Curvelets, dreamlets, and a few tears

Day 3 of the SEG Annual Meeting came and went in a bit of a blur. Delegates were palpably close to saturation, getting harder to impress. Most were no longer taking notes, happy to let the geophysical tide of acoustic signal, and occasional noise, wash over them. Here's what we saw.

Gilles Hennenfent, Chevron

I (Evan) loved Gilles's talk Interpretive noise attenuation in the curvelet domain. For someone who is merely a spectator in the arena of domain transforms and noise removal techniques, I was surprised to find it digestable and well-paced. Coherent noise can be difficult to remove independently from coherent signal, but using dyadic partitions of the frequency-wavenumber (f-k) domain, sectors called curvelets can be muted or amplified for reducing noise and increasing signal. Curvelets have popped up in a few talks, because they can be a very sparse representation of seismic data.

Speaking of exotic signal decompositions, Ru-Shan Wu, University of California at Santa Clara, took his audience to new heights, or depths, or widths, or... something. Halfway through his description of the seismic wavefield as a light-cone in 4D Fourier time-space best characterized by drumbeat beamlets—or dreamlets—we realized that we'd fallen through a wormhole in the seismic continuum and stopped taking notes.

Lev Vernik, Marathon

Lev dished a delicious spread of tidbits crucial for understanding the geomechanical control on hydraulic fracture stimulations. It's common practice to drill parallel to the minimum horizontal stress direction to optimize fracture growth away from the well location. For isotropic linear elastic fracture behaviour, the breakdown pressure of a formation is a function of the maximum horizontal stress, the vertical stress, the pore pressure, and the fracture toughness. Unfortunately, rocks we'd like to frack are not isotropic, and need to be understood in terms of anisotropy and inelastic strains.

Lastly, we stopped in to look at the posters. But instead of being the fun-fest of awesome geoscience we were looking forward to (we're optimistic people), it was a bit of a downer and made us rather sad. Posters are often a bit unsatisfactory for the presenter: they are difficult to make, and often tucked away in a seldom-visited corner of the conference. But there was no less-frequented corner of San Antonio, and possibly the state of Texas, than the dingy poster hall at SEG this year. There were perhaps 25 people looking at the 400-or-so posters. Like us, most of them were crying.

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Randomness and thin beds

Day 2 of the SEG Annual Meeting brought another 93 talks in the morning, and 103 in the afternoon, leaving us bewildered again: how to choose ten or so talks to see? (We have some ideas on this, more of which another day). Matt tried just sitting through a single session (well, almost), whereas Evan adopted the migrant approach again. These are our picks, just for you.

Stewart Trickett, Kelman

There has never been a dull or difficult talk from Stewart, one of Calgary's smartest and most thoughtful programmer–processors. He has recently addressed the hot-topic of 5D interpolation, a powerful process for making the dream of cheap, dense sampling a reality. Today, he explained why we need to now think about optimizing acquisition not for imaging, but for interpolation. And interpolation really likes pseudorandom sampling, because it helps negotiate the terms & conditions of Nyquist and avoid spatial aliasing. He went on to show a 3D subsampled then imaged three ways: remove every other shot line, remove every other shot, or remove a random shot from every pair of shots. All reduce the fold to 12% of the full data. The result: pseudorandom sampling wins every time. But don't panic, the difference in the migrated images was much smaller than in the structure stacks.

Gaynor Payton, ffA

In what could have been a product-focused marketing talk, Gaynor did a good job of outlining five easy-to-follow, practical workflows for interpreters working on thin beds. She showed frequency- and phase-based methods that exploit near-tuning, unresolved doublets in the waveform. A nice-looking bandwidth enhancement result was followed up with ffA's new high-resolution spectral decomposition we covered recently. Then she showed how negative spikes in instantaneous frequency can reveal subtle doublets in the waveform. This was extended with a skeletonized image, a sort of band-limited reflectivity display. Finally, she showed an interesting display of signed trace slope, which seemed to reveal the extent of just-resolved doublets quite nicely.

Scott Mackay, consultant

Scott MacKay shared some of his deep experience with depth imaging, but specially translated for interpreters. And this is only right: depth imaging is first and foremost an interpretive, iterative process, not a product. He gave some basic heuristics, guiding principles for interpreters. The first velocity model should be smooth—really smooth. Iterations should be only incrementally less smooth, 'creeping up' on the solution. Structure should get less, not more, complex with each step. Gathers should be flattish, not flat. Be patient, and let the data speak. And above all, Don't Panic. Always good advice.

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Diffractions, Dust, and sub-Hertz imaging

Even the keenest geophysicist (and we are the keenest geophysicists) had to miss 96 presentations today. The first afternoon of talks comprised an impressive 104 talks in 13 sessions. If only 10% of talks are great, you might see one, and you would miss at least nine. Fortunately there are two of us, so we double our chances. These are our highlights.

Will Burnett, UT Austin

Diffractions, usually thought of as noise, emanate predominantly from faults and discontinuities. Will wants not to eliminate them but to use them as a complementary signal to boost imaging. His talk on diffraction velocity analysis described how, instead of picking an exact velocity model, a range of velocities are used to compute independent test images of diffraction events. Because the apex of a diffraction is the same no matter what velocity is applied, a stack of test images results in a concentration of the diffractor at the apex; the remaining events are stacked out. Blending this image with a reflection processed seismic yields a more vivid image. Also, this work was done using Madagascar... yay, open source!

