April linkfest

It's time for our regular linkfest!

There's a new book in town... Rob Simm and Mike Bacon have put together a great-looking text on seismic amplitude intepretation (Cambridge, 2014). Mine hasn't arrived yet, so I can't say much more — for now, you can preview it in Google Books. I should add it to my list.

Staying with new literature, I started editing a new column in SEG's magazine The Leading Edge in February. I wrote about the first instalment, and now the second is out, courtesy of Leo Uieda — check out his tutorial on Euler deconvolution, complete with code. Next up is Evan with a look at synthetics.

On a related note, Matteo Niccoli just put up a great blog post on his awesome perceptual colourmaps, showing how to port them to matplotlib, the MATLAB-like plotting environment lots of people use with the Python programming language. 

Dolf Seilacher, the German ichnologist and palaeontologist, died 4 days ago at the age of 89. For me at least, his name is associated with the mysterious trace fossil Palaeodictyon — easily one of the weirdest things on earth (right). 

Geoscience mysteries just got a little easier to solve. As I mentioned the other day, there's a new place on the Internet for geoscientists to ask questions and help each other out. Stack Exchange, the epic Q&A site, has a new Earth Science site — check out this tricky question about hydrocarbon generation.

And finally, who would have thought that waiting 13 years for a drop of bitumen could be an anticlimax? But in the end, the long (if not eagerly) awaited 9th drop in the University of Queensland's epic experiment just didn't have far enough to fall...

If you can't get enough of this, you can wait for the 10th drop here. Or check back here in 2027.

A culture of asking questions

When I worked at ConocoPhillips, I was quite involved in their knowledge sharing efforts (and I still am). The most important part of the online component is a set of 100 or so open discussion forums. These are much like the ones you find all over the Internet (indeed, they're a big part of what made the Internet what it is — many of us remember Usenet, now Google Groups). But they're better because they're highly relevant, well moderated, and free of trolls. They are an important part of an 'asking' culture, which is an essential prerequisite for a learning organization. 

Stack Exchange is awesome

Today, the Q&A site I use most is Stack Overflow. I read something on it almost every day. This is the place to get questions about programming answered fast. It is one of over 100 sites at Stack Exchange, all excellent — readers might especially like the GIS Stack Exchange. These are not your normal forums... Fields medallist Tim Gowers recognizes Math Overflow as an important research tool. The guy has a blog. He is awesome.

What's so great about the Stack Exchange family? A few things:

• A simple system of up- and down-voting questions and answers that ensures good ones are easy to find.
• A transparent system of user reputation that reflects engagement and expertise, and is not easy to game. 
• A well defined path from proposal, to garnering support, to private testing, to public testing, to launch.
• Like good waiters, the moderators keep a very low profile. I rarely notice them. 
• There are lots of people there! This always helps.

The new site for earth science

The exciting news is that, two years after being proposed in Area 51, the Earth Science site has reached the minimum commitment, spent a week in beta, and is now open to all. What happens next is up to us — the community of geoscientists that want a well-run, well-populated place to ask and answer scientific questions.

You can sign in instantly with your Google or Facebook credentials. So go and take a look... Then take a deep breath and help someone. 

Private public data

Our recent trip to the AAPG Annual Convention in Houston was much enhanced by meeting some inspiring geoscientist–programmers. People like...

• Our old friend Jacob Foshee hung out with us and built his customary awesomeness.
• Wassim Benhallam, at the University of Utah, came to our Rock Hack and impressed everyone with his knowledge of clustering algorithms, and sedimentary geology.
• Sebastian Good, of Palladium Consulting, is full of beans and big ideas — and is a much more accomplished programmer than most of us will ever be. If you're coding geoscience, you'll like his blog.
• We had a laugh with Nick Thompson from Schlumberger, who we bumped into at a 100% geeky meet-up for Python programmers interested in web sockets. I cannot explain why we were there.

Perhaps the most animated person we met was Ted Kernan (right). A recent graduate of Colorado School of Mines, Ted has taught himself PHP, one of the most prevalent programming languages on the web (WordPress, Joomla, and MediaWiki are written in PHP). He's also up on all the important bits of web tech, like hosting, and HTML frameworks.

But the really cool thing is what he's built: a search utility for public well data in the United States. You can go and check it out at publicwelldata.com — and if you like it, let Ted know!

