Unique Well Identifiers (UWI) in Canada

Every oil and gas well drilled in western Canada has a Unique Well Identifier. The UWI is not merely an administrative tracking number — it encodes the well's legal land description directly in the identifier itself. A person who knows how to read a UWI can extract the surface location, determine which province's regulatory system applies, and convert the identifier to GPS coordinates without consulting any external database.

This makes the UWI one of the most information-dense identifiers in Canadian energy data. It also makes it a source of persistent confusion for anyone who encounters it without a clear explanation of the format. This page breaks down the UWI structure, covers both the DLS and NTS variants, explains how to extract a legal land description from any UWI, and describes how Township Canada converts UWI locations to GPS.

Purpose: Standardized Well Identification

Before UWIs were standardized, well identification in Canada was a patchwork. Operators used internal tracking numbers; regulators used permit numbers; databases used different formatting conventions for the same location information. Cross-referencing well records across companies, regulators, and provinces was time-consuming and error-prone.

The UWI standard was developed by the Petroleum Technology Alliance of Canada (PTAC) and adopted by Canadian oil and gas regulators to create a single, consistent identifier that works across the industry. The standard is documented in the PPDM (Professional Petroleum Data Management) Association's Canadian Well Identifier specification.

Key regulatory bodies that use UWIs:

• Alberta Energy Regulator (AER): Uses UWIs for all well licences, well records, and production data in the Petrinex and SPIN2 systems.
• BC Oil and Gas Commission (BCOGC): Uses UWIs for wells in both the DLS Peace River block and NTS-referenced areas.
• Saskatchewan Ministry of Energy and Resources: Uses UWIs for well licensing and production reporting.
• Manitoba Department of Energy and Mines: Uses UWIs for Williston Basin well records.

The result is that a UWI issued by the AER for an Alberta well and a UWI issued by the BCOGC for a BC well follow the same structural rules, even though the location encoding differs between DLS and NTS variants.

The DLS-Based UWI Format

The majority of Canadian wells — those in Alberta, Saskatchewan, Manitoba, and the BC Peace River block — use DLS-based UWIs. The format has three segments separated by slashes:

Event Sequence / LSD Location / Event Suffix

Full Example

100/06-32-048-07W5/00

Breaking this down:

The location segment — 06-32-048-07W5 — is identical in format to a standalone LSD description. Anyone who can read an LSD can read the location out of a UWI directly.

Event Sequence Codes (First Segment)

The three-digit event sequence code identifies the type of well and, in some conventions, the licensing status:

The exact code list varies slightly by province and by the database system in use. In some systems, the first digit indicates the event type and the next two digits provide further classification. When in doubt, consult the specific regulatory body's UWI reference guide.

Event Suffix (Last Segment)

The two-digit suffix at the end of a UWI identifies which event at that location the identifier refers to. 00 is the first well drilled at the LSD. If a second well is subsequently drilled at the same surface location — a common occurrence with multi-well pads — it receives the suffix 02. A sidetrack of the first well receives 01.

This suffix system allows multiple wells at a single surface LSD to have distinct UWIs while sharing the same location segment.

Compact Format

Some databases store UWIs without slashes, compressing the three segments into a single string:

10006320480700 (removing slashes and the W from the meridian)

This compact format requires knowing the UWI structure to parse correctly. The first three digits are the event sequence; the next two are the LSD; the next two are the section; the next three are the township; the next two are the range; the single character that was the meridian W is dropped, and the meridian number is embedded in the range field; the final two digits are the event suffix.

Township Canada parses both slash-delimited and compact UWI formats.

Zero-Padding Conventions

Township and range numbers in a UWI are zero-padded to consistent widths: Township 48 appears as 048, Range 7 appears as 07. This is consistent with how these numbers appear in regulatory databases but differs from some casual notation conventions where leading zeros are dropped.

The NTS-Based UWI Format

Wells in British Columbia outside the Peace River DLS block — primarily in exploration areas covered by the National Topographic System — use an NTS-based UWI. The three-segment structure is the same, but the location segment uses NTS notation instead of LSD notation.

Full Example

100/094B-12-A/00

Breaking this down:

The location segment 094B-12-A identifies the NTS quarter-unit where the well surface is located. See The National Topographic System (NTS) Explained for a full explanation of map areas, sheets, and blocks.

NTS-based UWIs are most common in the BCOGC database for exploration wells in non-Peace River areas of BC, including Montney wells east of the Peace River block boundary and exploration wells in northern BC.

Extracting a Legal Land Description from a UWI

The practical value of understanding UWI structure is being able to extract the surface location directly from the identifier, without database access.

DLS UWI Extraction

Given 100/14-27-048-05W5/00:

1. Strip the event sequence (100) and suffix (00).
2. The location segment is 14-27-048-05W5.
3. This is the LSD description: LSD 14, Section 27, Township 48, Range 5, West of the 5th Meridian.
4. Convert using any DLS-to-GPS tool.

The surface location is in the Drayton Valley area of central Alberta, Township 48 Range 5 W5M — a productive area of the Pembina oil field.

