The words used in Formation Evaluation do not all have a definitive and universally agreed meaning. To create an authoritative reference, SPWLA has developed this collaborative online glossary that will allow members to contribute terms and definitions in multiple languages.

The present glossary was primed with the legacy glossary of the SPWLA (1984-1997), which included 1,555 definitions.

There is a tab at the top of each English entry for a translation to one of the target languages for this glossary:

• en - English
• es - Spanish
• fr - French

If a translation exists in one of the target languages, the language tab at the top will be orange. If a translation does not exist, the tab will be gray.

• Anyone can read the glossary, but only SPWLA members may write or edit entries. Want to help? Learn aboutBecome an SPWLA Member.
• Contributions are limited to terms and definitions used in the upstream oil and gas industry, with an emphasis on formation evaluation.
• Images that clarify definitions may be added, but non-definition material (articles, figures, tables, etc.) may not be posted. Please do not add images for which you do not hold the copyright.
• Any entries not conforming to these guidelines or to SPWLA standards of professionalism will be removed by peers or SPWLA staff.

• You may search for any term or acronym by simply typing it into the search box at the top.

• You may also browse entries alphabetically using the links below:

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Before you start editing or creating entries, you should practice using the wiki on the playground. You'll find instructions on the page. You can also try any of the instructions below in the playground.

A glossary entry should require very little formatting. You can, however, visit the Syntax page to learn more about Wiki syntax.

1. Navigate to the English term.

If a translation exists in one of the target languages, the language tab at the top will be orange. If a translation does not exist, the tab will be gray.

2. Click the abbreviation tab for the language you will use.

You will be invited to create the page.

3. Create and save the page.

The tab for the translation you added should now be orange.

By the way, this Welcome page needs to be translated, too!

1. Navigate to index (alphabet letter) page that your term begins with.

2. Open the page for editing.

3. Add the term where it belongs. Put two brackets around your new term.

 [[My New Term]]

It is helpful to look at existing terms for the format.

4. Save the page.

5. Click on the link – you will be invited to create the page.

6. Create and save the page.

1. Navigate to the English term.

If a translation exists, the language tab will be orange. If a translation does not exist, the tab will be gray.

2. Click the abbreviation tab for the language, or edit the English term if it is needed.

3. Make your change(s) in the editor.

4. Make a note about the change you made under the editing box

• If it is a minor change, check the Minor Changes box before saving.

• For bigger changes, put a short note in the Edit Summary field explaining what you did.

5. Save the page.

A wiki is only useful when an active community contributes to it and monitors it. Here are some notes about reviewing entries.

See the Login and Permissions page for help with logging in or your permission to edit the wiki.

Send questions or comments about the wiki itself to webmaster@SPWLA.org.