As defined in ISO 16530-1
The “Basis of Design Phase” identifies the probable safety and environmental exposure to surface and subsurface hazards and risks that can be encountered during the well life cycle. Once identified, these hazards and risks are assessed such that control methods of design and operation can be developed in subsequent phases of the well life cycle.
The “Design Phase” identifies the controls that are to be incorporated into the well design, such that appropriate barriers can be established to manage the identified safety and environmental hazards. The design addresses the expected, or forecasted, changes during the well life cycle and ensures that the required barriers in the well’s design are based on risk exposure to people and the environment.
The “Construction Phase” defines the required or recommended elements to be constructed (including rework/repair) and verification tasks to be performed in order to achieve the intended design. It addresses any variations from the design which require a revalidation against the identified hazards and risks.
The “Operational Phase” defines the requirements or recommendations and methods for managing well integrity during operation.
The “Intervention Phase” (including work-over) defines the minimum requirements or recommendations for assessing well barriers prior to, and after, any well intervention that involves breaking the established well barrier containment system.
The “Abandonment Phase” defines the requirements or recommendations for permanently abandoning a well.