Annular barrier with expansion unit

Abstract

An annular barrier to be expanded in an annulus between a well tubular structure and a wall of a borehole downhole includes a tubular metal part having a first expansion opening, an axial extension and an outer face, an expandable sleeve surrounding the tubular metal part and having an inner face facing the tubular metal part and an outer face facing the wall of the borehole, each end of the expandable sleeve being connected with the tubular metal part, and an annular space between the expandable sleeve and the tubular metal part. Fluid inside the tubular metal part has a tubular pressure, and the annular barrier has an expansion unit having a first inlet in fluid communication with the expansion opening, a second inlet in fluid communication with the first zone and an outlet in fluid communication with the annular space. The expansion unit has an element movable at least between a first position in which the expansion opening is in fluid communication with the outlet and the tubular pressure being higher than the first pressure, and a second position in which the outlet is in fluid communication with the first zone and the first pressure being higher than the tubular pressure. The tubular metal part has at least one second expansion opening being fluidly connected with the first inlet.