May linkfest

The monthly News post wasn't one of our most popular features, so it's on the shelf. Instead, I thought I'd share all the most interesting, quirky, mind-blowing, or just plain cool things I've spotted on the web over the last month.

– Do not miss this. One of them stands out above all the others. If you like modern analogs and satellite imagery, you're going to love Google Earth Engine. I've started a list of geologically interesting places to visit — please add to it!

– More amazing images. I'll never get bored of looking at gigapans, and Callan Bentley's are among the best geological ones. I especially like his annotated ones.

– Classic blog. Greg Gbur writes one of the best physics blogs, and his focus is on optics, so there's often good stuff there for geophysicists. This post on Chladni patterns is pure acoustic goodness and well worth a slow read. 

– New geoscience blog. Darren Wilkinson is a young geoscientist in the UK, and writes a nice geeky blog about his research. 

– Brilliant and simple. Rowan Cockett is a student at UBC, but builds brilliant geological web apps on the side. He has a knack for simplicity and his latest creation makes stereonets seem, well, simple. Impressive. 

– New magazine. Kind of. There's not enough satire or ragging in the petroleum press, so it's refreshing to hear of Proved Plus Probable, a fairly wacky weekly online rag emanating from Calgary [thanks to Dan for the tip!]. Top headline: Legendary geologist invents new crayons. 

– Counter-factual geology. I love these pictures of an imagined ring around earth.

– Never buy graph paper again. Make some just how you like it!

– Bacon. It was a revelation to find that some rocks look just like bacon.

That's it! I share most of this sort of thing on Twitter. Really useful stuff I tend to stick on my pinboard — you're welcome to browse. If you have a geological or geeky bookmark collection, feel free to share it in the comments!

The deliberate search for innovation & excellence

Collaboration, knowledge sharing, and creativity — the soft skills — aren't important as ends in themselves. They're really about getting better at two things: excellence (your craft today) and innovation (your craft tomorrow). Soft skills matter not because they are means to those important ends, but because they are the only means to those ends. So it's worth getting better at them. Much better.

One small experiment

The Unsession three weeks ago was one small but deliberate experiment in our technical community's search for excellence and innovation. The idea was to get people out of one comfort zone — sitting in the dark sipping coffee and listening to a talk — and into another — animated discussion with a roomful of other subsurface enthusiasts. It worked: there was palpable energy in the room. People were talking and scribbling and arguing about geoscience. It was awesome. You should have been there. If you weren't, you can get a 3-minute hint of what you missed from the feature film...

Go on, share the movie — we want people to see what a great time we had! 

Big thank you to the award-winning Craig Hall Video & Photography (no relation :) of Canmore, Alberta, for putting this video together so professionally. Time lapse, smooth pans, talking heads, it has everything. We really loved working with them. Follow them on Twitter. 

Proceedings of an unsession

Two weeks ago today Evan and I hosted a different kind of session at the Canada GeoConvention. It was an experiment in collaboration and integration, and I'm happy to say it exceeded our expectations. We will definitely be doing it again, so if you were there, or even if you weren't, any and all feedback will help ensure the dial goes to 11.

One of the things we wanted from the session was evidence. Evidence of conversation, innovation, and creative thinking. We took home a great roll of paper and sticky notes, and have now captured it all in SubSurfWiki, along with notes from the event. You are invited to read and edit. Be bold! And please share the link...

  ageo.co/unsession

The video from the morning is in the editing suite right now: watch for that too.

We have started a write-up of the morning. If you came to the session, please consider yourself a co-author: your input and comments are welcome. You might be unaccustomed to editing a community document, but don't be shy — that's what it's there for. 

We want to share two aspects of the event on the blog. First, the planning and logistics of the session — a cheatsheet for when we (or you!) would like to repeat the experience. Second, the outcomes and insights from it — the actual content. Next time: planning an unsession.

Fitting a model to data

In studying the earth, we can't afford to take enough observations, and they will never be free of noise. So if you say you do geoscience, I hereby challenge you to formulate your work as a mathematical inverse problem. Inversion is a question: given the data, the physical equations, and details of the experiment, what is the distribution of physical properties? To answer this question we must address three more fundamental ones (Scales, Smith, and Treitel, 2001):

• How accurate is the data? Or what does fit mean?
• How accurately can we model the response of the system? Have we included all the physics that can contribute signifcantly to the data?
• What is known about the system independent of the data? There must be a systematic procedure for rejecting unreasonable models that fit the data as well.

