A scientific drilling project to investigate natural gas in shale rock recently launched on the Danish island of Bornholm. The GFZ German Research Centre for Geosciences, together with the Geological Survey of Denmark and Greenland (GEUS), completed a shallow drilling project of approximately 130 feet into the Alum Shale of the island within the research project GASH (Gas Shales in Europe, the first European interdisciplinary shale gas research initiative). These dense claystone packages from the Cambrian era are some 500 million years old, and may contain natural gas (methane). Also known as shale gas, this methane is regarded as a so-called unconventional natural gas, and could be an interesting new energy resource for Europe.

Natural gas is referred to as shale gas when it is trapped in shales. Like any methane, shale gas derives from organic matter. Over a period of hundreds of millions of years, deposits of plant debris can decompose to crude oil and natural gas, if they are covered by sedimentary deposits under the necessary pressure and temperature conditions. In the case of shale gas, the process differs somewhat: Before it can seep into larger reservoirs, it is trapped in the rock. For this to occur, the rock must be compact – composed of very small individual grains – and shale has such properties. Shale gas deposits are considered unconventional because, in contrast to conventional oil and natural gas systems, the gaseous claystone package provides three individual functions – as the mother rock in which the gas is formed, as a reservoir rock in which the matured gas is stored and as a cap rock that prevents the methane from escaping.

Scientists at the GFZ investigate these processes and potential deposits in Europe in the international-scale research program GASH, because the geological conditions that lead to the shale gas formation and preservation in Europe, as of yet, have not been explored very well. The drilling on Bornholm is intended to improve the knowledge on this subject, by analyzing the obtained cores with geological, geochemical, geophysical and geomechanical methods. To this end, the mobile laboratory "BugLab" of the GFZ will be transported to Bornholm.

The drilling took about 3 days. In order to validate the results, a second core was drilled close to the first borehole, which will remain with the GEUS in Denmark. Finally, the drilling was followed by geophysical examinations using 3-D seismics and water samples.

Eleven individual projects are implemented in the joint research project GASH. In addition, GASH is developing a European-wide black shale database that for the first time combines all the available geological information on black shales in Europe. Research partners are the German GeoForschungsZentrum GFZ and several European universities and research institutions. The GASH project will run over a 3-year period (2009 to 2012), and is coordinated by the GFZ.