For wells in Western Canada, the second and third characters of the UWI well identifier are used for the Location Exception or LX. The LX can contain both letters and numbers that represent embedded information and that’s great but it can also be confusing because the meaning can vary from province to province. In an effort to make sense of this, I will list what the LX meanings are by province.
In Saskatchewan, the LX is used both as an indicator of which portion of the LSD the well is drilled in (the first character) and it’s also a sequence number to represent the order in which wells are licensed in the same portion of the LSD (2nd number).
Here is a chart that shows the general rules for the LX in Saskatchewan. In general the letters refer to sequence numbers larger than 9. The exception is CC which means “Cancelled Well”.
|Saskatchewan LX General Rules|
|First Character||Description||Second Character||Description|
|0 to 4||For vertical wells an LSD is divided into 5 parts. 0 is the center, the SE 1/4 is 1, the SW 1/4 is 2, the NW 1/4 is 3 and the NE 1/4 is 4||Sequence number 0 to 9 to Z where A is 10, B is 11, etc.||Represents the order in which well licenses are issued in the same LSD. For example, 41/07-30-09-01W2/0 (or 14107300901W200) would be the first well licensed in the NE 1/4 of LSD 07 of section 30|
|5||Wells drilled on south boundary of a road allowance||Sequence number 0 to 9||The first well drilled on the South boundary of the lsd is 51 and second 52 and so on.|
|6||Wells drilled on West boundary of a road allowance||Sequence number 0 to 9.||The first well drilled on the West boundary of the lsd is 61 and second 62 and so on.|
|7||Wells drilled at the center of a section or quarter section on the LSD boundary line||Reference number to closest LSD, 0 to 9||70 to 74 refer to wells in the center of the quarter section and 75 to 79 indicate wells in the center of the section|
|8||Wells drilled on the boundary line between LSD’s||Sequence number 0 to 9.||The first well drilled on the boundary will be 81, the second is 82 and so on.|
|9||Indicates a directional well drilled into another LSD||Sequence number 0 to 8 to Z where A is 9, B is 10, etc.||Represents the order in which directional well licenses with the bottom hole in the same LSD are issued. Note that A means 9, not 10 as it does above. For example 93/08-11-008-08W2/0 (193081100808W200) is the third directional well drilled into LSD 08 of section 11.|
|C||CC means cancelled well||C||CC means cancelled well|
|9||99 means the exact position in the LSD is unknown||9||99 means the exact position in the LSD is unknown|
I’ve tried to keep this Saskatchewan list as simple as possible but you need to be aware that there can be exceptions to these general rules. You can click on the link below to get the complete details of how the LX numbers are assigned in Saskatchewan.
Alberta and Manitoba
Alberta and Manitoba both use letters in the LX in a very similar fashion but there are some differences. The letters in the location exception, LX will appear in the first character of the LX and are used to describe the well spacing unit and position. The second character of the LX is used to describe the drilling sequence number and the maximum is 9 in Manitoba, so no letters are used in the second character, unlike Saskatchewan. For example, 02/03-25-004-22W1/0 (102032500422W100) is the second well drilled in the 40 acre LSD of section 3. Another example, W0/04-12-016-15W4/0 (1W0041201615W400) means this is the first well drilled in west road allowance for LSD 04 of section 12. In Alberta, letters are often used for the sequence number.
The complete list of spacing descriptions used in the Alberta/Manitoba location exceptions is in the table below.
|AB/MB Location Exception Codes for First LX character|
|Code||Well Spacing Unit and/or Position|
|0||– Forty Acre Spacing or more – usually center of LSD|
|A||– Twenty Acre Spacing or less – S.E. quarter of LSD|
|B||– Twenty Acre Spacing or less – S.W. quarter of LSD|
|C||– Twenty Acre Spacing or less – N.W. quarter of LSD|
|D||– Twenty Acre Spacing or less – N.E. quarter of LSD|
|F||– Alberta Only, Farm water well|
|S||– Road Allowances wells located South of LSD|
|W||– Road Allowances wells located West of LSD|
|AB/MB Location Exception Codes for Second LX character|
|0||– 1st well in the location|
|2||– 2nd well in the location|
|3||– 3rd well in the location to the maximum of 9 for MB. AB will also use letters for the drilling sequence, A to Z for sequences higher than 9|
In BC the 2 characters of the location exception are used a little differently. As in other provinces, the 2nd character of the LX is still used as a sequence number and can be both numbers and letters. The first character, however, is used by CWD to assign a letter A to Z, in order to distinguish wells that have been authorized but not drilled.
UWI’s issued by the government will have 0 as the first LX character but UWI’s for authorized but not drilled wells will be assigned a letter in this position using a formula that insures the UWI remains unique since it’s used as the primary key in the database. The reason we need to do this is because when BC issues a well license (Well Authorization Number – WAI) to authorize a new well, they also issue an “Expected UWI”. The expected UWI for these wells has no location exception so duplicate UWI’s can occur. Using letters in the first LX character ensures that the UWI remains unique and does not collide with any existing UWI’s for drilled wells.
Once the well is drilled, a permanent UWI is issued by the BC authority and the UWI with a letter in the first character is replaced with the permanent one. This means that any BC well you see in the database with a letter in the first position of the 2 character location exception has been authorized but not drilled. There are many cases where a well may have been authorized many years ago and never drilled so these UWI’s remain in the database. There are over 7,000 of these currently in the database.
In summary, you can see that there is a significant amount of information embedded in these two location exception characters and hopefully this explanation can help you sort it out a bit.
Follow us on LinkedIn