Article of the Month – Stochastic and Multi-Deterministic Depth Conversion

In this month’s article, Alan Foum discusses Stochastic and Multi-Deterministic depth conversion and raises several key points on the topic of measuring and understanding the variability in both structure and the overall volume of prospects.

This is important as no depth conversion can ever be perfect and understanding the total range of possible depth scenarios is important to identify where your Best Technical Case model is situated with respect to the P50 case, such that you can gain confidence in your prediction of depth.

In a time where many hundreds of thousands of dollars have gone into the creation of Pre-Stack Depth Migration (PSDM) volumes, more and more geoscientists are using their PSDM’s for depth. However, an important question must always be asked…

“Does your PSDM represent your Low, Mid, or High case scenario?”

Our experience would indicate that many geoscientists within the industry presently view their PSDM model as the ‘only’ case! This assumption is fraught with danger and can relate to misplacing a well, misplacing geohazards (such as shallow gas) or mis-understanding the total size, shape and scale of a prospect.

As Alan discusses in his article, “The key points we need to understand are: i) what is the uncertainty level of our depth prediction ii) where does our model fall on the P10/P50/P90 distribution curve? and iii) How wide is the distribution curve?”

It is therefore a crucial step to take the time volume used to create the PSDM and perform a vertical depth conversion, such that a stochastic series of simulations can be leveraged to assess your prediction of depth.

We hope you enjoy the reading the article and if you’re a seasoned depth conversion veteran, then please get in touch here if you have the time to write an article that can help the wider geoscience community at large.


Read the article here.


Depth Conversion Training

If you would like formal depth conversion training, in both theory and practice, in either Velit (Petrel) or VelPAK (Kingdom) then we run a series of training courses which you might find interesting. You can click here to find out more.

If you’d like to know more about Velit then click here. To contact us for a free evaluation e-mail us on

The software is provided by S&P Global (who we partner with for Kingdom) with perpetual and subscription pricing available on request. We offer a series of Teams meetings throughout the evaluation to help you quickly step up the learning curve and enable you to see the results for yourself.