PWLS provides an industry‑agreed, hierarchical list of standardized property names and mappings to quantity classes used to categorize oilfield data. A quantity class describes the physical dimension of a property (such as length or pressure), helping ensure that compatible units of measure (from the Energistics Unit of Measure Standard) are applied without mandating specific units.

PWLS also serves as the standardized property classification reference list used in the OSDU® Data Platform, enabling consistent identification, storage, and discovery of subsurface properties across domains such as wells, geophysics, and reservoir models.

When implemented in data stores or software systems, PWLS supports querying and aggregation of log data by standardized property kinds. By mapping locally named data to an agreed‑upon classification, PWLS improves data discoverability and interoperability across organizations and datasets.

PWLS v4.0 – 2026

To download PWLS v4.0, click here.

Starting with PWLS v4.0, the distribution format of the standard has changed. Previous versions were delivered only as Microsoft Excel spreadsheets. Now PWLS is distributed with the same content in multiple formats to help improve adoption and distribution; PWLS includes these files (which contain the same content in different formats):

• a PropertyKindDictionary XML (in EML v2.3 format) file (PWLS_PropertyKindDictionary_v4.0_eml23.xml) containing all the Property Kinds. This format is for the latest versions of the Energistics domain standards: WITSML v2.1, RESQML v2.2, and PRODML v2.3
• a Property Kinds Excel file (PWLS_PropertyKind_Dictionary_v4.0.xlsx) containing all the Property Kinds in a more human-readable and filterable format
• an EML v2.3 Energistics Packaging Convention (EPC) file (eml23_pwls40.epc) containing all the Property Kinds
• a RESQML v2.0.1 Energistics Packaging Convention (EPC) file (resqml201_pwls40.epc) containing all the Property Kinds

PWLS Curve Catalog

Also new in v4.0, PWLS is complemented by the PWLS Curve Catalog—a new, industry-supported public repository of company mnemonics (or channels) linked to PWLS Property Kinds.

The standard was changed to remove individual company listings of mnemonics from the PWLS standard itself (formerly contained in PWLS_Logs.xlsx). Companies can now publish their mnemonic listings and their mappings to PWLS Property Kinds through the PWLS Curve Catalog.

Creating a separate Curve Catalog allows companies—including non-Member companies—to publish their Log Curve and Tool listings at their convenience and does not require publishing a new version of PWLS.

Find out more at the PWLS Curve Catalog site.

PWLS v3.0 - 2021

Released March 2, 2021, PWLS v3.0 is a major update. The trend towards increased automation in data management in many workflows requires disambiguation as to the nature of log curves that have branded, company-specific or legacy mnemonics. A recording of a walkthrough presented by Energistics CTO, Jay Hollingsworth, is available and will provide insights into the updates included in PWLS v3.0. Click here to access the Download Standards web page. The download zip file contains the PWLS Properties and PWLS Logs spreadsheets as well as the Usage Guide.

PWLS History

PWLS v1.0 (February 22, 2001) represented the results of Phase I of the project, and was released by POSC. About 100 logging tools of the following types were addressed: Nuclear, Resistivity, Acoustic, Electromagnetic Propagation, and Magnetic Resonance. PWLS v2.0 (September 30, 2003)  covered about 100 logging tools of the types addressed in Phase I and additional types covered: Collar Location, Geometry, Fluid Density, Flow Meter, Pressure / Temperature, Element Analysis, Neutron Decay, Cement Evaluation, Spectral Gamma Ray, Directional, and Magnetic.

Access to prior versions