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.

Business Problem: finding the right log data

The Practical Well Log Standard (PWLS) was developed to address several issues around the management and use of valuable well log data, which companies may use over decades. These issues make it difficult for oil and gas professionals—both generalists and experts alike—to find and use the data because of:

  • The sheer volume of measurement types, called curves. The industry has about 50,000 known curve types, of which only about 500 of them are deemed most important and valuable. New ones are being created frequently.
  • Inconsistent, often cryptic curve names, called mnemonics, which makes it difficult to discern the different types of curves and which are the most important.

These issues presents several problems for data loading and acquisition, including these:

  • How do you sort “useful data” from ancillary data?
  • How do you maintain consistent ‘load-lists’ throughout your organization?
  • How do you know which data to load and which to archive?

The result of this confusion can be lost data, lost information and wasted time. Furthermore, 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.

What is PWLS and how does it help?

PWLS categorizes the obscure mnemonics used for oilfield data and relates them to the marketing names for logging tools that make those measurements—using plain English. PWLS provides an industry-agreed list of logging tool classes and a hierarchy of measurement properties and applies all known mnemonics to them.

The main goal of PWLS is to support the classification of well log property measurement data that are commonly used by oil and gas companies, and to use this classification as a tool to support general queries over large populations of channels.

With this type of classification, PWLS makes it possible to do queries such as “give me all the gamma ray logs” and have a store return all gamma ray logs (channels), from all vendors, regardless of the variety of vendor mnemonics used to identify gamma ray data.

As the basis for this categorization of channel data PWLS provides an industry-agreed upon standard hierarchical list of property names, which are used for consistency and validation of those names.

PWLS—the lists of properties, tools, codes, and mappings of relationships among them—is available for download so that organizations can implement them into stores and applications. PWLS is also integrated into Energistics domain data transfer standards WITSML, RESQML and PRODML, through Energistics Common Obects, the set of components shared by the three domain standards, and in the Energistics Transfer Protocol (ETP).

Use of PWLS increases efficiencies for companies through:

  • Easier access to the right data,
  • Improved understanding of well log data,
  • Increased confidence in processed data and
  • Better understanding and access to well log data by non-petrophysicists.

Process Overview for v3.0

The lists that comprise PWLS v3.0 have been compiled from multiple sources, mostly through feedback from oilfield service companies about their respective tools and technology. In addition to this direct input, other sources of data included: previous versions of PWLS, other existing well known industry sources, and list of operator internal mnemonics.

Assembling such a list based on frequently changing technology is always just a snap shot at a specific time and a part of the scope for PWLS v3.0 is a commitment from the service companies to make this information available on a more frequent basis so it can be published in a timely manner.

Energistics technical staff did the initial aggregation and analysis of the data, and then, per Energistics standards process, a release candidate of PWLS v3.0 was posted for a 90-day review period. To help with the aggregation and reconciliation of review feedback, meetings were held at 30, 60 and 90 days.

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

Standard Link
Practical Well Log Standard  v1.0 Executive Summary  HTML
Practical Well Log Standard v1.0 Release  HTML
Practical Well Log Standard v2.0 Release HTML