NTS UWI Extraction

Given 100/094B-12-E/00:

1. Strip the event sequence and suffix.
2. The location segment is 094B-12-E.
3. This is the NTS reference: map sheet 094B, block 12, east half-unit.
4. Convert using an NTS-to-GPS tool.

The surface location is in northeastern BC, in the Liard Basin or southern Montney area.

Common Mistakes and Gotchas

Confusing Event Sequence with Location

In the compact format 10014270480500, the first three digits (100) are the event sequence — not part of the location. The location begins at digit 4 (14) and ends before the final two digits (00). Misreading the boundaries of each segment is the most common parsing error.

In the slash-delimited format, this confusion is less likely because the slashes clearly separate the three segments. When working with compact UWIs, always parse from the known segment widths: 3 digits event, then the location, then 2 digits suffix.

Meridian Encoding in Compact Format

In the slash-delimited format, the meridian is explicit: 07W5 means Range 7, West of the 5th Meridian. In the compact format, the W is dropped and the meridian number is incorporated differently depending on the implementation. Some systems encode it as part of the range field; others use a separate character. When parsing compact UWIs from a legacy system, confirm the specific encoding convention before processing in bulk.

Event Suffix vs. Sidetrack Number

The suffix 00 means the first event (the original well). Suffix 01 typically indicates a sidetrack — a well that deviated from the original hole. Suffix 02 indicates a second, separately licensed well at the same surface location. These have different meanings for production accounting and regulatory reporting. Using the wrong suffix when referencing a specific well in a database query returns records for a different event.

Surface Location vs. Bottom-Hole Location

The UWI encodes the surface location — where the wellhead is physically located. For directional or horizontal wells, the bottom-hole location (where the well terminates in the reservoir) may be in a completely different LSD or even a different township. Regulatory databases track both, but the UWI itself refers only to the surface. When a geologist describes a well as targeting a specific LSD, they may be referring to the bottom-hole location, not the UWI surface location.

DLS vs. NTS UWI Confusion

A UWI that begins 100/094B- is clearly NTS-based (the map area code is three digits followed by a letter). A UWI that begins 100/06-32- is clearly DLS-based (the location segment begins with a two-digit LSD number). However, in compact format or in databases with inconsistent formatting, the two types can be difficult to distinguish without knowing the regional context. BC wells near the DLS/NTS boundary require particular care.

Regulatory Database Format Variations

The AER's ST series reports, SK Ministry databases, and BCOGC records each have minor variations in how UWIs are displayed — some use hyphens within the location segment, some use spaces, some omit the W in the meridian designator. Township Canada normalizes these variations when parsing UWI input.

UWI Lookup and Regulatory Databases

Several Canadian regulatory databases allow well lookup by UWI:

Petrinex (Alberta, Saskatchewan, Manitoba): The provincial production and compliance reporting system. Petrinex records link to AER well licences by UWI. Access is available to licensed operators.

AER SPIN2: The AER's Spatial Information (SPIN2) system allows public lookup of well locations by UWI, with map display and licence document access.

BC OGC eSubmission / BC Energy Regulator: The BCOGC (now restructured into the BC Energy Regulator) maintains a public well search by UWI with licence and production data.

geoSCOUT, Accumap, IHS Markit (now S&P Global): Commercial well databases that aggregate UWI-linked well data from all provinces and allow spatial query, cross-referencing, and export.

PPDM Well Master: The Professional Petroleum Data Management Association maintains a reference standard for UWI structure and a well master database used by data management professionals.

Converting UWI Locations to GPS with Township Canada

Township Canada converts DLS-based UWIs by extracting the LSD location segment and processing it through the standard DLS conversion pipeline. Enter a UWI in any of the following formats:

• Slash-delimited: 100/06-32-048-07W5/00
• Location only: 06-32-048-07W5
• Compact: 10006320480700

The converter identifies the location segment, validates the LSD, township, range, and meridian, and returns the GPS coordinates for the surface hole location. The result includes the parcel boundary on the survey grid, the quarter-section context, and export options for CSV or KML.

For NTS-based UWIs, use the BC NTS Converter with the NTS location segment from the UWI.

For a step-by-step explanation of LSD-to-GPS conversion — the core operation underlying UWI conversion — see LSD to Lat/Long. For the full DLS context that LSD descriptions sit within, see The Dominion Land Survey System Explained. For how UWIs are used in oil and gas workflows including well licence filing and database management, see Legal Land Descriptions for Oil and Gas.

Try a Real UWI Conversion

Enter 100/06-32-048-07W5/00 into the Township Canada converter to locate the well surface on the survey grid. The converter extracts the LSD 06-32-048-07W5, identifies it as LSD 6 in the SE quarter of Section 32, Township 48, Range 7 W5M, and returns the GPS coordinates near Drayton Valley, Alberta — in a producing area of the Pembina oil field.

For bulk UWI processing — common in well database audits and acquisition due diligence — the batch converter accepts a list of DLS-format UWI location segments and returns GPS coordinates for each. This is particularly useful when validating that a set of acquired well records places wells within the expected geographic area before importing into a production system.