Actually, that's not even the really cool thing. The really cool thing is how passionate he is about exposing this important public resource, and making it discoverable and accessible. He highlights the stark difference between Colorado's easy access to digital well data, complete with well logs, and the sorry state of affairs in North Dakota, where he can't even get his app in to read well names. 'Public data' can no longer mean "we'll sell you a paper printout for $40". It belongs on the web — machines can read too.

More than just wells

There's so much potential power here — not only for human geoscientists looking for well data, but also for geoscientist–programmers building tools that need well data. For example, I imagine being able to point modelr.io at any public well to grab its curves and make a quick synthetic. Ready access to open services like Ted's will free subsurface software from the deadweight of corporate databases filled with years of junk, and make us all a bit more nimble. 

We'll be discussing open data, and openness in general, at the Openness Unsession in Calgary on the afternoon of 12 May — part of GeoConvention 2014. Join us!

Can openness make us better? Help us find out!

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!

More AAPG highlights

Here are some of our highlights from the second half of the AAPG Annual Convention in Houston.

Conceptual uncertainty in interpretation

Fold-thrust belt, offshore Nigeria. Virtual Seismic Atlas.Rob Butler's research is concerned with the kinematic evolution of mountain ranges and fold thrust belts in order to understand the localization of deformation across many scales. Patterns of deformed rocks aren't adequately explained by stress fields alone; they are also controlled by the mechancial properties of the layers themselves. Given this fact, the definition of the layers becomes a doubly important part of the interpretation.

The biggest risk in structural interpretation is not geometrical accuracy but whether or not the concept is correct. This is not to say that we don't understand geologic processes. Rather, a section can always be described in more than one way. It is this risk in the first order model that impacts everything we do. To deal with conceptual uncertainty we must first capture the range, otherwise it is useless to do any more refinement. 

He showed a crowd-sourced compiliation of 24 interpretations from the Virtual Seismic Atlas as a way to stack up a series of possible structural frameworks. Fifteen out of twenty-four interviewees interpreted a continuous, forward-propagating thrust fault as the main structure. The disagreements were around the existence and location of a back thrust, linkage between fore- and back-thrusts, the existence and location of a detachment surface, and its linkage to the fault planes above. Given such complexity, "it's rather daft," he said, "to get an interpretation from only one or two people." 

CT scanning gravity flows

Mike Tilston and Bill Arnott gave a pair of talks about their research into sediment gravity flows in the lab. This wouldn't be newsworthy in itself, but their 2 key innovations caught our attention: 

1. A 3D velocity profiler capable of making 23 measurements a second
2. The flume tank ran through a CT scanner, giving a hi-res cross-section view

These two methods sidestep the two major problems with even low-density (say 4% by weight) sediment gravity flows: they are acoustically attenuative, and optically opaque. Using this approach Tilston and Arnott investigated the effect of grain size on the internal grain distribution, finding that fine-grained turbidity currents sustain a plug-like wall of sediment, while coarse-grained flows have a more carpet-like distribution. Next, they plan to look at particle shape effects, finer grain sizes, and grain mixtures. Technology for the win!

Hypothesizing a martian ocean

Lorena Moscardelli showed topograhic renderings of the Eberswalde delta (right) on the planet Mars, hypothesizing that some martian sedimentary rocks have been deposited by fluvial processes. An assertion that posits the red planet with a watery past. If there are sedimentary rocks formed by fluids, one of the fluids could have been water. If there has been water, who knows what else? Hydrocarbons? Imagine that! Her talk was in the afternoon session on Space and Energy Frontiers, sandwiched by less scientific speakers raising issues for staking claims and models for governing mineral and energy resources away from earth. The idea of tweaking earthly policies and state regulations to manage resources on other planets, somehow doesn't align with my vision of an advanced civilization. But the idea of doing seismic on other planets? So cool.

Poster gorgeousness

Matt and I were both invigorated by the quality, not to mention the giant size, of the posters at the back of the exhibition hall. It was a place for the hardcore geoscientists to retreat from the bright lights, uniformed sales reps, and the my-carpet-is-cushier-than-your-carpet marketing festival. An oasis of authentic geoscience and applied research.

We both finally got to meet Brian Romans, a sedimentologist at Virginia Tech, amidst the poster-paneled walls. He said that this is his 10th year venturing to the channel deposits that crop out in the Magallanes Basin of southern Chile. He is now one of the three young, energetic profs behind the hugely popular Chile Slope Systems consortium.

Three years ago he joined forces with Lisa Stright (University of Utah), and Steve Hubbard (University of Calgary) and formed the project investigating processes of sediment transfer across deepwater slopes exposed around Patagonia. It is a powerhouse of collaborative research, and the quality of graduate student work being pumped out is fantastic. Purposeful and intentional investigations carried out by passionate and tech-savvy scientists. What can be more exciting than that?

Do you have any highlights of your own? Please leave a note in the comments.

Communicating geoscience

On Day 1 of the AAPG Annual Convention, I spent most of the morning in a special session entitled Communicating Our Science. I thought I'd share some of my thoughts on the subject. Please share yours in the comments!

This was primarily a panel discussion, but the convenors took several of questions from the audience of about 40 people. If the room had been smaller, and the audio system better-behaved, we might have had more of a conversation.

The panel consisted of three academics, two journalists, and a political lobbyist. While most of the panel had some direct experience in industry, there was a conspicuous and slightly mystifying absence of anyone currently working in industry. There was a less surprising but possibly more troubling absence of anyone representing 'the public' (whoever they are). The panelists were:

• Jim Reilly, Dean of Science and Technology Development, American Public University System
• Michael Zehr, Federal Policy Advisory, Consumer Energy Alliance
• Heather Saucier, Correspondent, AAPG Explorer magazine
• Jane Whaley, Editor in Chief, GeoExPro Magazine
• Donald Paul, Professor of Engineering, Chair of Energy Resources, USC
• Iain Stewart, Professor of Geosciences Communication, University of Plymouth

Questions covered topics like "Where can I get information about energy issues?" (the EIA is a good start) to "How should I answer emotional questions about fracking?"(Honestly... and send people to Frack-Land). Most of the answers focused on engaging with the public, or with the press. But I'm most interested in how our own community communicates with itself, so the question I wanted to ask (I wasn't chosen by the chairs) was this:

The panel advises industry to engage with the public and communicate with authenticity and transparency, and I agree completely. But my perception is that we don't model this type of communication when we talk to each other, never mind the public — companies are wary of sharing methods and data, and we're most comfortable with controlled, one-way communication like talks, papers, and panel discussions. Does the panel agree, and if so, does it have any recommendations for improving how our technical community talks to itself? 

I do love the concept of sessions like this — we absolutely need more of them. But I think we need to think more about the purpose, and what we can get out of them. For example, no-one was capturing the proceedings, as far as I could tell (and a video would certainly be the wrong way to do that here). And there was no way to circle back to the crowd for a reflection on the panel's responses. We can do better.

That said, there were plenty of nuggets of wisdom from the panel. One of my favourites was a remark from Iain Stewart: "I don't think we should be focusing on increasing the public's scientific literacy, we should be focusing on building trust." At the very end, the panel were asked for advice for AAPG and the professional community:

• AAPG should build a repository of links, blogs, and FAQs about geoscience — Jim Reilly
• We need more data to support our reporting and outreach — Michael Zehr
• Technical societies should offer writing courses and seminars — Heather Saucier (here's one :)
• Industry has to be more proactive with public engagement — Jane Whaley
• Public engagement is not an option anymore, it's a core skill — Donald Paul
• Communicators should embrace the human side of science with enthusiasm — Iain Stewart

I could get behind all of those. What about you?

Dynamic geology at AAPG

Brad Moorman stands next to his 48 inch (122 cm) Omni Globe spherical projection system on the AAPG exhibition floor, greeting passers by drawn in by its cycling animations of Getech's dynamic plate reconstructions. His map-lamp projects evolutionary visions of geologic processes like a beacon of inspiration for petroleum explorers.

I've attended several themed sessions over the first day and a half at AAPG and the ones that have stood out for me have had this same appeal.

Computational stratigraphy

Processes such as accommodation rate and sedimentation rate can be difficult to unpeel from stratal geometries. Guy Prince's PhD Impact of non-uniqueness on sequence stratigraphy used a variety of input parameters and did numerical computations to make key stratigraphic surfaces with striking similarity. By forward modeling the depositional dynamics, he showed that there are at least two ways to make a maximum flooding surface, a sequence boundary, and top set aggradations. Non-uniqueness implies that there isn't just one model that fits the data, nor two, however Guy cleverly made simple comparisons to illustrate such ambiguities. The next step in this methodology, and it is a big step, is to express the entire model space: just how many solutions are there? 

