Subsurface Laboratories

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

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

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.

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.