Forward modeling of seismic data is the most important workflow that nobody does.
Why is it important?
- Communicate with your team. You know your seismic has a peak frequency of 22 Hz and your target is 15–50 m thick. Modeling can help illustrate the likely resolution limits of your data, and how much better it would be with twice the bandwidth, or half the noise.
- Calibrate your attributes. Sure, the wells are wet, but what if they had gas in that thick sand? You can predict the effects of changing the lithology, or thickness, or porosity, or anything else, on your seismic data.
- Calibrate your intuition. Only by predicting the seismic reponse of the geology you think you're dealing with, and comparing this with the response you actually get, can you start to get a feel for what you're really interpreting. Viz Bruce Hart's great review paper we mentioned last year (right).
Why does nobody do it?
Well, not 'nobody'. Most interpreters make 1D forward models — synthetic seismograms — as part of the well tie workflow. Model gathers are common in AVO analysis. But it's very unusual to see other 2D models, and I'm not sure I've ever seen a 3D model outside of an academic environment. Why is this, when there's so much to be gained? I don't know, but I think it has something to do with software.
- Subsurface software is niche. So vendors are looking at a small group of users for almost any workflow, let alone one that nobody does. So the market isn't very competitive.
- Modeling workflows aren't rocket surgery, but they are a bit tricky. There's geology, there's signal processing, there's big equations, there's rock physics. Not to mention data wrangling. Who's up for that?
- Big companies tend to buy one or two licenses of niche software, because it tends to be expensive and there are software committees and gatekeepers to negotiate with. So no-one who needs it has access to it. So you give up and go back to drawing wedges and wavelets in PowerPoint.
Okay, I get it, how is this helping?
We've been busy lately building something we hope will help. We're really, really excited about it. It's on the web, so it runs on any device. It doesn't cost thousands of dollars. And it makes forward models...
That's all I'm saying for now. To be the first to hear when it's out, sign up for news here:
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Seismic models: Hart, BS (2013). Whither seismic stratigraphy? Interpretation, volume 1 (1). The image is copyright of SEG and AAPG.