News
Thursday
Nov082012

Brittleness and robovibes

Day 3 of the SEG Annual Meeting was just as rammed with geophysics as the previous two days. I missed this morning's technical program, however, as I've taken on the chairpersonship (if that's a word) of the SEG Online Committee. So I had fun today getting to grips with that business. Aside: if you have opinion's about SEG's online presence, please feel free to send them my way.

Here are my highlights from the rest of the day — both were footnotes in their respective talks:

Brittleness — Lev Vernick, Marathon

Evan and I have had a What is brittleness? post in our Drafts folder for almost two years. We're skeptical of the prevailing view that a shale's brittleness is (a) a tangible rock property and (b) a function of Young's modulus and Poisson's ratio, as proposed by Rickman et al. 2008, SPE 115258. To hear such an intellect as Lev declare the same today convinced me that we need to finish that post — stay tuned for that. Bottom line: computing shale brittleness from elastic properties is not physically meaningful. We need to find more appropriate measures of frackability, which Lev pointed out is, generally speaking, inversely proportional to organic content. This poses a basic conflict for those exploiting shale plays. 

Robovibes — Guus Berkhout, TU Delft

At least 75% of Berkhout's talk went by me today, mostly over my head. I stopped writing notes, which I only do when I'm defeated. But once he'd got his blended source stuff out of the way, he went rogue and asked the following questions:

  1. Why do we combine all seismic frequencies into the device? Audio got over this years ago (right).
  2. Why do we put all the frequencies at the same location? Viz 7.1 surround sound.
  3. Why don't we try more crazy things in acquisition?

I've wondered the same thing myself — thinking more about the receiver side than the sources — after hearing about the brilliant sampling strategy the Square Kilometer Array is using at a PIMS Lunchbox Lecture once. But Berkhout didn't stop at just spreading a few low-frequency vibrators around the place. No, he wants robots. He wants an autonomous army of flying and/or floating narrow-band sources, each on its own grid, each with its own ghost matching, each with its own deblending code. This might be the cheapest million-channel acquisition system possible. Berkhout's aeronautical vibrator project starts in January. Seriously.

More posts from SEG 2012. 

Speaker image is licensed CC-BY-SA by Tobias Rütten, Wikipedia user Metoc.

Tuesday
Nov062012

Smoothing, unsmoothness, and stuff

Day 2 at the SEG Annual Meeting in Las Vegas continued with 191 talks and dozens more posters. People are rushing around all over the place — there are absolutely no breaks, other than lunch, so it's easy to get frazzled. Here are my highlights:

Adam Halpert, Stanford

Image segmentation is an important class of problems in computer vision. An application to seismic data is to automatically pick a contiguous cloud of voxels from the 3D seismic image — a salt body, perhaps. Before trying to do this, it is common to reduce noise (e.g. roughness and jitter) by smoothing the image. The trick is to do this without blurring geologically important edges. Halpert did the hard work and assessed a number of smoothers for both efficacy and efficiency: median (easy), Kuwahara, maximum homogeneity median, Hale's bilateral [PDF], and AlBinHassan's filter. You can read all about his research in his paper online [PDF]. 

Dave Hale, Colorado School of Mines

Automatic fault detection is a long-standing problem in interpretation. Methods tend to focus on optimizing a dissimilarity image of some kind (e.g. Bø 2012 and Dorn 2012), or on detecting planar discontinuities in that image. Hale's method is, I think, a new approach. And it seems to work well, finding fault planes and their throw (right).

Fear not, it's not complete automation — the method can't organize fault planes, interpret their meaning, or discriminate artifacts. But it is undoubtedly faster, more accurate, and more objective than a human. His test dataset is the F3 dataset from dGB's Open Seismic Repository. The shallow section, which resembles the famous polygonally faulted Eocene of the North Sea and elsewhere, contains point-up conical faults that no human would have picked. He is open to explanations of this geometry. 

Other good bits

John Etgen and Chandan Kumar of BP made a very useful tutorial poster about the differences and similarities between pre-stack time and depth migration. They busted some myths about PreSTM:

  • Time migration is actually not always more amplitude-friendly than depth migration.
  • Time migration does not necessarily produce less noisy images.
  • Time migration does not necessarily produce higher frequency images.
  • Time migration is not necessarily less sensitive to velocity errors.
  • Time migration images do not necessarily have time units.
  • Time migrations can use the wave equation.
  • But time migration is definitely less expensive than depth migration. That's not a myth.

