DLS - Dominion Land Survey
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The Dominion Land Survey system is the standard well identification system used in Alberta, Saskatchewan, Manitoba and in the Peace River block of British Columbia. The Unique Well Identifier (UWI) format is a coded 16 character string. The DLS UWI string looks like this:
|
Character |
SS |
LE |
LSD |
SC |
TWP |
RG |
W |
M |
P |
ES |
||||||
|
UWI Position |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
13 |
14 |
15 |
16 |
Each portion of the string is represented in logical order as follows:
|
Character |
UWI Position |
Description |
|
SS (Survey System) |
1 |
This Survey System code defines the Survey System in affect. In the DLS system the value of this position is always ' 1 '. S is also an acceptable abbreviation for this string. |
|
W (West) |
13 |
Defines the Meridian as "West" of 0° Longitude (Greenwich). This value is always set to ' W '. |
|
M (Meridian) |
14 |
Defined by the meridians of Longitude. 104th meridian is defined as ' 4 ', the 105th meridian is defined as ' 5 ', the 106th meridian is defined as ' 6 '. All wells in northeast British Columbia are defined as west of the sixth meridian (W6). |
|
RG (Range) |
11 12 |
Each area west of a Meridian subdivides east-west into Ranges. A Range is 9.7 km (6 miles) east to west. Acceptable values range from 01 to 30 |
|
TWP (Township) |
8 9 10 |
Each area west of a Meridian subdivides north-south into townships. A Township is 9.7 km (6 miles) north to south. Acceptable values range from 001 to 126 |
|
SC (Section) |
6 7 |
Ranked as the second smallest division to the Legal Subdivision, a section is 1.609 by 1.609 km (1 mile by 1 mile). Acceptable values range from 01 to 36. SEC is also an acceptable abbreviation for this string. |
|
LSD (Legal Subdivision) |
4 5 |
These values define the smallest division in the DLS system. Each subdivision is 402 by 402 m (1320 by 1320 ft). Acceptable values range from 01 to 16. LS is also an acceptable abbreviation for this string. |
|
LE (Location Exception Code) |
2 3 |
These values are used to define more than one well drilled in the LSD (Legal Subdivision defined below) and the sequence in which the wells were drilled. Positions 2 and 3 indicate the sequence in which the wells were drilled. The first well drilled is defined by a ' 0 0 ', the second well drilled is defined by a ' 0 2 ', the fifteenth well drilled is defined by a ' 1 5 ', etc. Acceptable values range from 00 to 19, excluding 01. The Location Exception code differs in a number of cases. For more information on possible changes to this code see Location Exception Code below. Note: Where more than one resource is penetrated by the same well an UWI must be identified for each resource using the above requirements when referencing that resource. |
|
P (Padding Character) |
15 |
An unused character in the DLS system and is therefore always either ' 0 ' or left blank. |
|
ES (Event Sequence Code) |
16 |
Indicates the significant drilling and/or completion operations at a well that yield a separate and unique set of geological or production data. Acceptable values range from 0 to 9, excluding 1. |
The following cases outline how the Location Exception Code format can change:
Note:
Where more than one resource is penetrated by the same well an UWI must be identified for each resource using the above requirements when referencing that resource.
Oil Sands Resource Area
The Oil Sands Resource Area defines the Location Exception code using a different method, which does not necessarily define a chronological order in which the wells were drilled. Acceptable values range from AA to HZ, excluding the use of the letters ' I ' and ' O ') with the sequence AA, AB, AC...AZ, BA, BB,...HX, HY, HZ.
Coal Resource Area
The Coal Resource Area defines the Location Exception code using a different method. They do not necessarily define a chronological order in which the wells were drilled. Acceptable values range from 1A to 9Z, excluding the use of the letters ' I ' and ' O ') with the sequence 1A, 1B, 1C...1Z, 2A, 2B,...9X, 9Y, 9Z.
Quadrants
When a drilling space unit is less than 16 hectares (4 acres) or one LSD, the Legal Subdivision is divided into Quadrants
Position 2 reflects the Quadrants as A, B, C and D. Each Quadrant measures 201 by 201 m.
Position 3 reflects the logical sequence in which the wells were drilled in the Quadrant. Acceptable values range from 0 to 9, excluding 1.
Road Allowances
A well drilled in a Road Allowance is defined as either south or west of the Legal Subdivision indicated in the UWI. Each Road Allowance is 20 m wide.
Position 2 reflects this with a ' S ' or a ' W '.
Position 3 reflects the logical sequence in which the wells were drilled in the Road Allowance. Acceptable values range from 0 to 9, excluding 1.
Freshwater Resources
Locations where Freshwater Resources are drawn on by the well are also identified using the Location Exception portion of the UWI.
Position 2 reflects the type of freshwater resource; F (wells), L (lakes), R (rivers).
Position 3 reflects the logical sequence in which the freshwater resources were activated. Acceptable values range from 0 to 9, excluding 1.
For detailed information on the Dominion Land Survey system see the topic.
Source References
Alberta Energy and Utilities Board, Guide 59: Well Drilling and Completion Data Filing Requirements (Calgary, Alberta; 3rd Edition, May 2001, Revised February 2003), pp 24 - 36.