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Friday
Dec282012

Cope don't fix

Some things genuinely are broken. International financial practices. Intellectual property law. Most well tie software. 

But some things are the way they are because that's how people like them. People don't like sharing files, so they stash their own. Result: shared-drive cancer — no, it's not just your shared drive that looks that way. The internet is similarly wild, chaotic, and wonderful — but no-one uses Yahoo! Directory to find stuff. When chaos is inevitable, the only way to cope is fast, effective search

So how shall we deal with the chaos of well log names? There are tens of thousands — someone at Schlumberger told me last week that they alone have over 50,000 curve and tool names. But these names weren't dreamt up to confound the geologist and petrophysicist — they reflect decades of tool development and innovation. There is meaning in the morasse.

Standards are doomed

Twelve years ago POSC had a go at organizing everything. I don't know for sure what became of the effort, but I think it died. Most attempts at standardization are doomed. Standards are awash with compromise, so they aren't perfect for anything. And they can't keep up with changes in technology, because they take years to change. Doomed.

Instead of trying to fix the chaos, cope with it.

A search tool for log names

We need a search tool for log names. Here are some features it should have:

  • It should be free, easy to use, and fast
  • It should contain every log and every tool from every formation evaluation company
  • It should provide human- and machine-readable output to make it more versatile
  • You should get a result for every search, never drawing a blank
  • Results should include lots of information about the curve or tool, and links to more details
  • Users should be able to flag or even fix problems, errors, and missing entries in the database

To my knowledge, there are only two tools a little like this: Schlumberger's Curve Mnemonic Dictionary, and the SPWLA's Mnemonics Data Search. Schlumberger's widget only includes their tools, naturally. The SPWLA database does at least include curves from Baker Hughes and Halliburton, but it's at least 10 years out of date. Both fail if the search term is not found. And they don't provide machine-readable output, only HTML tables, so it's difficult to build a service on them.

Introducing fuzzyLAS

We don't know how to solve this problem, but we're making a start. We have compiled a database containing 31,000 curve names, and a simple interface and web API for fuzzily searching it. Our tool is called fuzzyLAS. If you'd like to try it out, please get in touch. We'd especially like to hear from you if you often struggle with rogue curve mnemonics. Help us build something useful for our community.

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Reader Comments (2)

This is an interesting approach, Matt.

I was involved in the original POSC effort to sort out the tool/curve mnemonic soup, the Practical Well Log Standards (PWLS) initiative, and our experience on this project may provide some guidelines for future initiatives. At the time I was running the Recall Database software development team at Baker Hughes, and along with Craig Shields (also Baker) and Dave Camden of Flare, we approached Cary Purdy at POSC with a proposal for an improved categorisation of log and curve mnemonics. This proposal was enthusiastically taken up by POSC, funding was provided by a number of Oil Companies, and the project launched.

The aim of the project was not to simply collect all of the mnemonics in use, but to provide a generic classification for each tool/service and curve name. The project also introduced the concept of the business value of a curve – “high” for curves used on a day to day basis by the petrotechnical community, “medium” for curves used occasionally to re-calculate or validate high business value curves, and “low” for curves that would only be of interest to the acquisition company.

Each curve mnemonic would be classified by the following:
> Its mnemonic name
> A code identifying the acquisition/logging company
> A Curve description
> A business value
> A property type – effectively the Schlumberger property type
> A generic, industry standard name (eg: GR)
> A generic domain mnemonic (eg: FM (formation), BH (borehole), ACQ (acquisition)…)
> A generic technique mnemonic (eg: IND (induction), LAT (laterolog)…)
> A generic property (eg: RES (resistivity), SLO (slowness)…)
> Up to two qualifiers to further define the classification
> A generic unit class for the measurement

A couple of examples:

Mnemonic.................PE.............................................M2R1
Company code.........150 (ie Baker)...........................150
Description...............Photoelectric cross section.......2 foot vertical resolution matched res.
Business value.........High..........................................Medium
Property type............Photoelectric_Factor.................Array_Laterolog_Resistivity
Generic name...........PEF...........................................RES
Class domain...........FM.............................................FM
Class Technique...... ................................................LAT
Class property..........PEF...........................................RES
Qualifier.................... ...............................................ARR (ie array)
Unit class..................b/e.............................................ohm.m

A full description of the project and its deliverables can be found at: http://w3.energistics.org/PWLS/pwls_20.htm

The project ran for several years, and covered most of the main mnemonics in use in the industry at that time. However, as can be seen form the examples above, there was a fair amount of overlap between the property type classifications and the generic PWLS classification, and this led to a certain amount of friction between the service companies involved in the project. Also, some acquisition companies were a lot more forthcoming over the submission of their mnemonic lists than others, the wireline operators being ahead of the LWD operators.

I do believe that this project provided an excellent foundation to the classification of the borehole measurements acquired while drilling and logging. It’s a pity that it did not receive the industry support required to keep it evergreen

February 6, 2013 | Unregistered CommenterChris Hamley

@Chris: Thanks for this comment the other day — apologies for not responding sooner, but I'm on the road. Stuck in a blizzard at the moment...

Thanks for the background on this POSC / PWLS effort. I assume by 'industry support' that you mean there wasn't the hoped-for buy-in. This seems typical of most standards efforts in our industry. I wonder what's driving that? It can't be easier or quicker to roll your own every time - software companies aren't that flush.

The metadata framework you've given looks useful. I wonder what the path forward is -- I'm certain the Internet can help link data here, especially when it's in the public realm, as it tends to be here in Canada.

February 8, 2013 | Registered CommenterMatt Hall

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