumps suitable for closed-loop fluid circulation. This system supports steady-state relative permeability measurements and is designed for CO₂ and corrosive fluids. It operates at pressures up to 69 MPa (10,000 psi) and temperatures from 25°C to 125°C.

Special Permeability Measurements
We offer specific and endpoint permeability measurements under various conditions using different fluids. These tests cover a wide range of materials, including chalk, sandstone, till, caprock, and unconsolidated sediments. For caprock, entry pressure can be determined; for unconsolidated materials, permeability and effective porosity can be assessed. We also provide mini-permeametry as part of our services.

Wettability Measurements
Wettability measurements are conducted at room temperature using Amott’s method.

Overburden Measurements
Overburden measurements at room or reservoir temperatures evaluate the influence of confining pressure on porosity, permeability, and electrical properties.

Whole-Core Measurements
We offer a limited range of SCAL measurements on whole-core samples with diameters from 54 mm (standard rock mechanics size) to 123 mm, and lengths up to 300 mm, under confining pressures up to 69 MPa (10,000 psi). For overburden pressures up to 1 MPa (145 psi), we can accommodate samples up to 500 mm in diameter.

Electrical Measurements
Electrical measurements at room or overburden conditions assess core conductivity and Archie parameters, including resistivity index, formation factor, cementation exponent, and saturation exponent.

R&D Projects
Our laboratory undertakes research and development projects funded by foundations, research councils, and industry. We collaborate with research institutes in Denmark and internationally. A few of our recent and current projects include:

Recent Projects:

• Project Greensand (2021–2023): Demonstrating that depleted oil and gas reservoirs in the Danish North Sea can be used for safe, long-term carbon storage. Several experimental studies are underway to determine key parameters for accurate reservoir simulation and field development forecasting.
• Project Wintershall (2023–2024): Investigating the compatibility of chalk with CO₂-enriched water injection and its potential to further reduce residual oil saturation (Sor). Multiple experimental studies and in-situ sampling were conducted to assess chemical reaction effects.
• CO2RESHC (2022–2024): Studying the effect of residual hydrocarbons in non-flooded and water-flooded chalk reservoirs on CO₂ injectivity. This work will help de-risk depleted oil fields for CO₂ storage and may significantly influence emission reduction efforts in Denmark.

Current Projects:

• CO2FLOW (2023–2026): Establishing laboratory procedures for determining key parameters of CO₂ injection into geological formations, including relative permeabilities and capillary pressure curves, using standard core-flooding laboratory equipment.
• ChalkCO2RE (2022–2025): Providing fundamental knowledge to advance CO₂ storage in oil/gas fields with chalk reservoirs. This involves integrating geochemical and physical experiments, petrographic investigations, and numerical modelling.
• INNO_SALT (2023–2027): Conducting experimental studies on various scales to improve understanding of how salt precipitation affects injectivity. Successful methods and equipment from this project could become industry standards for optimising CO₂ storage.

Chemical Reaction Tests

At GEUS, we perform specialized chemical reaction tests to understand how geological materials respond to varying fluid compositions, temperatures, and CO₂ concentrations under both static and dynamic conditions. Our focus is on revealing the intricate interactions between rocks, cement, and fluids, enabling us to predict changes in porosity, permeability, and mineral composition in realistic subsurface environments.

In static tests, samples are exposed to controlled fluid conditions for extended periods, allowing us to observe long-term mineral dissolution, precipitation patterns, and the formation of alteration products. Dynamic tests simulate fluid flow through samples, reflecting conditions akin to geothermal circulation or CO₂ injection. By carefully adjusting temperature, pressure, and fluid chemistry, we can track how mineralogy and pore structures evolve over time.

These chemical reaction tests are essential for advancing geothermal energy production, helping to optimize sustainable heat extraction by understanding fluid-rock interactions. Similarly, the insights gained are invaluable for Carbon Capture and Storage (CCS) projects, ensuring secure, long-term CO₂ storage without undesirable geochemical reactions that could compromise integrity.

To complement our experimental work, we employ PHREEQC modeling to establish thermodynamic constraints and calibrate the chemical systems under investigation. We then integrate the resulting data into TOUGHREACT simulations to perform predictive long-term modeling. This combined approach ensures robust, science-based guidance for resource management and the enduring integrity of subsurface energy solutions.