Kris Pister, Dust Networks

The power of mobile devices is impressive, but Dust Networks can build an accelerometer with optical communication and a microcontroller in a 5 mm³ box. The autonomous sensors build a time-synchronized mesh protocol with channel-hopping (yeah, they do!), meaning you end up with an internet-like network that tolerates dead nodes and other failures. Now Dust build such networks of all kinds of sensors, of all sizes, in industrial applications, and surely will soon be appearing in a wellbore or seismic array near you. One to watch.

Rebecca Saltzer, ExxonMobil

Easily the most enthusiastic presentation of the day was a rip-roaring tale from Wyoming. ExxonMobil buried fifty-five low-frequency Guralp CMG3T seismometers at their LaBarge oil and gas field. The devices were arranged in a line pointing towards the Pacific, to ensure a good source of earthquakes: the source for this grand experiment. The P-waves they intended to image with have a dominant frequency of about 1 Hz, hence the seismometers, with their 0.08 to 50 Hz bandwidth. And image they did: the result was a velocity model with 500 m vertical resolution and good agreement with a 1000-well velocity model.

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Frontiers at the Forum

The SEG Forum was the main attraction on Day 1 of the SEG Annual Meeting in San Antonio. Several people commented that the turnout was rather poor, however, with no more than 400 people sitting in the Lila Cockrell Theatre, even at the start. Perhaps the event needs more publicity. There was plenty of time for questions from the audience, all of which the panel discussed quite candidly.

David Lawrence, Executive VP of Exploration and Commercial at Shell gave, predictably, a rather dry corporate presentation. We understand how presentations like this get hijacked by lawyers and corporate communications departments, but wish more executives would stand up to their captors, especially for a short presentation to a technical audience. Despite his shackles, he had some eyebrow-raising technology to brag about: futuristic autonomous-vehicle marine nodes, and a million-channel sensor network, a project development they're developing with HP, of all companies.

Tim Dodson, Executive VP of Exploration at Statoil and once Matt's boss there, seemed similarly held captive by his corporation's presentation sanitizers. Saved by his charisma, Tim characterized Statoil's steady approach in exploration: deep pockets, patience, and being comfortable with risk. They seem to have the same approach to technology innovation, as Tim highlighted their Source Rock from Seismic method for characterizing source rocks and the high-resolution spectral decomposition technology we wrote about recently. Both projects took several years to develop, and have paid off in discoveries like Aldous and Skrugard respectively.

Susan Cunningham, Senior VP of Exploration at Noble Energy, spoke about her company's approach to frontier exploration. Despite her chronic use of buzz-phrases (innovative thinking, integrated objective assessment, partner of choice), Susan gave a spirited outlook on the human angles of Noble's frontier thinking. She discussed Noble's perseverance in the Eastern Mediterranean 8.5 Tcf Tamar discovery in the Levant Basin, and went on to describe Noble as a large company in a small company framework, but we're not sure what that means. Is it good?

Carl Trowell, president of WesternGeco and the youngest panelist, was the most engaging (and convincing) speaker. Shell's corporate communications people need to see presentations like this one: more powerful and trustable for its candid, personal, style. As you'd expect, he had deep insight into where seismic technolology is going. He lamented that seismic is not used enough in risk mitigation for frontier wells; for example, borehole seismic-while-drilling, imaged in the time it takes to trip out of the hole, can help predict pore pressure and other hazards in near-real-time. His forward-looking, energetic style was refreshing and inspiring.

It was a slightly dry, but basically up-beat, kick-off to the meeting. Some high-altitude perspective before we helicopter down to the nitty-gritty of the talks this afternoon.

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Broken ice

Click for the latest newsUntil today, I was an SEG virgin; I can now see what all the fuss is about.

The SEG Annual Meeting is big. Massive. And it feels important, or at least significant. It is clear that exploration geophysics lives here. Every step takes you past something cool... there's FairfieldNodal's seismic node exhibit, and here's Transform Software's stained-glass-window spectral display. And every other step is like flicking through an issue of Geophysics... there's Sergey Fomel, here's Öz Yilmaz. Although I know only a few people here, I have a stong feeling of familiarity and belonging. I like it. No: I love it.

I taught my writing course this morning. It was the smallest course in the world, with a grand total of three students of the written word. Fortunately, they turned out to be wonderful company, and taught me at least twice as much as I taught them. We spent much of the morning talking about new directions in science writing, openness in industry and academia, and the competition for attention. The SEG showed considerable faith in me and my subject matter in offering this course, because it has faltered before over the years. But clearly something needs to change if we agree to offer it again... It seems that honing soft skills is not what people are looking for. Perhaps a course like mine is better suited to online consumption in bite-size webcasts. Or maybe I just needed more elliptic partial differential equations.

What do you think of courses like this? Too fluffy? Too long? Too boring?

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Follow the SEG conference

The eighty-first annual meeting of the Society of Exploration Geophysicists (SEG) will be held in San Antonio next week. The technical session will hold over 600 oral poster presentations, and the exposition hall will be hosted by more than 350 companies, government agencies, research and educational institutions. More than 8000 people from 85 countries will attend.

Whether you are roaming on-site, or stuck in your office, find out what people are saying, what's happening, and get involved in the conversation. You can follow live updates throughout the week by coming back to this post or searching for the hashtag #SEG11 using Twitter's search.

If you are going to the conference, consider sharing your ideas and engaging with this community. Or tell us what you think by leaving a comment.

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