If you were a farmer here, you lost your land

Henry Posamentier, seismic geomorphologist at Chevron, showed extremely high-resolution 3D sparker seismic imaging just beneath the seafloor in the Gulf of Thailand. Because this locale is more than 1000 km from the nearest continental shelf, it has been essentially unaffected by sea-level change, making it an ideal place to study pure fluvial depositional patterns. Such fluvial systems result in reservoirs in their accretionary point bars, but they are hard to predict.

To make his point, Henry showed a satellite image of the Ping River from a few years ago in the north of Chiang Mai, where meander loops had shifted sporadically in response to one flood season: "If you were a farmer here, you lost your land."

Wells can tell about channel thickness, and seismic may resolve the channel width and the sinuosity, but only a dynamic model of the environment can suggest how well-connected is the sand.

The evolution of a single meandering channel belt

Ron Boyd from ConocoPhillips showed a four-step process investigating the evolution of a single channel belt in his talk, Tidal-Fluvial Sedimentology and Stratigraphy of the McMurray Formation.

1. Start with a cartoon facies interpretation of channel evolution.
2. Trace out the static geomorphological model on seismic time slices.
3. Identify directions of fluvial migrations point by point, time step by time step.
4. Distribute petrophysical properties within each channel element in chronological sequence.

Mapping the dynamics of a geologic scenario along a timeline gives you access to all the pieces of a single geologic puzzle. But what really matters is how that puzzle compares with the handful of pieces in your hand.

More tomorrow — stay tuned.

Google Earth imagery ©2014 DigitalGlobe, maps ©2014 Google

This post was modified on April 16, 2014, mentioning and giving redirects to Getech.

Hacking logs

Over the weekend, 6 intrepid geologist-geeks gathered in a coworking space in the East Downtown area of Houston. With only six people, I wasn't sure we could generate the same kind of creative buzz we had at the geophysics hackathon last September. But sitting with other geoscientists and solving problems with code works at any scale. 

The theme of the event was 'Doing cool things with log data'. There were no formal teams and no judging round. Nonetheless, some paired up in loose alliances, according to their interests. Here's a taste of what we got done in 2 days...

Multi-scale display

Jacob Foshee and Ben Bougher worked on some JavaScript to display logs with the sort of adaptive scrolling feature you often see on finance sites for displaying time series. The challenge was to display not just one log with its zoomed version, but multiple logs at multiple scales — and ideally core photos too. They got the multiple logs, though not yet at multiple scales, and they got the core photo. The example (right) shows some real logs from Panuke, a real core photo from the McMurray, and a fake synthetic seismogram. 

Click on the image for a demo. And the code is all open, all the way. Thanks guys for an awesome effort!

Multi-scale log attributes

Evan and Mark Dahl (ConocoPhillips) — who was new to Python on Friday — built some fascinating displays (right). The idea was to explore stratigraphic stacking patterns in scale space. It's a little like spectral decomposition for 1D data. They averaged a log at a range of window sizes, increasing exponentially (musicians and geophysicists know that scale is best thought of in octaves). Then they made a display that ranges from short windows on the left-hand side to long ones on the right. Once you get your head around what exactly you're looking at here, you naturally want to ask questions about what these gothic-window patterns mean geologically (if anything), and what we can do with them. Can we use them to help train a facies classifier, for example? [Get Evan's code]

Facies from logs

In between running for tacos, I worked on computing grey-level co-occurence matrices (GLCMs) for logs, which are a prerequisite for computing certain texture attributes. Why would anyone do this? We'd often like to predict facies from well logs; maybe log textures (spiky vs flat, upwards-fining vs barrel-shaped) can help us discriminate facies better. [Download my IPython Notebook]

Wassim Benhallam (of Lisa Stright's Rocks to Models lab at University of Utah) worked on machine learning algorithms for computing facies from core. He started pursuing self-organizing maps as an interesting line of attack, and plans to use MATLAB to get something working. I hope he tells us how it goes!

We didn't have a formal contest at this event, but our friend Maitri Erwin was kind enough to stop by with some excellent wine and her characteristically insightful and inquisitive demeanour. After two days rattling around with nothing but geeks and tacos for company, she provided some much-needed objectivity and gave us all good ideas about how to develop our efforts in the coming weeks. 

We'll be doing this again in Denver this autumn, some time around the SEG Annual Meeting. If it appeals to your creativity — maybe there's a tool you've always wished for — why not plan to join us?  

As I get around to it, I'll be dumping more info and pictures over on the wiki. 