Standard Core Analysis

At GEUS, we offer a range of standard core analyses to determine the petrophysical properties of rocks. Our analyses are performed on Ø25 mm or Ø38 mm plugs or plug trims. The laboratory is equipped with an UltraPoroPerm 500 setup.

Our standard core analyses include:

• Cutting of specimens: Precise cutting and preparation of core samples for subsequent analyses.
• Cleaning (Soxhlet), porosity, and grain density: Removal of hydrocarbons and other substances using Soxhlet extraction, followed by measurement of porosity and grain density.
• Cold flush cleaning of 38 or 54 mm specimens: Gentle cleaning of larger core samples to preserve their structure for further analyses.
• Gas permeability: Determination of the rock's ability to allow gas to pass through, which is crucial for understanding fluid flow in the reservoir.
• Klinkenberg permeability (in addition to gas permeability): Correction of gas permeability measurements for the slip effect at low pressures, providing a more accurate determination of permeability.
• Dean Stark fluid saturation (including porosity): Determination of fluid saturation and porosity using Dean Stark extraction, essential for assessing reservoir properties.
• Our standard core analyses provide vital data for understanding reservoir capacity and characteristics. By combining these analyses with our expertise in petrophysics and geology, we ensure a comprehensive characterisation of the subsurface potential for projects in oil and gas, geothermal energy, and CO₂ storage.

Our services are also employed in the Greens Transition Project, contributing to sustainable energy solutions.

Fossil Preparation

At GEUS, we carry out specialized preparation and analytical tasks within biostratigraphy. Our laboratory processes material from boreholes and outcrops and has the capacity to handle large sample volumes under high standards of quality and safety.

We work with a wide range of microfossils (e.g., dinoflagellate cysts, spores and pollen, foraminifera, diatoms, radiolaria, nannoplankton, conodonts) as well as macrofossils (e.g., bivalves, ammonites, belemnites, trilobites). The preparation includes cleaning, sorting, and concentrating the fossil material to ensure it is suitable for subsequent biostratigraphic analyses.

In addition to preparing fossils from geological periods, we also process samples from Quaternary and modern deposits. For example, we can extract and analyze pollen, diatoms, dinoflagellate cysts, and foraminifera from both marine and terrestrial environments. These analyses contribute to the understanding of past environments, climate changes, environmental history, and are valuable in geoarchaeological research.

Our laboratory methods are carefully selected to ensure high data quality. For instance, we offer relative and qualitative pollen analyses, pollen trapping (monitoring) preparation, diatom analyses of freshwater and marine sediments, as well as macrofossil analyses of Quaternary deposits.

Contact us to learn more about how we can assist with fossil preparation and related analyses.

Integrated sediment petrography laboratory

We provide custom-made reservoir characterization studies for CCS, geothermal energy, heat storage, hydrogen, helium, and hydrocarbon applications. Our work bridges academia and industry, and we maintain close collaborations with both.

Services:

• Petrographic characterization and assessment of diagenetic changes in siliciclastic and carbonate sediments using traditional and advanced microscopy.
• Evaluation of reservoir quality in siliciclastic and carbonate rocks.
• Quantitative grain-size distribution analysis in siliciclastic sediments based on thin-section petrography.
• Automated Quantitative Mineralogy (AQM) of siliciclastic and carbonate rocks.
• Detailed petrographic characterization of fine-grained carbonates and siliciclastic deposits (e.g., mudstones, diatomites) using SEM.
• Carbonate microfacies evaluation for interpreting depositional environments.
• Identification of cement growth zones with cathodoluminescence microscopy.
• Provenance analysis using detrital U-Pb geochronology and heavy mineral composition, combined with petrographic indicators.
• U-Pb dating of authigenic mineral phases.
• Diagenetic temperature estimates from fluid inclusion measurements in quartz and feldspar overgrowths.

