The storage of carbon dioxide (CO2) in saline aquifers is one of the most promising options for Europe to reduce emissions of greenhouse gases from power plants to the atmosphere and to mitigate global climate change. The CO2SINK project is a R&D project, mainly supported by the European commission, the German Federal Ministry of Education and Research, and the German Federal Ministry of Economics and Technology, targeted at developing an in situ laboratory for CO2 storage. Its aims are to advance the understanding of the processes involved in underground CO2 storage, evaluate applicable monitoring techniques, and provide operational experience, which all contribute to the development of harmonized regulatory frameworks and standards for CO2 geological storage.
The preparatory phase of the project involved a baseline geological site exploration and the drilling in 2007 of one injection and two observation wells, as well as the acquisition of a geophysical baseline and geochemical monitoring, in Ketzin located near to Berlin, Germany. The target saline aquifer is the Triassic Stuttgart Formation situated at about 630–710 m (2070–2330 ft), that is made of siltstones and sandstones interbedded by mudstones. A comprehensive borehole logging program was performed consisting of routine well logging to which an enhanced logging program was added for one well that record nuclear magnetic resonance and borehole resistivity images predominantly to better characterize the storage formation. A core analysis program carried out on reservoir rock and caprock included measurements of helium porosity, nitrogen permeability and brine permeability. Carbon dioxide injection started in 2008 and will last for about 2 years.
The paper focuses on the integrated approach of combining lithological and petrophysical data from both laboratory and well logging analysis predominantly for the reservoir/storage section of the Ketzin site. This method was successfully applied in two wells with extensive core data. In the third well, where few core data exist, the section was characterized successfully by analogy.