Unsolved problems in applied geoscience

I like unsolved problems. I first wrote about them way back in late 2010 — Unsolved problems was the eleventh post on this blog. I touched on the theme again in 2013, before and after the first 'unsession' at the GeoConvention, which itself was dedicated to finding the most pressing questions in exploration geoscience. As we turn towards the unsession at AAPG in Salt Lake City in May, I find myself thinking again about unsolved problems. Specifically, what are they? How can we find them? And what can we do to make them easier to solve?

It turns out lots of people have asked these questions before.

I've compiled a list of various attempts by geoscientists to list he big questions in the field. The only one I was previous aware of was Milo Backus's challenges in applied seismic geophysics, laid out in his president's column in GEOPHYSICS in 1980 and highlighted later by Larry Lines as part of the SEG's 75th anniversary. Here are some notable attempts:

• John William Dawson, 1883 — Nova Scotia's most famous geologist listed unsolved problems in geology in his presidential address to the American Association for the Advancement of Science. They included the Cambrian Explosion, and the origin of the Antarctic icecap. 
• Leason Heberling Adams, 1947 — One of the first experimental rock physicists, Adams made the first list I can find in geophysics, which was less than 30 years old at the time. He included the origin of the geomagnetic field, and the temperature of the earth's interior.
• Milo Backus, 1980 — The list included direct hydrocarbon detection, seismic imaging, attenuation, and anisotropy.  
• Mary Lou Zoback, 2000 — As her presidential address to the GSA, Zoback kept things quite high-level, asking questions about finding signal indynamic systems, defining mass flux and energy balance, identifying feedback loops, and communicating uncertainty and risk. This last one pops up in almost every list since.
• Calgary's geoscience community, 2013 — The 2013 unsession unearthed a list of questions from about 50 geoscientists. They included: open data, improving seismic resolution, dealing with error and uncertainty, and global water management.
• Daniel Garcia-Castellanos, 2014 — The Retos Terrícolas blog listed 49 problems in 7 categories, ranging from the early solar system to the earth's interior, plate tectonics, oceans, and climate. The list is still maintained by Daniel and pops up occasionally on other blogs and on Wikipedia.

The list continues — you can see them all in this presentation I made for a talk (online) at the Bureau of Economic Geology last week (thank you to Sergey Fomel for hosting me!). During the talk, I took the opportunity to ask those present what their unsolved problems are, especially the ones in their own fields. Here are a few of what we got (the rest are in the preso):

What are your unsolved problems in applied geoscience? Share them in the comments!

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If you have about 50 minutes to spare, you can watch the talk here, courtesy of BEG's streaming service.

Click here to watch the talk >>>

Free the (seismic) data!

Yesterday afternoon Evan and I hosted the second unsession at the GeoConvention in Calgary. After last year exposing 'Free the data' as one of the unsolved problems in subsurface geoscience, we elected to explore this idea further. And we're addicted to this kind of guided, recorded conversation.

Attendance was a little thin, but those who came spent the afternoon deep in conversation about open data, open software, and greater industry transparency. And we unearthed an exciting and potentially epic conclusion that I hope leads to a small revolution.

What happened?

Rather than leaving the floor completely open, we again brought some structure to the proceedings. I'll post the full version to the wiki page, but here's the overview:

1. Group seismic interpretation: 5 interpreters in 5 minutes.
2. Stories about openness: which of 26 short stories resonate with you most?
3. Open/closed, accessible/inaccessible: a scorecard for petroleum geoscience.
4. Where are the opportunities? What should we move from closed to open?

As you might expect, the last part was the real point. We wanted to find some high-value areas to poke, or at least gather evidence around. And one area—one data type—was identified as being (a) closed and inaccessible in Canada and (b) much more impactful if it were open and accessible. I gave the punchline away in the title, but that data type is seismic data.

Open, public seismic data is much too juicy a topic to do justice to in this post, so stay tuned for a review of some the specifics of how that conversation went. Meanwhile, imagine a world with free, public seismic data...

Reflections on the 2nd edition

The afternoon went well, and the outcome was intriguing, but we were definitely disappointed by the turnout. We have multiple working hypotheses about it...

• There may not be a strong appetite for this sort of session, especially on a 'soft' topic. Next time: seismic resolution?
• The first day might not be the best time for it, because people are still in the mood for talks. Next time: Wednesday morning?
• The programme maybe didn't reflect what the unsession was about, and the time was unclear. Next time: More visibility.
• Three hours may be too much to ask from people, though you could say the same about any other session here.