Equipment:

• Optical microscopes with transmitted and reflected light (Zeiss and Leica)
• Pelcon point counting stage
• Fluid inclusion heating/cooling stage (Linkam and Leica ICC50W)
• Cathodoluminescence system (Leica DMLP with CL8200 Mk5-2)
• Scanning electron microscope (Zeiss SIGMA 300VP SEM) with EDX, SE, BSC, and CL detectors

Examples of ongoing and past projects:

• ChalkCO2RE – Chalk–CO₂ reactions at reservoir conditions
• CO2RESHC – Evaluating residual hydrocarbons on CO₂ injectivity in depleted chalk reservoirs
• Project Greensand
• Suprabasins – Sedimentary response to growth of major extensional fault systems
• Geological evolution of the Northern margin of the Permian–Triassic Basin in NE Greenland
• North Sea Jurassic Petroleum System
• GEOTHERM – Removing obstacles for large-scale geothermal energy use
• CO2 Upslope – Optimized CO₂ storage in sloping aquifers

At GEUS, we specialize in seal and caprock analysis as part of our research and consultancy services for Carbon Capture and Storage (CCS) projects. Understanding the properties of caprocks, which act as impermeable barriers above reservoirs, is essential to ensure the safe and long-term storage of CO₂. Our laboratory routinely handles materials such as drill cores, cuttings, and outcrsamples for detailed analyses that help evaluate the integrity and sealing capacity of these formations.

Importance of Seal and Caprock Analysis
For CCS projects to be successful, the integrity of the seal formations (caprocks) is crucial. These formations must effectively trap CO₂ in the underlying reservoirs, preventing leakage into the atmosphere. At GEUS, we investigate the mineralogical, petrophysical, and geochemical properties of these seals, focusing on their ability to withstand the pressure and chemical interactions associated with CO₂ storage.

Our studies involve both laboratory experiments and field data collection. We assess key properties such as porosity, permeability, and mineral composition, which are critical for determining whether a formation can serve as an effective barrier to CO₂ migration.

Projects Utilizing Seal and Caprock Analysis
One of the major CCS projects where seal and caprock analysis is critical is the EUDP-funded Greensand project. This initiative focuses on safely storing CO₂ in the depleted Nini West oil field in the Danish North Sea. Handheld XRF is used to analyze core samples from the field, contributing to a detailed evaluation of the sealing capabilities of formations such as the Eocene–Miocene Horda and Lark formations

Numerical Simulation

At GEUS, our numerical simulation capabilities are integral to bridging the gap between laboratory-scale experiments and field-scale reservoir management. We build upon the results of advanced core tests—such as steady-state and non-steady-state flooding experiments, chemical reaction studies, and wettability evaluations—to develop dynamic models that accurately reflect subsurface conditions.

A key aspect of our workflow involves history matching core experiments to ensure that the models replicate observed laboratory outcomes. Through this process, we refine relative permeability curves, incorporate geochemical reaction data, and represent fluid-rock interactions under realistic reservoir conditions. These calibrated parameters and insights enable us to capture the complex interplay of multiphase flow, component transport, and mineral transformations within the reservoir.

Once the core-scale understanding is established, we translate these findings into inputs for full-field reservoir simulators. We employ a suite of industry-standard tools, including ECLIPSE (both the black-oil ECLIPSE 100 and the compositional ECLIPSE 300) and CMG GEM, renowned for their ability to handle complex compositional simulations. By leveraging these simulators, we can predict long-term reservoir performance, assess strategies for enhanced oil recovery, CO₂ storage, or geothermal extraction, and evaluate the potential impact of different field development scenarios.

Ultimately, our numerical simulations provide reliable, science-based guidance, reducing uncertainty and improving decision-making throughout the reservoir lifecycle

At GEUS, we utilize advanced technology to analyze drill cores from both loose sediments and hard rock formations. One of the most important methods we employ is core scanning using the Geotek Standard Multi-Sensor Core Logger (MSCL-S). This technology allows us to collect detailed physical and geochemical data in a non-destructive manner, meaning the core remains intact throughout the analysis

Why Do We Use Core Scanning?

Core scanning is an essential method for understanding the physical properties and composition of the subsurface. By collecting data on density, porosity, magnetic susceptibility, and naturally occurring gamma radiation, we gain insights into layering, mineral content, and geological structures. This information is crucial for assessing geological resources and the reservoir potential of the subsurface, such as in geothermal energy, CO₂ storage (CCS), and resource mapping. Core scanning helps evaluate the subsurface potential and contributes to both research projects and commercial applications, including geological consulting and offshore environmental prospecting.

