Annex 3 - Plug and abandonment work programme
Annex 3 to The Danish Working Environment Authority (WEA) guideline 65.2.2 on Health and safety aspects regarding offshore well operations
Appendix A3 outlines the minimum required documentation to be submitted with regard to plug and abandonment operations.
In the following, only the relevant information for the chosen solution is required.
Information about scope of work
The programme shall include the abandonment objectives of the planned plug and abandonment operations. This shall include the objectives for each layer to be abandoned.
Information about the well
The programme shall include:
- summary of the last interpreted calliper/logging survey if available
- well history and previous intervention(s)
- well and reservoir data which could be a potential hazard (scale, wax, CO2, H2S, etc.)
- information about casing and tubing restrictions
- equipment status
- well integrity status
- well schematic prior well operations
- well barriers schematic stating primary and secondary barriers prior well operations
- pore pressure and fracture gradient profile along the wellbore and its stratigraphy
- well geology if not provided with the above profile.
Information about the well operations
The programme shall include:
- well geology with identification and assessment of flow potential from hydrocarbons and water sources/reservoir
- well schematic of the proposed solution(s)
- well barriers schematic stating primary and secondary barriers of the proposed solutions
- verification of the barriers to be used as permanent barriers
- detailed programme of the operation including planned tests and their acceptance criteria to be achieved for all safety and environmental critical elements
- detailed programme of the contingencies if any including planned tests and their acceptance criteria to be achieved for all safety and environmental critical elements.
Information about the risk assessment – ALARP principle
The programme shall include the risk assessment, cf. section 1.
- assessment of subsurface conditions and identified potential hazards shall be stated, i.e. all potential leak paths to surface or intra formations (crossflows)
- identified risks shall be recorded and stated and mitigation measures shall be specified and implemented
- residual risks shall be as low as reasonable practicable (ALARP).
Information about independent verification
The programme shall include independent well verification, cf. section 4.
Information about dispensations
The programme shall include the dispensations from the operator’s own management system/standards and justifications.