Geochemical Sampling

Micro-seepages of hydrogen can be detected in the earth’s soil and serve as crucial indicators of subsurface hydrogen reserves. Geochemical surveying involves collecting and analysing surface soil samples in a designated area to look for surface anomalies, specifically areas with high levels of hydrogen micro-seepage.

If such anomalies are present in a particular surveying area, their shape can help identify the hydrogen source. Geochemical anomalies reveal the end point of a seepage route, which can be directly above hydrogen deposits in geologically simple areas, or in more complex regions, they can be up to 100 km away from the source, where transverse seepage has occurred.

Geochemical samples provide a good indication of the existence of hydrogen deposits and, when coupled with an understanding of the underlying geology, can help locate these deposits. Additionally, these samples offer insights into the composition of the hydrogen source.

Over the past five years, we have conducted geochemical surveys of our Namibian hydrocarbon concession. We employed Geofrontiers, a Texas-based geochemical exploration company, to collect and analyse soil samples from our two concessions. Using acid extraction techniques, the presence of hydrogen and associated gases was investigated. Their report found significant concentrations of these gases in several regions of the concession. The green patches in figure 10 represent anomalies with 100 times the background concentration.

In a second round of tests, the ratio of different gases (such as hydrogen to methane and other hydrocarbons) was examined to better understand the seepage source of the micro-seepages.

These second tests were conducted in sample areas with particularly high concentrations on the concession. The ratios indicate that the hydrogen was produced by a thermogenic process (high temperatures at great depths) rather than through biogenic processes, which can create gases at the surface. Furthermore, these ratios suggest that light hydrocarbons are the most likely source from which the hydrogen migrated to the surface.