Mobilisation of Unconsolidated Sediments Related to CO₂ Storage

Begin of project: March 1, 2013

End of project: December 31, 2017

Status of project: January 1, 2018

In many sedimentary basins, including the North Sea Basin, mixtures of natural gas, formation fluids and sediment discharge at the earth surface or at the sea floor. Various processes can induce the mobilization of unconsolidated sediments that lead to the formation of ‘seismic chimneys’, mud volcanoes at the earth surface or ‘pock marks’ at the sea floor.

Mudvolcano discharging gas, formation water, crude oil, and fine-grained sediment in the Northland Basin, New Zealand Source: F. May

These presence of such features next to proposed or operating storage sites in the North Sea implies questions about the safe storage of CO₂:

• Are the wide-spread sediment deformation structures potential pathways of enhanced permeability facilitating leakage of fluids?
• Could the injection of CO₂ result in elevated pore fluid pressures sufficient to trigger the formation or reactivation of sediment deformation structures?  

Answers to these questions are sought by means of laboratory experiments at the Friedrich-Schiller University in Jena. These experiments facilitate a better understanding of the processes of soft sediment deformation and the quantification of key controlling parameters. Knowledge of these processes and the controlling parameters will aid the targeted exploration of storage sites, prediction of storage processes and storage safety in general.

Literature:

Final Report: Sediment mobilization and associated risks for CO₂ Storage (in German).

Data sheets of the experiments described in the final report are available in English

Partner:

Institut für Geowissenschaften der Friedrich-Schiller-Universität Jena