Definition(s)
Annular pressure buildup (APB)
Pressure generated within an annulus by thermal expansion of wellbore fluids, typically during production. NOTE APB can also occur during drilling operations when trapped annular fluids at cool shallow depths are exposed to high temperatures induced by fluids circulating from deep, hot hole sections. This thermally induced pressure is defined and listed in API 90 as thermal casing pressure. NOTE 2 Can also occur from migration of formation fluids, as defined in API 90.
Source: API RP 96, Deepwater Well Design and Construction, First Edition, March 2013. Global Standards
Annular Pressure Buildup (APB)
Pressure generated within a sealed annulus by thermal expansion of trapped wellbore fluids typically during production. May also occur during drilling operations when trapped annular fluids at cool shallow depths are exposed to high temperatures from fluids circulating in deep, hot hole sections. This thermally induced pressure is defined and listed in API RP 90 as thermal casing pressure. APB is also referred to as annular fluid expansion (AFE).
Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards