I know I said I would write a short report every day, but somehow I just did not have time! Too much science and socializing… but here my highlights of day 2 and 3 of the EGU 2014.
Tuesday started not very well. Just about made it to the conference in time for the 9.15 talk on CO2 EOR from a fellow Edinburgh PhD student after making it through the subway system during rush hour only to find out that several speakers in his session hadn’t shown up and he had given his talk 30mins earlier. From the 8 talks I attended over the course of the day two were intriguing. That is actually a pretty good ratio, I have seen to many uninspiring talks here 😦
CO2 storage in gashydrates
Did you know that there is the possibility to store CO2 in gas hydrate form while at the same time increasing the production of methane from gashydrates? It never crossed my mind before I saw presentation on simulating subsea gas hydrate exploration! While the actual implementation of this theory is not going to happen any time soon, it was good to see that there are CO2 storage options that increase the production of hydrocarbons other than EOR/EGR. Of course using less hydrocarbons would be much better, but I am afraid that we will be dependent on them for a little while longer. The idea is that CO2 displaces CH4 in the gas hydrate and this might work because the CO2 hydrate has a bigger stability field. Using CO2 shows a significant boost in production after four years, while initially there is not much difference.
Sills as fractured hydrocarbon reservoirs
Normally you (or at least I) think about carbonates and sandstones when you hear hydrocarbon reservoir. However, a talk by Zoe Barnett from Royal Holloway University of London opened my eyes for a new world of reservoirs: Sills! Sills are rock bodies, often lens shaped, that are implaced by magma intruding into sedimentay successions. The Salisbury Crags at Arthur’s Seat in Edinburgh are such a sill. Normally you wouldn’t expect magmatic rocks to form reservoir because they often have low porosities and permeabilites but if they have been deformed by tectonic stress they often have a lot of fractures. Depending on how many fractures there are per area (also called fracture density), magmatic rocks can form good fractured reservoirs: Instead in pores the hydrocarbons are found in the fractures.
The interesting things about sill is that they can be reservoir and seal at the same time: At the contact between magma and host rock (the sediment the magma intruded into) one can find baked and chilled margins that have a low permeability. Baked margins are the bits of the sedimentary rock that have been in direct contact with the hot magma and have undergone mineral transformations. Chilled margins are the outer layer of the sill which have cooled rapidly because they have been in contact with the cold sedimentary rocks.
If the baked and chilled margins at the lower part of the sill are fractured they allow hydrocarbons to migrate into the fractured reservoir. And if the upper margins are still intact the hydrocarbons are essentially trapped within the sill! Zoe also showed some theories about how the stress field of the regional tectonics influences sill emplacement and how it might be possible to predict if the margins are fractured or not.
On Tuesday I also attended my first ever PICO session. PICOs are interactive posters which can be a lot of fun and very educating or very hard to navigate and frustrating depending how well they are made. But it is a very good approach to bring the poster presentation into the 21st century!
First sessions on CO2 storage in the afternoon! Well on laboratory experiments and modelling CO2 storage but still exciting. But first on one of the best talks I have seen so far:
Debris flow fans record climate change
Debris flow fans (or alluvial fans) have always amazed me. When I visited the Death Valley National Park last year I got pretty excited about the sheer size of them (yep, still have to finish that blog post..) so I was very happy when I found a talk called “Debris ﬂow fans as sensitive recorders of glacial-interglacial climate change in the south-western United States” and I was not disappointed. Mitch D’Arcy from the Imperial College in London studied several debris flow fans just west of the Death Vally at the east side of the Sierra Nevada. He used cosmogenic nuclide data to constrain the ages of the flows (well actually he just used published data on them) and did some extensive grain size analysis in the field. He collected more than 30.000 (!!) grain sizes. And with grains I mean boulders and pebbles. Combining the grain sizes with the age data he was able to show that during glacials the grain sizes of the debris flows were actually smaller than during interglacials! This seems to be counter-intuitive as first: Why would the grain size be smaller during wetter and colder climate? The reasons for that are probably two: (1) During the ice ages glaciers in the mountains decreased the size of the drainage area that fed into the debris flows reducing the amount of water/rock that could flow. (2) During interglacials the average sea surface temperature at the coast of California was several degrees warmer (I think it was about 7C) which leads to a higher storm intensity. And big storms are the mechanism that brings rain into the rather dry area east of the Sierra Nevada.
Not only the science is pretty cool, but the way Mich presented his data was very clear as well! Once again I realized how important the style of presentation is…
Well cements and CO2 storage
One of the talks in the CCS session was on how cements along wells react to CO2 rich fluids. A big concern regarding CCS is that the cement of old wells might dissolve or at least get much more permeable if it reacts with CO2 rich fluids, leading to leakage of CO2 from the storage site along wells. Tim Wolterbeek from the University of Utrecht did some experiments and could show that even though the self-sealing capacity of cements is limited, the changes of permeability after two months of reaction are well within one order of magnitude. This is good news!
Dynamic imaging of fluid flow in sandstones
The way fluids move through a rock are still not very well understood. Often we do not have much more than data on how much and under what pressure fluids move into a piece of rock and on how long it takes to flow through it and how it might have changed during its travel. And we know the properties of the rock. But we do not have much of an idea of which way exactly the fluid takes within the rock! Ronny Pini from the Colorado School of Mines developed a new method that uses X-Ray CT combined with radioactive tracers, in his case 11C, that makes it possible to track the actual flow of a fluid/tracer through the rock. With this positron emission tomography he can understand the exact distribution of permeability in a rock sample, which in future will surely help to understand what is going on in a rock!
IPCC Report 2014: Findings and lessons learned
The last session I attended was about the findings of the latest IPCC report on Climate Change. Which sounded pretty interesting and I have been reading quite a lot of their reports during the last years so it was a great opportunity to see some of the lead authors in person! We arrived halfway through the session and heard the second half of Working Group 2 presentation on impacts, adaptation and vulnerability of climate change. The presenter was really good and made the points very clear. Sadly that was not true for the presentation on climate change mitigation. The presentation was all over the place and the presenter just read out the headings/text. From such an important scientist I had expected more and was quite disappointed. Only at the very end when he realized that he didn’t have an actual summary slide and he started to speak freely he delivered the key point: We need to act now!
The following discussion with the panel was business as usual but I really wished that the IPCC would take a more policy making role than just advising as I am afraid that without a well guided policy in the next few years we are going to steer towards 4C+ degrees of warming at the end of the century.
So much to day 2 and 3, day for was today and a summary will follow tomorrow!