In answer to Ian Moffat's comment

Ian Moffat comments on my last post ( https://www.dhirubhai.net/posts/godfried-wasser-a0892222_petrophysics-is-modeling-your-reservoir-activity-6994418397698539520-ayfe?utm_source=share&utm_medium=member_desktop) :

Ian Moffat??

Oil and Gas Director and Executive, Calgary, Alberta, Canada:

and how is this different than what we were doing a couple of decades ago which is to take all the available data on reservoirs from core and wireline logs, calculate a distribution with P10 and P90 and then apply that to your reserve analysis?

Sorry, I'm sure there is something special here but I just think we were already doing this a long time ago.

Open to hearing the explanation.

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My answer is a bit long and thus this article:

Hi Ian

I think what we do is novel, enumerate up to 50 data columns of reservoir properties summarized in a core ‘description’ to be compared with wireline log responses. We thus quantify and analyze the reservoir and the factors that ‘make a reservoir tick'. I think that is a unique approach. ?I do realize that I have seen, (especially amongst carbonate sedimentologists) the use of data columns in descriptions identifying the fossil content and even some pore types in those columns.

Over the last 40 years in industry, especially in clastics, most emphasis in core examination though has been on identifying sedimentary features of such as structures, contacts, and contact types, as well as a rough estimate of porosity (often not even specifying effective versus ineffective porosity) and grain size distributions (not very precise though – for example in the Montney trying to differentiate silt size in microns, I think Howie King came closest).?Compositional data is greatly lacking. Mostly core examination was done to come up with sedimentary or sequence stratigraphic interpretations. If you look back over the years as to how those interpretations changed you may wonder if we ever get to agree on any depositional setting.

How many wells were successfully drilled based on these interpretations? Yet this was often the main goal of such core descriptions. During my career, I proposed many successful wells, mostly based on reservoir mapping rather than based on depositional interpretation. Although it is useful to have an idea of sedimentary setting, it has not led to significant insights into reservoir characteristics or identifying succesful drilling locations.

Using one or two thin sections to measure clastic reservoirs has been the most common practice and it certainy was NOT part of the routine.?Often petrographers, these days, only do a qualitative description as point counting is to cumbersome and ‘expensive’. ?Using thin sections routinely and statistically like we do when calibrating our core 'descriptions' to the log response is rare.?

We create LAS (Log ASCII Standard) files from our core ‘description’ data (which we give the extension ‘.CAS’ file or Core ASCII standard) to be included in petrophysical analysis. This is novel. ?Thus, we can cross plot and analyze many core-log relations and derive many algorithms other than simple CPOR-KMAX relations. Ever tried to measure clay content in core good enough to make cross plots with the Gamma Ray or other wireline logs??We can do that. We come up with multi-mineral analysis from logs that are (more) consistent with our core measurements and then extrapolate it to wells without core.

I hope this answers your comment which is indeed pertinent to the topic.