Fibre optic seismology at #GeoCon14

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We've been so busy this week, it's hard to take time to write. But for the record, here are two talks I liked yesterday at the Canada GeoConvention. Short version — Geophysics is awesome!

DAS good

Todd Bown from OptaSense gave an overview of the emerging applications for distributed acoustic sensing (DAS) technology. DAS works by shining laser pulses down a fibre optic cable, and measuring the amount of backscatter from impurities in the cable. Tiny variations in strain on the cable induced by a passing seismic wave, say, are detected as subtle time delays between light pulses. Amazing.

Fibre optic cables aren't as sensitive as standard geophone systems (yet?), but compared to conventional instrumentation, DAS systems have several advantages:

  • Deployment is easy: fibre is strapped to the outside of casing, and left in place for years.
  • You don't have to re-enter and interupt well operations to collect data.
  • You can build ultra-long receiver arrays — as long as your spool of fibre.
  • They are sensitive to a very broad band of signals, from DC to kilohertz.

Strain fronts

Later in the same session, Paul Webster (Shell) showed results from an experiment that used DAS as a fracture diagnosis tool. That means you can record for minutes, hours, even days; if you can cope with all that data. Shell has accumulated over 300 TB of records from a handful of projects, and seems to be a leader in this area.

By placing a cable in one horizontal well in order to listen to the frac treatment from another, the cable can effectively designed to record data similar to a conventional shot gather, except with a time axis of 30 minutes. On the gathers he drew attention to slow-moving arcuate events that he called strain fronts. He hypothesized a number of mechanisms that might cause these curious signals: the flood of fracking fluids finding their way into the wellbore, the settling and closing creep of rock around proppant, and so on. This work is novel and important because it offers insight into the mechanical behavoir of engineered reservoirs, not just during the treatment, but long after.

Why is geophysics awesome? We can measure sound with light. A mile underground. That's all.

Looking forward to #GeoCon14

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Agile is off to Calgary on Sunday. We have three things on our List of Thing To Do: 

  1. We're hosting another Unsession on Monday... If you're in Calgary, please come along! It's just like any other session at the conference, only a bit more awesome.
  2. We'll be blogging from GeoConvention 2014. If there's a talk you'd like to send us to, we take requests! Just drop us a line or tweet at us!
  3. Evan is teaching his Creative Geocomputing class. Interested? There are still places. A transformative experience, or your money back.

What's hot at GeoCon14

Here's a run-down of what we're looking forward to catching:

  • Monday: Maybe it's just me, but I always find seismic acquisition talks stimulating. In the afternoon, the Unsession is the place to be. Not Marco Perez's probably awesome talk about brittleness and stress. Definitely not. 
  • Tuesday: If it wasn't for the fear of thrombosis, it'd be tempting to go to Glen 206 and stay in Log Analysis sessions all day. In the afternoon, the conference is trying something new and interesting — Jen Russel-Houston (a bright spark if ever there was one) is hosting a PechaKucha — lightning versions of the best of GeoConvention 2013. 
  • Wednesday: This year's conference is unusually promising, because there is yet another session being given over to 'something different' — two actually. A career-focused track will run all day in Macleod D, called (slightly weirdly) ‘On Belay’: FOCUSing on the Climb that is a Career in Geoscience. Outside of that, I'd head for the Core Analysis sessions.
  • Friday: We won't be there this year, but the Core Conference is always worth going to. I haven't been to anything like it at any other conference. It's open on Thursday too, but go on the Friday for the barbeque (tix required).

The GeoConvention is always a good conference. It surprises me how few geoscientists come from outside of Canada to this event. Adventurous geophysicists especially should consider trying it one year — Calgary is really the epicentre of seismic geophysics, and perhaps of petrophysics too.

And the ski hills are still open.

Can openness make us better? Help us find out!

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Last year's Unsolved Problems Unsession (above) identified two openness issues — Less secrecy, more sharing and Free the data — as the greatest unsolved problems in our community. This year, we'll dig into that problem. Here's the blurb:

At the Unsolved Problems Unsession last year, this community established that Too much secrecy is one of the top unsolved problems in our industry. This year, we will dig into this problem, and ask what kind of opportunities solving it could create. What forces cause closedness to persist? What are the advantages of being more open? Where is change happening today? Where can we effect change next?

We offer no agenda, no experts, no talks, and no answers. This is an open space for everyone to come and be their best and brightest self. So bring it.

GeoConvention Monday 12 May, afternoon in Telus 108 (ground floor on the north side)

No experts? No answers? What on earth are we up to? Well, we think bringing questions to a group of engaged professionals is more fun than bringing answers. The idea is to talk about our greatest aspirations for our discipline, and how we can find out if greater transparency and openness can help us achieve them.

If you know someone else who would enjoy this, please tell them about it or bring them along. I hope we see you there on 12 May!