Chapter Six - Well Barriers

Abstract

Understanding the physical properties of well barriers, where the barriers are located, how they are tested, and the actions to take if a barrier fails, are critical skills for anyone working in completions or interventions. Barrier elements and the barrier envelope often change during interventions. Personnel working in completions and interventions must be able to clearly identify each change of barrier element, and how the barrier envelope changes throughout the operation. Barrier diagrams are now incorporated in many work programmes by operating companies which clearly identify primary and secondary barrier envelopes, the individual barrier elements, and how they should be tested. This excellent system, if properly implemented, will mean those tasked with carrying out the work are always clear about where barriers are, how they change as work progresses, and crucially, how to respond to a barrier failure.