The aim of this project was to develop technologies related to CO2 storage and safety, in particular the storage of CO2 in shallow aquifers.
For monitoring the CO2 injection, a new 3D DC/IP acquisition system was developed. The system encompasses 5 relay boxes for surface measurements allowing the acquisition of regular 2D sections and cross measurements involving different relay boxes for a full 3D coverage, used in combination with optimal addressing schemes (acquisition protocols). In addition, a 6th relay box was used for the measurement of borehole data.
Example of relay box newly developed at the Aarhus University for 3D measurement of IP/DC data
320 electrodes were set up over 5 profiles (2 m spacing). The acquisition system was permanently installed prior to the CO2 injection for the collection of background information until October 2012. The injections were performed at the beginning of May 2012 through two spots at 5 and 10 m depth, with a ratio of 8L/min (then reduced to 3L/min), during 2 months, until end of July 2012. A newly developed hardware allowed remotely launching the acquisition system and transferring the data using the 3G network. Totally more than 200 complete 3D datasets in IP/DC could be collected. Currently, the efforts are dedicated to the development of an automatic process, filtering the data in time and space. In parallel, new inversion schemes are being implemented for inverting 2D and 3D time-lapse data.
Sketch of 3D acquisition setup