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Primary or Typical Scenario
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Summary
A well is spudded at a location some distance from the location identified at the planning stage. The well is junked because of drilling problems and re-spudded nearby. After years of production, the well is plugged and abandoned. A few years later, the well is re-opened, re-entered and completed in a new formation.
Description
An operator plans a well in Alberta with the subsurface target Section 12. The surface location was assumed to be in LSD 3 (Site A in Figure 1) but on field investigation the terrain was unfavorable and LSD 14 (Site B) was selected. The well licence was issued for this surface location.
Figure 1: two well sites in Section 12.
The well was spudded and drilled ahead. However, at a depth of 1420 m the drilling assembly parted and could not be recovered. The well was abandoned, the rig was skidded about 10 m east on the same well site, and a new well was spudded. This well was successfully drilled to the target and was completed as an oil well.
After 14 years of production the original producing zone was depleted and abandoned. The well was recompleted in a new formation. This new production continued for another 7 years until it was no longer economical. The well was then plugged and abandoned.
Eight years later, a different operator obtained a new lease on Section 12 and applied for a new licence to produce from a different formation. The licence was issued, the well was re-entered, completed, and placed on production. There was no additional drilling.
CWIS identifiers:
- Well ID AB0012226 (for junked well)
- Wellbore ID AB001226B001 (for junked wellbore)
- Well ID AB0012345 (for re-spud well)
- Wellbore ID AB0012345B001
- Well Reporting ID AB0012345V001
- Well Reporting ID AB0012345V002
- Well Reporting ID AB0012345V003
How many Well Origins?
The Well ID is assigned to a unique Well Origin. Therefore, this case requires correct determination of how many Well Origins exist.
A Well Origin (PPDM baseline definition; see whatisawell.ppdm.org) is “the location on the surface of the earth…where the drill bit is planned to penetrate or does penetrate the earth to establish or rework a Well.”
At the planning stage, the drill bit was planned to penetrate the earth in LSD 3. A Well Origin exists in this planned location, according to the definition. However, it is only an approximation of the actual location. Even on the well licence, the surface coordinates taken from the well plat are not assured to be the exact surveyed location of the physical Well Origin. When the well is spudded, there is only one physical Well Origin although it may be associated with several sets of coordinates created at various times from planning to as-built survey.
A second Well Origin is created when the rig is skidded and the well is spudded again. The junked well has the original physical Well Origin. The re-spud well has a new surface location and therefore has a new Well Origin.
When the abandoned well is re-entered, the Well Origin has not changed. It is still the same physical penetration of the surface.
In conclusion, this example has two Well Origins: one for the junked well and one for the re-spudded well.
How many Well Identifiers?
The Well ID is assigned to a unique Well Origin. Therefore, this example has two Well IDs.
How many Well Reporting Identifiers?
There are three production streams over the life of this well. Therefore, this example has three Well Reporting IDs.
How many licences?
A well licence (in other jurisdictions called a drilling permit, well authorization, etc.) is not part of the Canadian Well Identification System. The licence is issued for regulatory purposes other than for identification. In this Alberta example, there are three licences: one for the original well, one for the re-spud, and one for the re-entry on a new lease.
How many UWIs?
The Unique Well Identifier is not part of the Canadian Well Identification System. However, CWIS assumes that the UWI will continue to be assigned to new well events in order to support legacy systems. This example has the following UWIs:
- UWI for the original well, subsequently junked and abandoned. It is considered a well because it drilled below 150 m (AER Directive 59).
- UWI for the re-spudded well (second drilling event) and initial production
- UWI for the recompletion and production
- UWI for the re-entry on the new lease (licence event) and production.
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