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Prove it

How many times have you heard these?
• The signal:noise is lower (or higher/improved/reduced)
• It’s too thin to see (interpret/detect) on seismic
• You can’t shoot seismic in the summer (winter/snow/wind)
• More fold (bandwidth/signal:noise/data) is too expensive
• That won’t (will/can/can’t) work
• It looks geological (ungeological/right/wrong)

I say these sorts of things all the time. We all do. We feel like we’re bringing our judgment to bear, we’re exercising our professional insight and experience. It’s part of the specialist advisor role, which many of us play, at least from time to time. Sometimes, when time is short or consequences are slight, this is good enough and we can all move on to more important things.

Often though, we do have some time, or the consequences are substantial, and we need a more considered approach. In those situations, at least for most of us, it is not enough to trust our intuition. Our intuition is not a convincing enough reason for a decision. Our intuition is unreliable (Hall 2010).

Science is reliable. So challenge your intuition with a simple task: prove it. The bed is sub-resolution? Prove it. More fold costs too much? Prove it. This attribute is better than that? Prove it.

First, gather the evidence. Find data, draw pictures, make spreadsheets, talk to people. What were the acquisition parameters? What actually happened? Who was there? Where are the reports? Very often, this exercise turns up something that nobody knew, or that everyone had forgotten. You may even find new data.

Next, read up. Unless you’re working on the most conventional play in the oldest basin, there has almost certainly been recent work on the matter. Check sources outside your usual scope — don’t forget sources like the Society of Petroleum Engineers (spe.org) and the Society of Petrophysicists and Well Log Analysts (spwla.org), for example. Talk to people, especially people outside your organization: what do other companies do?

Then, model and test. If you’re measuring signal:noise, seismic resolution, or the critical angle, you’re in luck: there are well-known methods and equations estimating those things. If you want to shoot cheaper data, or operate out of season, or convince your chief that vibroseis is better than dynamite, you’ll have to get creative. But only experiments and models — spreadsheets, computer programs, or even just mind-maps — can help you explore the solution space and really understand the problem. You need to understand why shots cost more than receivers (if they do), why you can mobilize in June but not July, and why those air-guns in the swamp were a waste of time and money. Modelling and testing take time, but the time is an investment. Most projects are multiyear, sometimes multi-decade, initiatives. The effort you spend may change how you operate for many years. It’s almost always worth doing. If your boss disagrees, do it anyway. You will amaze everyone later.

Finally, document everything. Better yet, do this as you go. But do wrap up and summarize. You aren’t just doing this for the geoscientist picking up your project in five years, you’re also doing it for your future self. Since most interpretation tools don’t have built-in documentation capabilities, you’ll have to find your own tools — look for ones that let you add links and comments for a rich report you can easily share. Wikis are perfect. At each step, either find or pretend to be the most skeptical person in the world. Ask the tough questions. Doubt everything. Then prove it.


References
Hall, M (2010). The rational geoscientist. The Leading Edge 29 (5), 596 ff, DOI 10.1190/1.3422460.

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Into the mouth of the mouse

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