Brian Frehner of Oklahoma State presented his research [PDF] to the Historical Preservation Committee, which I happened to be in this morning. Check out his interesting-looking book, Finding Oil: The Nature of Petroleum Geology

Jon Claerbout of Stanford gave his first talk in several years. I missed it unfortunately, but Sergey Fomel said it was his highlight of the day, and that's good enough for me. Jon is a big proponent of openness in geophysics, so no surprise that he put his talk on YouTube days ago:

The image from Hale is copyright of SEG, from the 2012 Annual Meeting proceedings, and used here in accordance with their permissions guidelines. The DOI links in this post don't work at the time of writing — SEG is on it. 

Tuesday
Nov062012

Resolution, anisotropy, and brains

Day 1 of the SEG Annual Meeting continued with the start of the regular program — 96 talks and 71 posters, not to mention the 323 booths on the exhibition floor. Instead of deciding where to start, I wandered around the bookstore and bought Don Herron's nice-looking new book, First Steps in Seismic Interpretation, which we will review some time soon.

Here are my highlights from the rest of the day.

Chuck Ursenbach, Arcis

Calgary is the home of seismic geophysics. There's a deep tradition of signal processing, and getting the basics right. Sometimes there's snake oil too, but mostly it's good, honest science. And mathematics. So when Jim Gaiser suggested last year at SEG that PS data might offer as good resolution as SS or PP — as good, and possibly better — you know someone in Calgary will jump on it with MATLAB. Ursenbach, Cary, and Perz [PDF] did some jumping, and conclude: PP-to-PS mapping can indeed increase bandwidth, but the resolution is unchanged, because the wavelength is unchanged — 'conservation of resolution', as Ursenbach put it. Resolution isn't everything. 

Gabriel Chao, Total E&P

Chao showed a real-world case study starting with a PreSTM gather with a decent Class 2p AVO anomaly at the top of the reservoir interval (TTI Kirchhoff with 450–4350 m offset). There was residual NMO in the gather, as Leon Thomsen himself later forced Chao to admit, but there did seem to be a phase reversal at about 25°. The authors compared the gather with three synthetics: isotropic convolutional, anisotropic convolutional, and full waveform. The isotropic model was fair, but the phase reversal was out at 33°. The anisotropic convolutional model matched well right up to about 42°, beyond which only the full waveform model was close (right). Anisotropy made a similar difference to wavelet extraction, especially beyond about 25°.

Canada prevails

With no hockey to divert them, Canadians are focusing on geophysical contests this year. With the Canadian champions Keneth Silva and Abdolnaser Yousetz Zadeh denied the chance to go for the world title by circumstances beyond their control, Canada fielded a scratch team of Adrian Smith (U of C) and Darragh O'Connor (Dalhousie). So much depth is there in the boreal Americas that the pair stormed home with the trophy, the cash, and the glory.

The Challenge Bowl event was a delight — live music, semi-raucous cheering, and who can resist MC Peter Duncan's cheesy jests? If you weren't there, promise yourself you'll go next year. 

The image from Chao is copyright of SEG, from the 2012 Annual Meeting proceedings, and used here in accordance with their permissions guidelines. The image of Herron's book is also copyright of SEG; its use here is proposed to be fair use.

Monday
Nov052012

The tepidity of social responsibility

Like last year, the 2012 SEG Forum was the only organized event on the morning of Day 1. And like last year, it was thinly attended. The title wasn't exactly enticing — Corporate and Academic Social Responsibility: Engagement or Estrangement — and to be honest I had no idea what we were in for. This stuff borders on sociology, and there's plenty of unfamiliar jargon. Some highlights:  

  • Part of our responsibility to society is professional excellence — Isabelle Lambert
  • At least one company now speaks of a 'privilege', not 'license', to operate — Isabelle Lambert
  • Over-regulation is harmful, but we need them to promote disclosure and transparency — Steve Silliman
  • The cheapest, easiest way to look like you care is to actually care

What they said

Mary Lou Zoback of Stanford moderated graciously throughout, despite being clearly perturbed by the thin audience. Jonathan Nyquist of Temple University was first up, and told how he is trying to get things done with $77k/year grad students using $50k grants when most donors want results not research.

