Sorry for the delay, but here my highlights of the last two days of EGU 2014!
While there were some interesting sessions going on on Thursday morning I used it to write the blog entry on days two and three as well as for preparing for the presentation I was about to give just after lunch break. The session was on “Field methods and analysis of field data for CO2 geological storage” and I have to admit that I was much more nervous than I had anticipated given the fact that I have given a similar presentation just a short while ago and that I had given a presentation at EGU the year before. But thankfully all went all right, if you refrain from the fact that my talk was only 10 minutes instead of the planned 12 minutes long. But that way I had time to answer some more questions!
There were some (other ;-)) good talks in the sessions and I want to focus on a few here:
CO2 Storage Atlas Norwegian Sea
With CCS getting more attention in Norway the Norwegian Petroleum Directorate (part of the Ministry of Petroleum and Energy) created three big atlases on offshore areas around Norway (North Sea, Norwegian Sea and Barents Sea) in which they identified safe and effective areas for long-term CO2 storage. The atlases can be found online. One of the main objectives of the research was to make sure that CO2 storage sites would not interfere with current and future hydrocarbon exploration and production activities – this made the project more challenging and rendered large areas unsuitable.
The presentation by Rita Sande Rod was on the Norwegian Sea and how she and her team identified several formations/aquifers as potential storage sites. Most of the targeted saline aquifers dip with 1-2 degrees from the Norwegian coast towards offshore regions and one concern is that injected CO2 might migrate updip towards the coast where it may leak into the sea. However, they could show that when injecting 400 million tons of CO2 over 50 years most of the gas will have gone into solution or will be residually trapped long before it migrated updip. Their simulation of the CO2 plume lasted for 10.000 years and covered different injection locations and injection rates but for none of the simulations leakage would occur. This is good news for future CO2 storage offshore Norway!
Effects of CO2 leakage on benthic biogeochemistry
In May 2012 a really exciting experiment took place at the Scottish coast: Scientists drilled a well into the seafloor and released CO2 12m below the seafloor to study the impact leakage from a CO2 storage site would have on the ecosystems in seafloor and the sea itself. The release of CO2 lasted for 36 days and was continuously monitored via a wide range of methods. Overall 4.2 tonnes of CO2 was injected, which is a very small amount compared to natural degassing of CO2 that can be observed in volcanic areas or above natural CO2 reservoirs. However, the controlled release made it possible to study the impacts in detail and many scientists from all over the globe were involved in the project, which was the first of its kind.
As expected some of the CO2 was leaking as gas bubbles soon after the injection started and the chemistry of the water in the seafloor and the sea changed over time. While the impact on marine ecosystems directly at the point of leakage were altered, the impacts dissipated rapidly with distance away from the release point. Upscaled to a “real” leak this means that the area affected by CO2 would be less than 50 meters across. And, for me one of the key findings of the study, after the leakage has been stopped (in this case after the injection stopped) the ecosystems quickly recovered! However, it should be kept in mind that this is true for the ecosystems that can be found in Scottish waters and not necessarily true for carbonate-rich habitats such as coral reefs.
Using pressure data to identify migration of CO2 in a reservoir
One of the main current research areas within CCS is the monitoring of the CO2 plume during and after injection in the reservoir. This is because we want to know where the CO2 is going so we can be sure that it is not migrating out of the reservoir. There are many different methods on how this can be done, from geophysical approaches like seismic (4D ideally) or resistivity to geochemical techniques that measure the arrival of the CO2 plume directly.
Christin Strandli from Stanford University presented a method I haven’t heard much about before the conference: Using several stacked (multilevel) transient pressure detectors she and her team were able to track the migration of the CO2 plume in the CO2 storage site of the Illinois Basin Decatur Project. The idea behind the method is that the initial pressure within the reservoir changes once CO2 injection starts as the CO2 displaces the formation water close the the injection well. This pressure build up can be measured in a monitoring well away from the injection site well before the CO2 actually arrives at it. With this method it is also possible to create a good hydrogeological model of the reservoir which in turn can than be used to predict the future CO2 migration!
After a long week this was the last day! I was pretty saturated with all the science so I took the morning off for some sightseeing!
During lunch time I had an interview with Laura Roberts who is the author of one of the EGU blogs. The interview should be online in the next few weeks, I’ll let you know when.
In the afternoon I went to some sessions on geothermal energy and hydropower where I learned a lot about the many things there are to know about those fields! There were several talks about geothermal energy in Ireland which was quite surprising to me as I hadn’t pictured Ireland as a hotspot for geothermal energy! But it turns out that there are shales and granites that have a lot of radioactive elements (U, Th, K) which produce heat when they decay.
So far so good, I hope you enjoyed the entries on my EGU experience! Let me know if you have any feedback.