Setting up an inverse problem means coming up with the equations that contain the physics and geometry of the system under study. The method for solving it depends on the nature of the system of equations. The simplest is the minimum norm solution, and you've heard of it before, but perhaps under a different name.

To fit is to optimize a system of equations

For problems where the number of observations is greater than the number of unknowns, we want to find which unknowns fit the best. One case you're already familiar with is the method of least squares — you've used it fitting a line of through a set of points. A line is unambiguously described by only two parameters: slope a and y-axis intercept b. These are the unknowns in the problem, they are the model m that we wish to solve for. The problem of line-fitting through a set of points can be written out like this,

As I described in a previous post, the system of the problem takes the form d = Gm, where each row links a data point to an equation of a line. The model vector m (M × 1), is smaller than the data d (N × 1) which makes it an over-determined problem, and G is a N × M matrix holding the equations of the system.

Why cast a system of equations in this matrix form? Well, it turns out that the the best-fit line is precisely,

which are trivial matrix operations, once you've written out G.  T means to take the transpose, and –1 means the inverse, the rest is matrix multiplication. Another name for this is the minimum norm solution, because it defines the model parameters (slope and intercept) for which the lengths (vector norm) between the data and the model are a minimum. 

One benefit that comes from estimating a best-fit model is that you get the goodness-of-fit for free. Which is convenient because making sense of the earth doesn't just mean coming up with models, but also expressing their uncertainty, in terms of the errors with which they are linked.

I submit to you that every problem in geology can be formulated as a mathematical inverse problem. The benefit of doing so is not just to do math for math's sake, but it is only through quantitatively portraying ambiguous inferences and parameterizing non-uniqueness that we can do better than interpreting or guessing. 

Reference (well worth reading!)

Scales, JA, Smith, ML, and Treitel, S (2001). Introductory Geophysical Inverse Theory. Golden, Colorado: Samizdat Press. 

Laying it all out at the Core Conference

Bobbing in the wake of the talks, the Core Conference turned out to be more exemplary of this year's theme, Integration. Best of all were SAGD case studies, where multi-disciplinary experiments are the only way to make sense of the sticky stuff.

Coring through steam

Travis Shackleton from Cenovus did a wonderful presentation showing the impact of bioturbation, facies boundaries, and sedimentary structures on steam chamber evolution in the McMurray Formation at the FCCL project. And because I had the chance to work on this project with ConocoPhillips a few years ago, but didn't, this work induced both jealousy and awe. Their experiment design is best framed as a series of questions:

• What if we drilled, logged, and instrumented two wells only 10 m apart? (Awesome.)
• What if we collected core in both of them? (Double awesome.)
• What if the wells were in the middle of a mature steam chamber? (Triple awesome.)
• What if we collected 3D seismic after injecting all this steam and compare with with a 3D from before? (Quadruple awesome.)

It is the first public display of SAGD-depleted oil sand, made available by an innovation of high-temperature core recovery. Travis pointed to a portion of core that had been rinsed by more than 5 years of steam circulating through it. It had a pale brown color and a residual oil saturation S_O of 15% (bottom sample in the figure). Then he pointed to a segment of core above the top of the steam chamber. It too was depleted, by essentially the same amount. You'd never know just by looking. It was sticky and black and largely unscathed. My eyes were fooled, direct observation deceived.

A bitumen core full of fractures

Jen-Russel-Houston held up a half-tube of core of high-density fractures riddled throughout bitumen saturated rock. The behemoth oil sands that require thermal recovery assistance have an equally promising but lesser known carbonate cousin, still in its infancy. It is the bitumen saturated Grosmont Formation, located to the west of the more mature in-situ projects in sand. The reservoir is entirely dolomite, hosting its own unique structures affecting the spreading of steam and the reduction of bitumen's viscosity to a flowable level.

