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Practical Well Log Standard (PWLS)

What is PWLS?

The Practical Well Log Standard (PWLS) provides an industry‑agreed, hierarchical list of standardized Property Kinds and mappings to Quantity Classes used to categorize oilfield measurement data.

PWLS enables consistent classification, discovery, and aggregation of measurement data—commonly referred to as curves or channels—across companies, tools, and systems.

Why PWLS Is Needed

Well‑log measurements are produced by many service companies using proprietary naming conventions and mnemonic codes.

The same measurement (for example, gamma ray, density, or resistivity) may be labeled differently across vendors, and mnemonics are often shortened codes that are not self‑descriptive.

This creates challenges for:

  • Discovering relevant data across large datasets
  • Comparing measurements across vendors
  • Automating data ingestion and analysis workflows

PWLS addresses this by providing a standardized classification system that allows disparate measurements to be mapped to common Property Kinds, improving data discoverability, consistency, and interoperability.

Relationship to the Curve Catalog

PWLS defines what a measurement means using standardized Property Kinds.

The PWLS Curve Catalog documents how those measurements are labeled in practice by different companies through mappings from proprietary curve mnemonics (channels) to PWLS Property Kinds.

Starting with PWLS v4.0, company‑specific mnemonic listings were removed from the PWLS standard and are now maintained separately in the Curve Catalog.

This separation allows:

  • PWLS to remain stable, concise, and vendor‑neutral
  • Curve mappings to evolve independently
  • Companies (including non-members) to contribute and update their mappings without requiring a new PWLS release

How PWLS Is Used

PWLS is typically implemented in data stores and software systems to:

  • Classify incoming measurement data using Property Kinds
  • Enable querying across datasets using standardized categories
  • Support data integration across vendors and domains
  • Improve automation and analytics workflows

By mapping proprietary mnemonics to standardized Property Kinds, systems can operate on consistent semantics rather than vendor-specific naming conventions.

Important

PWLS provides classification and meaning for measurements.
It does not prescribe naming conventions or require specific implementations.

Scope Expansion in PWLS v4.0

Scope Expansion

While originally focused on well‑log data, PWLS v4.0 extends to a broader range of subsurface data, including seismic attributes and interpreted properties.

This evolution positions PWLS as a cross-domain classification framework spanning wells, geophysics, and reservoir workflows.

PWLS Distribution Formats

PWLS v4.0 is distributed in multiple formats to support different use cases:

  • XML (EML v2.3 PropertyKindDictionary) for system integration
  • Excel workbook for human-readable and filterable access
  • EPC packages for use with Energistics domain standards

All formats contain the same underlying Property Kind definitions.

Learn More

Participation

PWLS is developed through Energistics industry collaboration.

Participation in the development of the PWLS standard is available through Energistics membership: https://energistics.org/membership/

PWLS Curve Catalog vs PWLS Contribution

Contributions to the PWLS Curve Catalog are open to all companies and do not require membership.
Contributions to the PWLS standard itself are managed through the Energistics Consortium.