Field Report from Utah

Having just returned home after a couple of weeks of fieldwork in Utah, USA, it seemed appropriate to stick up a wee post about what I got up to out there. The aim of the fieldwork was two-fold:

  1. Primarily to collect water samples from ten CO2-driven geysers/springs in the San Rafael desert area to the south of Green River, Utah
  2. Collect rock samples from the Navajo sandstone formation, wherever it was easily accessible/available at outcrop

If you’ve read Part 1 of my introduction to my PhD (Part 2 to follow soon!), then you’ll probably be wondering why I’m in Utah when my PhD focus is the UK North Sea.  The reason why I’m sampling rocks and geysers in the USA is that they are a natural analogue for potential industrial CO2 storage.  The geysers in Utah which I have been sampling are, unusually, cold water.  This means that instead of being geothermally driven by the heat of igneous (molten rock) activity, like Old Faithful in Yellowstone, or the Rotorua geysers in the North Island of New Zealand, they are driven by CO2. So water which is saturated with CO2 migrates to the surface in each geyser from sandstones which would be analogous to a North Sea storage sites.  There will have been natural CO2-water-rock interactions, and given the surface expression of these ‘reacted’ waters, it makes them relatively cheap and easy to sample; perfect for a PhD!  The chemistry of these waters, particularly their trace element contents, can then be compared with what might be expected – based on lab experiments – for North Sea CO2-water-rock interactions.  It is this comparison which is the overall aim of the fieldwork, and that data will appear at a later date, hopefully published in a peer-reviewed journal. I had arranged a collaboration with the Bureau of Economic Geology (BEG) at the University of Texas (UT), Austin and am very grateful for the assistance of Jiemin Lu, Pat Mickler and Staci Lowey at BEG.  They have been complete stars, arranging for sampling kits to be prepared and shipped to me at Green River as well as arranging and carrying out the analysis I needed (and more!).  The samples are currently with UT and as I write this I’m awaiting the results. The kits which were sent from BEG allowed me, with a fellow PhD student from the University of Edinburgh, to collect water samples from the geysers for analysis of major and trace cations, anions, dissolved inorganic carbon (DIC), carbon, hydrogen and oxygen istopes, and alkalinity.  The sampling involved some hand-breaking work filtering of the geyser water samples into several bottles and vials to return back to Austin. Below is a gallery of a photo each of the geysers which we sampled from, in no particular order, with their co-ords in [Lat., Long.].  There’s a Google map at the bottom of this post with the geyser locations (careful of entering private land – check with the Sheriff’s Office in Green River). Notice how varied they are! Some I don’t think even qualify for ‘geyser’, such as the “Side Seep” location. One significant thing we found, having gone out fairly blind with respect to what we expected to find at each location, was that some bubbled away constantly, whereas others were intermittent. The intermittent locations obviously gave us some problems with sampling, since we did not know how fresh any standing water was surrounding the geyser outflow. Under the gallery is a short (around 3.5 minutes) video of phone-recorded clips of eight of the geysers. Unfortunately neither of us got any video of the 10 Mile and Pseudo 10 Mile geysers, which is annoying but too late to do anything about it now. Geyser photo gallery:

Geyser video: The rock samples – a secondary objective – were taken from a large road cutting through the western extent of the San Rafael Swell, where I-70 climbs up from the San Rafael desert up onto the swell. The exact locations are not particularly important, but I collected about 3 samples over a 1km transect heading west through the section shown in the photo immediately below, sampling Entrada (before the cutting), Navajo and Wingate sandstones. Rock sampling photo gallery:

Geyser location map:

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6 thoughts on “Field Report from Utah

  1. Great photos! You’ve captured some interesting landscapes and geology there.

    Am I right to think that when we talk of storing CO2 in rock formations deep underground, the process of doing this is largely similar to what mining companies do when they refer to fracking? Except that in the case of fracking, they’re injecting water into the rock rather than CO2. I was also wondering why the North Sea is currently being investigated as the place to store CO2? Why not somewhere on land?

    • The only real similarity with fracking is that it involves drilling a hole (or holes) into a subsurface geological formation. Fracking uses fluid pressure to fracture the target rock, to allow trapped natural gas to escape, which is then produced at the wellhead. CO2, however, is injected into the target rock with the aim of *not* fracturing, as we’re trying to ensure that the CO2 stays there! You might be thinking of Enhanced Oil Recovery (EOR) which can be (and is) done with CO2, where carbon dioxide is injected into an oil reservoir to increase the amount of oil that can be extracted. Some CO2 remains after the oil is produced, so this can be used to store CO2 as well as produce oil.

      Storage in the UK will be offshore because 1) that’s where the big suitable rock formations are; and 2) no/less public acceptance issues to deal with for onshore storage (“Not under my backyard etc”).

      • Ok, thanks. I gathered that in the case of CO2 storage, the idea is not to fracture the rock. But the depth and rock formations, are they similar for both? I realise too that there are political differences between the two with sequestering CO2 seeking to solve the problem caused, in part, by fracking.

        I forgot about the NIMBYs. I should have thought of that.

    • Ah, I see what you mean. Yes, similar depth range, but different rocks. In fracking i.e. shale gas extraction, the target rocks are shale/mudstones (very fine grained, extremely low permeability). In CO2 storage, the target rocks are (mostly) sandstones, which are coarser grained and with low to high permeabilities. In this case, because CO2 is buoyant in water, it will rise to the top of the formation if it doesn’t dissolve/react and so typically CO2 storage sites require a shale/mudstone as a ‘cap’ or seal above the sandstone because gas essentially can’t pass through.

  2. Really cool images of the geysers! That I70 road cut looks very familiar 😀
    @Rachel: The mechanisms of storing CO2 in the subsurface and the recovery of unconventional gas (also called fracking) are very different! But I let Kit explain that 🙂

  3. Pingback: What’s my PhD all about? (Part 2) | Vitamin CCS

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