Issues related to the preparation and/or abandonment should be included in the Well Planning Document. These could be related to a new well with or without a conductor installed or could be related to the abandonment of an existing well as a preparation for side tracking.
Conductor
Pre-installed conductors may need to be repaired or replaced.
Talon connector have a reputation of failing and therefore have to be taken out before the new well is drilled.
Issues to address are:
- Curved conductor or straight conductor
- If curved conductor, which direction?
- Conductor shoe depth
- Drive only or drill and drive
- Junk in conductor
- Circulation ports (MCJ, CGC) or not
Abandonment
To abandon the well, the X-mass tree needs to be taken off, and the BOPs need to be installed. Before taking off the tree, barriers need to be installed in the well.
The abandonment procedures depend on legislation and reservoir management
If reservoir management requires that the existing open formations are isolated to prevent cross flow, often plugs have to be set and the completion has to be pulled. Milling the packer(s) to isolate the formations may be required.
If cross flow between the perforated intervals is allowed, a simpler method can be used. A plug can be set in the upper production packer (act as a cement retainer). On top of this packer a 500 ft cement plug is set. For setting this cement plug consider using the existingg production tubing.
Other issue to be addressed:
- Well kill considerations
- Recovery of completion
- Side track options
- Casing pressure test required
- workover/ abandoment fluids: What type of mud is behind the casing. is there a rsikl of contamination. will the fluid contact the reservoir and cause mpairment?