Looking forward to AAPG

Today we're en route to the AAPG Annual Convention & Exhibition (the ACE) in Houston. We have various things going on before it and after it too, so we're in Houston for 10 days of geoscience. Epic!

The appetizers

On Friday we're hosting a 'learning geoscience programming' bootcamp at START, our favourite Houston coworking space. Then we roll straight into our weekend programming workshop — Rock Hack — also at START. Everyone is welcome — programming newbies, established hackers. We want to build tools for working with well logs. You don't need any special skills, just ideas. Bring whatever you have! We'll be there from 8 am on Saturday. (Want more info?)

At least come for the breakfast tacos.

Conference highlight forecast

Regular readers will know that I'm a bit of a jaded conference-goer. But I haven't been to AAPG since Calgary in 2005, and I am committed to reporting the latest in geoscience goodness — so I promise to go to some talks and report back on this very blog. I'm really looking forward to it since Brian Romans whet my appetite with a round-up of his group's research offerings last week. 

I thought I'd share what else I'll be trying to get to. I can't find a way to link to the abstracts — you'll have to hunt them down in the Itinerary Planner... 

• Monday am. Communicating our science. Jim Reilly, Iain Stewart, and others.
• Monday pm. Case Studies of Geological and Geophysical Integration sounds okay, but might under-deliver. And there's a talk called 3-D Printing Artificial Reservoir Rocks to Test Their Petrophysical Properties, by Sergey Ishutov that should be worth checking out.
• Tuesday am.  Petroleum Geochemistry and Source Rock Characterization, in honour of Wally Dow
• Tuesday pm. Turbidites and Contourites, Room 360, is the place to be. Zane Jobe is your host.
• Wednesday am. I'll probably end up in Seismic Visualization of Hydrocarbon Play Fairways.
• Wednesday pm. Who can resist Space and Energy Frontiers? Not me.

That's about it. I'm teaching my geoscience writing course at a client's offices on Friday, then heading home. Evan will be hanging out and hacking some more I expect. Expect some updates to modelr.io!

If you're reading this, and you will be at AAPG — look out for us! We'll be the ones sitting on the floor near electrical outlets, frantically typing blog posts.

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Getting started with Modelr

Let's take a closer look at modelr.io, our new modeling tool. Just like real seismic experiments, there are four components:

• Make a framework. Define the geometries of rock layers.
• Make an earth. Assign a set of rock properties to each layer.
• Make a kernel. Define the seismic survey.
• Make a plot. Set the output parameters.

Modelr takes care of the physics of wave propagation and reflection, so you don't have to stick with normal incidence acoustic impedance models if you don't want to. You can explore the full range of possibilities.

3 ways to slice a wedge

To the uninitiated, the classic 3-layer wedge model may seem ridiculously trivial. Surely the earth looks more complicated than that! But we can leverage such geometric simplicity to systematically study how seismic waveforms change across spatial and non-spatial dimensions. 

Spatial domain. In cross-section (right), a seismic wedge model lets you analyse the resolving power of a given wavelet. In this display the onset of tuning is marked by the vertical red line, and the thickness at which maximum tuning occurs is shown in blue. Reflection profiles can be shown for any incidence angle, or range of incidence angles (offset stack).

Amplitude versus angle (AVA) domain. Maybe you are working on a seismic inversion problem so you might want to see what a CDP angle gather looks like above and below tuning thickness. Will a tuned AVA response change your quantitative analysis? This 3-layer model looks like a two-layer AVA gather except our original wavelet looks like it has undergone a 90 degree phase rotation. Looks can be deceiving. 

Amplitude versus frequency domain. If you are trying to design a seismic source for your next survey, and you want to ensure you've got sufficient bandwidth to resolve a thin bed, you can compute a frequency gather — right, bottom — and explore a swath of wavelets with regard to critical thickness in your prospect. The tuning frequency (blue) and resolving frequency (red) are revealed in this domain as well. 

Wedges are tools for seismic waveform classification. We aren't just interested in digitizing peaks and troughs, but the subtle interplay of amplitude tuning, and apparent phase rotation variations across the range of angles and bandwidths in the seismic experiment. We need to know what we can expect from the data, from our supposed geology. 

In a nutshell, all seismic models are about illustrating the band-limited nature of seismic data on specific geologic scenarios. They help us calibrate our intuition when bandwidth causes ambiguity in interpretation. Which is nearly all of the time.