Jen and her team at OSUM hope their pilot will demonstrate that these fractures serve as transport channels for the steam, allowing it to creep around tight spots in the reservoir, which would otherwise be block the steam in its tracks. These are not the same troubling baffles and barriers caused by mud plugs or IHS, but permeability heterogeneities caused by the dolomitization process. A big question is the effective permeability at the length scales of production, which is phenomenologically different to measurements made from cut core. I overheard a spectator suggest to Jen that she try to freeze a sleeve of core, soak it with acid then rinse the dolomite out the bottom. After which only a frozen sculpture of the bitumen would remain. Crazy? Maybe. Intriguing? Indeed. 

Let's do more science with rocks!

Two impressive experiments, unabashedly and literally laid out for all to see, equipped with clever geologists, and enriched by supplementary technology. Both are thoughtful initiatives—real scientific experiments—that not only make the operating companies more profitable, but also profoundly improve our understanding of a precious resource for society. Two role models for how comprehensive experiments can serve more than just those who conduct them. Integration at its very best, centered on core.

What are the best examples of integrated geoscience that you've seen?

Submitting assumptions for meaningful answers

The best talk of the conference was Ran Bachrach's on seismics for unconventionals. He enthusiastically described the physics to his spectators with conviction and duty, and explained why they should care. Isotropic, VTI, and orthorhombic media anisotropy models are used not because they are right, but because they are simple. If the assumptions you bring to the problem are reasonable, the answers can be considered meaningful. If you haven't considered and tested your assumptions, you haven't subscribed to reason. In a sense, you haven't held up your end of the bargain, and there will never be agreement. This talk should be mandatory viewing for anyone working seismic for unconventionals. Advocacy for reason. Too bad it wasn't recorded.

I am both privileged and obliged to celebrate such nuggets of awesomeness. That's a big reason why I blog. And on the contrary, we should call out crappy talks when we see them to raise the bar. Indeed, to quote Zen Faulkes, "...we should start creating more of an expectation that scientific talks will be reviewed and critiqued. And names will be named."

The talk from HEF Petrophysical entitled, Towards modelling three-dimensional oil sands permeability distribution using borehole image logs, drew me in. I was curious enough to show up. But as the talk unfolded, my curiosity was left unsatisfied. A potentially interesting workflow of transforming high-resolution resistivity measurements into flow permeability was obfuscated with a pointless upscaling step. The meat of anything like this is in the transform itself, but it was missing. It's also the most trivial bit; just cross-plot one property with another and show people. So I am guessing they didn't have any permeability data. If that was the case, how can you stand up and talk about permeability? It was a sandwich without the filling. The essential thing that defines a piece of work is the creativity. The thing you add that wasn't there before. I was disappointed. Disappointed that it was accepted, and that no one else piped up. 

I will paraphrase a conversation I had with Ran at the coffee break: Some are not aware, some choose to ignore, and some forget that works of geoscience are problems of extreme complexity. In fact, the only way we can cope with complexity is to make certain assumptions that make our problem solvable. If all you do is say "here is my solution", you suck. But if instead you ask, "Have I convinced you that my assumptions are reasonable?", it entirely changes the conversation. It entirely changes the specialist's role. Only when you understand your assumptions can we talk about whether the results are reasonable. 

Have you ever felt conflicted on whether or not you should say something?

A really good conversation

Today was Day 2 of the Canada GeoConvention. But... all we had the energy for was the famous Unsolved Problems Unsession. So no real highlights today, just a report from the floor of Room 101.

Today was the day. We slept about as well as two 8-year-olds on Christmas Eve, having been up half the night obsessively micro-hacking our meeting design (right). The nervous anticipation was richly rewarded. About 50 of the most creative, inquisitive, daring geoscientists at the GeoConvention came to the Unsession — mostly on purpose. Together, the group surfaced over 100 pressing questions facing the upstream industry, then filtered this list to 4 wide-reaching problems of integration:

• making the industry more open
• coping with error and uncertainty
• improving seismic resolution
• improving the way our industry is perceived

We owe a massive debt of thanks to our heroic hosts: Greg Bennett, Tannis McCartney, Chris Chalcraft, Adrian Smith, Charlene Radons, Cale White, Jenson Tan, and Tooney Fink. Every one of them far exceeded their brief and brought 100× more clarity and continuity to the conversations than we could have had without them. Seriously awesome people.  