We'd love to hear your thoughts too... Are we barking up completely the wrong tree? Does our community even want to have these conversations? Should we try again in 2015?

Grand challenges, anisotropy, and diffractions

Some more highlights from the two final days of the SEG Annual Meeting in Houston.

Grand challenges

On Friday, I reported on Chevron's take on the unsolved problems in petroleum geoscience. It was largely about technology. Ken Tubman, VP of Geoscience and Reservoir Engineering at ConocoPhillips gave an equally compelling outlook on some different issue. He had five points:

• Protect the base — Fighting the decline of current production is more challenging than growing production.
• Deepwater — Recent advances in drilling are providing access to larger fields in deep water, and compressed sampling in seismic will make exploration more efficient.
• Unconventionals — In regard to the shale gas frenzy, it is not yet obvious why these reservoirs produce the way that they do. Also, since resource plays are so massive, a big challenge will be shooting larger surveys on land.
• Environment and safety — Containment assurance is more critical than pay-zone management, and geophysics will find an expanding role in preventing and diagnosing environmental and safety issues.
• People — Corporations are concerned about maintaining world class people. Which will only become more difficult as the demographic bump of senior knowledge heads off into retirement.

The Calgary crowd that harvested the list of unsolved problems at our unsession in May touched on many of these points, and identified many others that went unmentioned in this session.

Driving anisotropic ideas

In the past, seismic imaging and wave propagation were almost exclusively driven by isotropic ideas. In the final talk of the technical program, Leon Thomsen asserted that the industry has been doing AVO wrong for 30 years, and doing geomechanics wrong for 5 years. Three take-aways:

• Isotropy is no longer an acceptable approximation. It is conceptually flawed to relate Young's modulus (an elastic property), to brittleness (a mode of failure). 
• Abolish the terms vertically transverse isotropy (VTI), and horizontally transverse isotropy (HTI) from our vocabulary; how confusing to have types of anisotropy with isotropy in the name! Use polar anisotropy (for VTI), and azimuthal anisotropy (for HTI) instead.
• λ₁₃ is a simple expression of P-wave modulus M, and Thomsen's polar anisotropy parameter δ, so it should be attainable with logs.

Bill Goodway, whose work with elasticity has been criticized by Thomsen, walked to the microphone and pointed out to both the speaker and audience, that the tractability of λ₁₃ is what he has been saying all along. Colin Sayers then stood up to reiterate that geomechanics is the statistics of extremes. Anisotropic rock physics is uncontestable, but the challenge remains to find correlations with things we actually measure.

Thomas Young's sketch of 2-slit diffraction, which he showed to the Royal Society in 1803.

Imaging fractures using diffractions

Diffractions are fascinating physical phenomena that occur when the conditions of wave propagation change dramatically. They are a sort of grey zone between reflection and scattering, and can be used to resolve fractures in the subsufrace. The question is whether or not there is enough diffraction energy to detect the fractures; it can be 10× smaller than a specular reflection, so one needs very good data acquisition. Problem is, we must subtract reflections — which we deliberately optimized for — from the wavefield to get diffractions. Evgeny Landa, from Opera Geophysical, was terse, 'we must first study noise, in this case the noise is the reflections... We must study the enemy before we kill it.'

Prospecting with plate tectonics

The Santos, Campos, and Espirito Basins off the coast of Brazil contain prolific oil discoveries and, through the application of plate tectonics, explorers have been able to extend the play concepts to offshore western Africa. John Dribus, Geological Advisor at Schlumberger, described a number of discoveries as 'kissing cousins' on either side of the Atlantic, using fundamental concepts of continental margin systems and plate tectonics (read more here). He spoke passionately about big ideas, and acknowledged collaboration as a necessity: 'if we don't share our knowledge we re-invent the wheel, and we can't do that any longer'.

In the discussion session afterwards, I asked him to comment on offshore successes, which has historically hovered around 14–18%. He noted that a step change — up to about 35% — in success occured in 2009, and he gave 3 causes for it: 

• Seismic imaging around 2005 started dealing with anisotropy appropriately, getting the images right.
• Improved understanding of maturation and petroleum system elements that we didn’t have before.
• Access to places we didn’t have access to before.

Although the workshop format isn't all that different from the relentless PowerPoint of the technical talks, it did have an entirely different feeling. Was it the ample discussion time, or the fact that the trade show, now packed neatly in plywood boxes, boosted the signal:noise? Did you see anything remarkable at a workshop last week?