What a UWI Is and How to Read Alberta Well Identifiers

The Alberta Township Survey (ATS) Grid

The grid section of a UWI encodes location within the Alberta Township Survey system — meridians, townships, ranges, and sections. A township is roughly 12 km on a side, so the grid gives you immediate geographic resolution without a database. The research wells near a municipality guide uses this grid to set search radii. Understanding the ATS is the foundation for any location-based filtering in Alberta.

Formatted vs Unformatted UWI in Practice

A formatted UWI such as 00/04-12-046-08W5/00 uses slashes and dashes to separate grid components; an unformatted version strips those characters. Different datasets use different formats, and mismatches between them are a common cause of failed joins in manual research. A research platform that normalizes UWI formats eliminates this friction. The data sources comparison discusses format and accessibility limitations.

UWIs for Horizontal and Multilateral Wells

In horizontal wells, the surface location and the bottom hole can be kilometres apart. Separate UWIs may be assigned for the surface and bottom hole locations, reflecting the lateral length and target formation. Lateral length is a key design variable in tight oil and gas completions. The well status guide notes how status maps to service demand along that lifecycle.

Using UWI to Track a Well Across Its Lifecycle

Because a UWI is constant for the life of the wellbore, it is the stable key for tracking a well from drilling through production, inactivity, suspension, abandonment, and reclamation. Filtering or watching by UWI keeps the same well in view across data updates even as operators and licence numbers change. The watchlist guide shows how to monitor a specific well over time.

UWI and Licence Number: A Quick Reference

The licence number guide expands on the regulatory side of this pairing.

What UWI Stands For

UWI stands for Unique Well Identifier. It is the standardized identification code used by the Alberta Energy Regulator (AER) to distinguish every well drilled in the province. No two wells share the same UWI, and once assigned, a UWI stays with that well for its entire lifecycle — from initial drilling through production, inactivity, suspension, abandonment, and reclamation.

If you work with Alberta well data in any capacity — whether you are a service company researching operators, a consultant analyzing well histories, or a sales team building prospect lists — you will encounter UWIs constantly. They appear in AER ST37 well records, regulatory filings, production data, and well licence applications. Understanding how to read a UWI gives you a faster way to extract useful information directly from the identifier itself, without having to look up the full record.

The UWI format is not random. Every character has a specific meaning, and decoding a UWI tells you where a well is located, whether it is a surface or bottom hole location, and what type of well it is. This article breaks down each component so you can read UWIs at a glance.

How to Read the UWI Format

A standard Alberta UWI is 16 characters long and follows a fixed structure. Here is the breakdown of each section:

Characters 1–4: Unique well number. This is a sequential number assigned to the well within its grid cell. It differentiates wells that share the same location coordinates. Numbers range from 0001 upward.

Characters 5–10: Grid system designation. This section identifies the well's location within the Alberta Township Survey (ATS) system. It encodes the meridian, township, range, and section. For example, in the grid designation "000000," each digit position corresponds to a specific geographic coordinate component within the provincial grid.

Character 11: Well type suffix. A single letter that identifies the well type — for example, "A" for oil, "B" for gas, "C" for injection, or "I" for injection. This character tells you at a glance what the well was originally drilled for.

Characters 12–16: Licence number. This is the AER licence number assigned to the well, padded with leading zeros to fill five digits. The licence number is a separate identifier from the UWI, but it is embedded within the UWI structure for cross-referencing purposes.

A practical example: 00/04-12-046-08W5/00 is a formatted UWI that decodes into a specific well location in the Lloydminster area. Reading the grid section tells you the meridian (W5), township (046), range (08), and section (12). Even without a database lookup, this tells you the general area of the province where the well sits.

Surface vs Bottom Hole Location in a UWI

One important distinction in the UWI system is between the surface location and the bottom hole location. A well's surface location is where the drill rig sits on the ground. The bottom hole location is where the well terminates underground — which, in directional or horizontal wells, can be significantly farther from the surface pad.

In some cases, the UWI grid designation is based on the surface location, and a separate identifier is used for the bottom hole. When you are researching wells for service outreach, this matters because the surface location tells you where physical equipment and access roads are, while the bottom hole location tells you what geological formation the well is targeting.

For most prospecting and sales research purposes, the surface location is what you care about. When you find a well in a target region on a map or in a filtered list, the UWI's grid section confirms where that well physically sits. This is critical for geographic filtering — if you are building a prospect list for a specific area, the UWI tells you immediately whether a well is within your serviceable range.

How UWIs Differ from Licence Numbers

A common source of confusion is the difference between a UWI and a licence number. While the licence number is embedded within the UWI structure (characters 12–16), they are not the same thing:

The UWI is a geographic and type identifier. It tells you where the well is and what kind of well it is. It is based on the well's physical location in the Alberta grid system and does not change even if the well is transferred to a different operator.

The licence number is a regulatory identifier issued by the AER. It is tied to the specific drilling permit and regulatory record. The licence number appears in regulatory filings, well licence applications, and compliance documents.

In AER ST37 datasets, both identifiers appear. When cross-referencing wells across different data sources — for example, matching a well in a production dataset to a regulatory filing — you may need to use both the UWI and the licence number to make accurate connections. In FracturingHub, both identifiers are searchable, so you can look up a well by either code.

Using UWIs to Find Well Records

The practical value of understanding UWIs becomes clear when you start using them to research wells and operators. Here are the most common ways UWIs are used in Alberta oilfield research:

Searching AER datasets. When you download well records from the AER or use a research platform, the UWI is the primary key that ties everything together. Searching by UWI pulls up the specific well record — status, operator, location, dates, and drilling data — without ambiguity.

Filtering by region. Because the grid section of the UWI encodes geographic coordinates, you can filter or sort wells by their grid designation to isolate wells in a specific township, range, or section. This is useful when building a prospect list for a defined service area.

Cross-referencing filings. AER regulatory filings — suspension notices, abandonment applications, licence transfers — reference the well by UWI. If you find a filing that interests you, the UWI takes you directly to the well record for full context.

Tracking well history. A single UWI follows a well through its entire lifecycle. If you are tracking a well that went from producing to inactive, the UWI lets you monitor that specific well across data updates without losing the record.

Building watchlists. When you identify a set of wells worth monitoring — perhaps because they are in a target region or owned by a prospect operator — adding them to a watchlist by UWI ensures you catch status changes, operator transfers, or new filings as they appear. You can start exploring wells on the wells page or view them geographically on the map.

Common UWI Variations

While the 16-character format is standard, you may encounter variations depending on the data source:

Formatted vs unformatted. A formatted UWI includes slashes and dashes to separate the grid components (e.g., 00/04-12-046-08W5/00). An unformatted UWI strips those characters into a continuous string (e.g., 00041204608W500). Both represent the same well, but different datasets use different formats.

Legacy UWIs. Some older wells may have UWIs that do not conform to the current 16-character standard. These legacy identifiers still appear in historical records but may require manual cross-referencing.

Horizontal well extensions. Horizontal wells with long laterals may have separate UWIs for the surface location and the bottom hole, reflecting the distance between where the well starts and where it terminates underground.

When working across multiple data sources, check which format is being used. Mismatches between formatted and unformatted UWIs are a common source of errors in manual spreadsheet research. A research platform that normalizes UWI formats eliminates this problem.