Isabelle Lambert of CGGVeritas (above) eloquently described the company's principles. They actually seem to walk the walk: they were the only corporation to reply to the invitation to this forum, they seem very self-aware and open on the issue, and they have a policy of 'no political donations' — something that undermines a lot of what certain companies say about the environment, according to one questioner. 

Steve Silliman of Gonzaga University, a hydrologist, stressed the importance of the long-term view. One of his most successful projects has taken 14 years to reach its most impactful work, and has required funding from a wide range of sources — he had a terrific display of exactly when and how all this funding came in. 

Finally Michael Oxman, of Business for Social Responsibility, highlighted some interesting questions about stakeholder engagement, such as 'What constitues informed consultation?', and 'What constritutes consent?'. He was on the jargony end of things, so I got a bit lost after that.

What do you think, is social responsibility part of the culture where you work? Should it be? 

A footnote about the forum

"Social responsibility has become a popular topic these days", proclaimed the program. Not that popular, it turned out, with less than 2% of delegates showing up. Perhaps this is just the wrong venue for this particular conversation — Oxman pointed out that there is plenty of engagement in more specific venues. But maybe there's another reason for the dearth — this expert-centric, presentation-driven format felt dated somehow. Important people on stage, the unwashed, unnamed masses asking questions at the end. There was a nod to modernity: you could submit questions via Twitter or email, as well as on cards. But is this format, this approach to engagement, dead?

There's nothing to lose: let's declare it dead right now and promise ourselves that the opening morning of SEG in 2013 will be something to get our teeth into.

Thursday
Nov012012

Ways to experiment with conferences

Yesterday I wrote about why I think technical conferences underdeliver. Coincidentally, Evan sent me this quote from Seth Godin's blog yesterday:

We've all been offered access to so many tools, so many valuable connections, so many committed people. What an opportunity.

What should we do about it? 

If we are collectively spending 6 careers at the SEG Annual Meeting every autumn, as I asserted yesterday, let's put some of that cognitive surplus to work!

I suggest starting to experiment with our conferences. There are so many tools: unconferences, idea jams, hackdays, wikithons, and other participative activities. Anything to break up sitting in the dark watching 16 lectures a day, slamming coffee and cramming posters in between. Anything to get people not just talking and drinking, but working together. What a way to build collaborations, friendships, and trust. Connecting with humans, not business cards. 

Unconvinced? consider which of these groups of people looks like they're learning, being productive, and having fun:

This year I've been to some random (for me) conferences — Science Online, Wikimania, and Strata. Here are some engaging, fun, and inspiring things happening in meetings of those communities:

  • Speaker 'office hours' during the breaks so you can find them and ask questions. 
  • Self-selected topical discussion tables at lunch. 
  • Actual time for actual discussion after talks (no, really!).
  • Cool giveaways: tattoos and stickers, funky notebooks, useful mobile apps, books, scientific toys.
  • A chance to sit down and work with others — hackathons, co-writing, idea jams, and so on. 
  • Engaged, relevant, grounded social media presence, not more marketing.
  • An art gallery, including graphics captured during sessions
  • No posters! Those things epitomize the churn of one-way communication.

Come to our experiment!

Clearly there's no shortage of things to try. Converting a session here, a workshop there — it's easy to do something in a sandbox, alongside the traditional. And by 'easy', I mean uncertain, risky and uncomfortable. It will require a new kind of openness. I'm not certain of the outcome, but I am certain that it's worth doing. 

On this note, a wonderful thing happened to us recently. We were — and still are — planning an unconference of our own (stay tuned for that). Then, quite unprovoked, Carmen Dumitrescu asked Evan if we'd like to chair a session at the Canada GeoConvention in May. And she invited us to 'do something different'. Perfect timing!

So — mark your calendar! GeoConvention, Calgary, May 2013. Something different.

The photo of the lecture, from the depressing point of view of the speaker, is licensed CC-BY-SA by Flickr user Pierre-Alain Dorange. The one of the unconference is licensed CC-BY-SA-NC by Flickr user aforgrave.