This is just the beginning. The exploration industry needs to transition as quickly as possible to working with the wavefield. Coming later this week is the site where we will explain how we will do it.
It is time somebody did because our most modern way of communicating seismic information is still the gray scale display. Developed in 1983 and remaining fundamentally unaltered ever since, gray scale displays miss out on 30 years of critical research into the principles of visual communication and the technological improvements now available to visualize seismic in its natural state: as an analog acoustic wavefield.
The purpose of The Visual Wavefield Project is to take decades of unimplemented science and technology and apply it to the critically important task of visually clarifying the seismic image and the wealth of information it contains.
Everything we do is focussed around seismic being an analog wavefield. We develop graphic techniques to visually reconstruct it and we develop theoretical approaches to visualize it. These are two very complex tasks and they are each based upon a totally different set of sciences and technologies.
It is based upon our solid understanding of what seismic is and the process that go into acquiring and processing it.
It is based upon our in depth knowledge of the human visual processing system and how we communicate information through it.
Two very disparate sciences. But put them together and …
Despite all of the mathematical processes that we use to process seismic, eventually all of the information we produce must be communicated visually to the interpreter or the processor. Our ability to make critical, sometimes >100 million dollar decisions, rest almost entirely upon our ability to “see” what is in the data.
But what does “seeing” really mean?
Humans, as primates, are different than all other mammals. Their brains are dominated by their olfactory sense and they live in a world of scent and odour.
Our brain, however, is dominated by our Visual Cortex. Vision is our primary sensory modality and our visual processing system is so adept at producing visual percepts (internal representations of external objects) that we never we never give it, or the percepts it produces, a second’s thought.
We notice auditory percepts (sounds) as being something in the world around us but visual percepts, the objects we “see”, are the world around us.
We developed gray scale displays in the early 80’s. Since then we have learned much about how our visual processing system takes individual photons striking the retina and turns them into things that are real. We have learned that the process of perception is not automatic and that for our visual processing system to do its work it must be supplied with the right kind of information.
Without doubt, the most startling result of our visualization research is that conventional seismic displays do not supply it. They travel through our Visual Cortex without comment and as a result, seismic interpretation is a strictly cognitive process. We use our eyes and our higher brain functions but we never use our visual processing system.
When you think about how much time you spend looking at seismic, the idea that you have never actually “seen” it probably comes as a bit of a surprise. It won’t be the last.
Gray Scale Displays are our go-to display for any sort of structural interpretation and our best chance for directly detecting faults on vertical seismic sections. We developed them in 1983 to address the problems we had with variable density displays. They were the best we could do at the time.
But if seismic were invented today, would they be the best we could do today or would we, with our detailed knowledge of visualization principles, come up with something else entirely?
There are two independent neural circuits in the human visual cortex. The first (and the original) is the achromatic circuit, which process luminance (black and white) information. The second is the chromatic circuit, which processes color contrast information. The two circuits exist in parallel but when it comes to perception, they are definitely not equal.
Our perception of the shape and form of an object comes almost entirely from how our primary achromatic circuit interprets how the object reflects light. Color does not come into it at this point.
On first glance, gray scale displays may appear to be so purely achromatic that they would produce full perceptions, but this is not the case. They are fed through our achromatic circuit but since they linearly map amplitude to shade our visual cortex still can’t make sense of them. It has evolved to interpret reflectance and reflectance is anything but linear.
Gray scale displays can produce very weak percepts but nothing like the rich detail and sensation that emerges from treating seismic as what it really is, a three-dimensional surface.
We developed variable density displays in 1978 only to display instantaneous seismic attributes. Interpreters refused to use them for seismic until they were forced to when we started interpreting on computer monitors. They are purely chromatic and we use them today anytime amplitude is important.
There is just one small problem with them …
Humans may be visual creatures but that doesn’t mean we have good color vision. We may have better color perceptions than other mammals but our ability to discriminate color variations does not come close to that of birds, reptiles or even Devonian Fish.
We don’t even “see” color directly. The colors you are looking at now never exist as color coded signals anywhere in the visual cortex. We only interpret color by contrast, those interpretations being degraded by our losing two of the original four color receptor genes during our long dark Cretaceous night.
Variable Density Displays mean even less because they are processed entirely by our secondary chromatic neural circuit and they cannot, therefore, produce perceptions at all.
Both theoretically and practically, variable density displays are the most ineffective communication medium for complex data sets possible. They especially cannot communicate even a fraction of the complex and overwhelming amount of amplitude information in even the simplest of seismic sections.
Wiggle trace displays are our go-to display for any type of Stratigraphic Interpretation. They are our only way of examining character and waveform and they are currently our best way of visualizing things like terminations and unconformities. They date back to the 1960’s so we have to ask: “if seismic were invented today, would invent them?”
Probably not because wavefield displays can fulfill almost all of the roles wiggle traces do now only better. So we probably would not reinvent wiggle traces, which would be a pity because we may not “see” colors …
You not have to go too far into the visual system to realize that it is, at its most fundamental level, a pattern recognition engine and that it is very good at detecting lines.
That is probably a good thing for an arboreal species, which is what we were when we developed most of our visual capabilities.
It is also very good for geoscientists, because it is why we love wiggle traces so much and why, despite all their limitations, wiggle traces still have a place in the future of stratigraphic interpretation.
Because of their obvious and considerable advantages, Wavefield Displays will replace wiggle trace displays for the bulk of stratigraphic analysis but because of the unique perspective wiggle traces provide, they will never replace them entirely.
And I, for one, am quite pleased with that.
That said, nothing in history has given such a false first impression as has seismic. If there is one thing to take away from the comparisons we have shown you it must be that seismic is not the dull and dispassionate fractured images that we have grown used to. Seismic is alive and vibrant and we are decades away from learning its true potential.
Seismic is an analog acoustic wavefield and if seismic were invented today, in this world of multi-teraflop graphic cards, reconstructing and visualizing that wavefield would be as automatic as are deconvolution and migration. But seismic was not invented today. It was invented in technological antiquity, decades before we had the science and technology to visualize it correctly. As a result, our perception of what it is and what it is capable of is wrong.
We have to unlearn what we see now as its limitations and become re-enthused about its potential to unlock the secrets of the subsurface. We need to go back to the beginning and study it all over again.
In other words …
Dr. Lynch is the founder and Chief Geoscientist for The Visual Wavefield Project. He received his B.Sc. in Biophysics (with Distinction) from the University of Guelph in 1975 and his M.Sc. in Geophysics from the University of British Columbia in 1977.
Following a 26 year absence from academia, Steve returned to University in 2003 to study seismic visualization and received his Ph.D. from the University of Calgary in 2008.
Steve has a wide range of experience in both geophysical research and software development and has managed both seismic processing centers and research departments.
Working as an independent researcher, he has also developed techniques for such varied subjects as refraction statics, depth migration, ray trace structural modeling and stratigraphic modeling.
Because Dr. Lynch began his career in biophysics, before transitioning his efforts to geophysics, his origins offer him a unique perspective on the interaction between humans and the seismic they attempt to interpret. Dissatisfied with historical visualization techniques, Dr. Lynch has spent the last 15 years developing new and innovative methods of visually communicating seismic information.
These efforts have materialized into The Visual Wavefield Project with its focus on understanding, explaining and developing methods for seismic visualization that are vastly more in tune with how human brains process visual information.
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