Wellbarrier

Wellbarrier is a term used in the oil and gas industry to describe a set of barriers intended to prevent the uncontrolled flow of formation fluids from a well to the surface or environment. The concept is central to well integrity and well control, and encompasses physical, procedural, and administrative measures.

Barriers can be physical components such as cement sheaths, casings, tubing, packers, and blowout preventers; barriers can be non-physical, including procedural controls, permits, and kill procedures. In many industry frameworks, barriers are organized into tiers or lines of defence, commonly described as primary barriers that isolate the wellbore, secondary barriers that provide redundancy, and tertiary barriers that provide surface containment.

Management of well barriers involves identifying barrier elements, assigning ownership, and verifying status through testing and surveillance. A barrier register tracks the presence and condition of each barrier, while regular integrity checks, independent verification, and change management ensure barrier effectiveness throughout the life of the well, including drilling, completion, production, and decommissioning.

The barrier approach is supported by regulatory and standards frameworks that emphasize barrier identification, testing, documentation, and continuous improvement. The aim is to reduce the risk of hydrocarbon releases and their potential environmental impact by maintaining clear, auditable protection against undesired flow.

Common related topics include well integrity, barrier management, cementing, casing, and blowout prevention.