“Clay compaction, overpressure, and how to link two very different projects”
Abstract
One of the ongoing projects in the section for Geotechnics and Geology is the forward modelling of overburden compaction in the North Sea.
Clay rich deposition during the last ca 60 Ma dominate the overburden in the North Sea. In order to calibrate the modelling, we need a good analogue.
For this purpose, we choose to use data from the Ocean Drilling Project since these boreholes contain parameters such as sonic velocity, grain density and porosity with very high resolution.
We choose The ODP site 646, since its location in the Davis Strait between Greenland and Canada yields a lithology of the ca. 800 m of core of predominantly clay, with minor silt intervals. This is very similar to the clay prone overburden observed in the North Sea during the Cenozoic. However, other boreholes was also evaluated, including ODP Site 913.
This borehole is located on the Northeast Greenland shelf, an area part of a completely unrelated study. Here it was observed that overpressure was present in the clay rich intervals, thus yielding important, unpublished information about the depositional history of the Northeast Greenland shelf.