This process of waking our industry up to new ways of collaborating is just beginning. We will, you can be certain, write more about the unsession after we've had a little time to parse and digest what happened.

If you're at the conference, tell us what we missed today!

A revolution in seismic acquisition?

We're in warm, sunny Calgary for the GeoConvention 2013. The conference feels like it's really embracing geophysics this year — in the past it's always felt more geological somehow. Even the exhibition floor felt dominated by geophysics. Someone we spoke to speculated that companies were holding their geological cards close to their chests, but the service companies are still happy to talk about (ahem, promote) their geophysical advances.

Are you at the conference? What do you think? Let us know in the comments.

We caught about 15 talks of the 100 or so on offer today. A few of them ignited the old whines about half-cocked proofs of efficacy. Why is it still acceptable to say that a particular seismic volume or inversion result is 'higher resolution' or 'more geological' with nothing more than a couple of sections or timeslices as evidence?

People are excited about designing seismic acquisition expressly for wavefield reconstruction. In a whole session devoted to the subject, for example, Mauricio Sacchi showed how randomization helps with regularization in processing, allowing us to either get better image quality, or to lower cost. It feels like the start of a new wave of innovation in acquisition, which has more than its fair share of recent innovation: multi-component, wide azimuth, dual-sensor, simultaneous source...

Is it a revolution? Or just the fallacy of new things looking revolutionary... until the next new thing? It's intriguing to the non-specialist. People are talking about 'beyond Nyquist' again, but this time without inducing howls of derision. We just spent an hour talking about it, and we think there's something deep going on... we're just not sure how to articulate it yet.

Unsolved problems

We were at the conference today, but really we are focused on the session we're hosting tomorrow morning. Along with a roomful of adventurous conference-goers (you're invited too!), looking for the most pressing questions in subsurface science. We start at 8 a.m. in Telus 101/102 on the main floor of the north building.

Here comes GeoConvention 2013

Next week Matt and I are heading to the petroleum capital of Canada for the 2013 GeoConvention. There will be 308 talks, 125 posters, over 4000 attendees, 100 exhibiting companies, and at least 2 guys blogging their highlights off.

My picks for Monday

Studying the technical abstracts ahead of time is the only way to make the most of your schedule. There are 9 sessions going on at any given time, a deep sense of FOMO has already set in. These are the talks I have decided on for Monday: 

Seismics for unconventionals

I watched Carl Reine from Nexen give a talk two years ago where he deduced a power-law relationship characterizing natural fracture networks in the Horn River shale. He will show how integrating such fracture intensity patterns with inversion models yields a powerful predictor of frackability, and uses microseismic to confirm it.

On a related note, and also from the Horn River Basin, Andreas Wuestefeld will show how microseismic can be used to identify fluid drainage patterns from microseismic data. Production simulation from an actual microseismic experiment. Numerical modeling, and physical experiment inextricably linked. I already love it.

Forward models and experimental tests

One is a design case study for optimizing interpolation, the other is a 3D seismic geometry experiment, the third is a benchtop physical fracture model made out of Plexiglass and resin.

Broadband seismic

Gets to the point of what hinders seismic resolution, and it does something about it through thoughtful design. This is just really nice looking data, two talks, same author: a step change, and impact of broadband. 

Best title award 

Goes to Forensic chemostratigraphy. Gimmicky name or revolutionary concept? You can't always judge a talk by the title, or the quality of the abstract. But it's hard not to. What talks are on your must-see list this year?

A really good conversation

Matt and I are hosting an unsession on the morning of Tuesday 7 May. It will be structured, interactive, and personal. The result: a ranked list of the most pressing problems facing the upstream geoscientists, especially in those hard to reach places between the disciplines. This is not a session where you sit and listen. Everyone will participate. We will explore questions that matter, connect diverse perspectives, and, above all, capture our collective knowledge. It might be scary, it might be uncomfortable, it might not be for you. But if you think it is, bring your experience and individuality, and we will do that thing called integration. We can only host 60 people, so if you don't want to be turned away, arrive early to claim a spot. We start at 8 a.m. in Telus 101/102 on the main floor of the north building.