What Can the Core Scanner Do?

The MSCL-S core scanner is a modular system capable of handling drill cores up to 1.5 meters long, scanning both whole and split cores. The system can quickly and accurately collect the following types of data:

Natural Gamma Radiation: Sensors measure the occurrence of natural gamma radiation from elements like potassium (K), uranium (U), and thorium (Th) within the core. These data are useful for evaluating mineral content relevant to mineral extraction and resource assessment.
Magnetic Susceptibility: The MSCL-S measures how susceptible the core is to magnetism. This can reveal the presence of specific minerals and help understand the geological processes that have shaped the core.
Imaging: A GeoScan V-line scan system produces detailed images of the core's surface, allowing geologists to visually identify layering and structures, which can be important for marine resource projects, among others.
Density and Porosity: Using a gamma density meter, we obtain information about the core's density and porosity—crucial for understanding how fluids like water, oil, or CO₂ move through the subsurface. This is particularly important in CO₂ storage projects and geothermal energy.
The MSCL-S system enables simultaneous data collection from multiple sensors, making the analysis fast and efficient. Data are depth-encoded and presented in real time, allowing researchers to analyze results immediately after scanning.

Examples of Projects Where Core Scanning Is Relevant

• CO₂ Storage (CCS): Core scanning is used to assess the geological conditions necessary to ensure that CO₂ can be safely stored underground without the risk of leakage. GEUS works on mapping and evaluating Danish subsurface reservoirs for this purpose.
• Marine Resource Mapping: In the exploration of seabed resources like sand and gravel, core scanning is essential for understanding sediment layers and their composition. GEUS is involved in mapping resource occurrences in Danish waters.
• Geothermal Energy: Exploiting geothermal energy requires a detailed understanding of the subsurface reservoir properties, such as porosity and permeability. Core scanning helps identify the best areas for extracting heat from the subsurface.
• Environmental Prospecting: In studies of the marine environment, including pollution monitoring, core scanning provides precise data on sediment composition and environmental conditions, which is necessary for understanding and protecting the marine ecosystem.

Through core scanning, GEUS effectively contributes to solving key challenges in geological research and industry, from resource mapping to ensuring sustainable energy solutions.

GEUS is equipped with a Niton XL3t GOLDD+ handheld XRF device, a highly versatile tool for semi-quantitative elemental analysis of up to 44 elements. This advanced instrument, operating with a silver (Ag) anode at voltages ranging from 6 to 50 kV, can be used both in the field and the laboratory, providing rapid, non-destructive analysis directly on rock surfaces, core samples, and crust materials.

The handheld XRF is particularly useful for mineral investigations and subsurface characterization. Its speed and efficiency make it ideal for screening large volumes of samples, allowing geologists to quickly identify representative samples for further, more detailed analysis. In typical workflows, the XRF is employed for rock typing and to provide initial insights into the properties of reservoirs and seals, contributing to the evaluation of sites for CO₂ storage and other subsurface applications.

Projects Utilizing Handheld XRF from GEUS Laboratories

The EUDP-funded Greensand project, a groundbreaking initiative in Carbon Capture and Storage (CCS), uses handheld XRF to analyze core samples from the Nini Field in the Danish North Sea, contributing to assessments for safe CO₂ storage. Similarly, the CCS 2022-2024 project and the SHARP project benefit from XRF analysis to evaluate geological formations for the same purpose.

At GEUS, our petrophysical analysis combines data from well logs and core samples to deliver a thorough evaluation of subsurface formations. We identify different lithologies that are important in the rocks petrophysical parameters, such as porosity, and permeability, offering insights into the rock’s ability to store and transmit fluids.

Our well log analysis provides continuous data over the entire wellbore, allowing us to determine properties like porosity and shale content, while our core plug analysis offers high-resolution measurements on specific samples. All core plug data are stored in a detailed database, ensuring easy access to reliable information for future studies.

By integrating well log data, core plug measurements, seismic data and understanding of the overall geological history, we produce interpreted datasets that offer a comprehensive understanding of the reservoir such as lithology and facies distribution. This integrated approach is essential for CO₂ storage (CCS) and geothermal energy projects, where accurate knowledge of reservoir properties ensures optimal storage or fluid flow.