Improvements in or relating to well abandonment

摘要

A method and apparatus for the combined cleaning and plugging of an annulus in a well across a longitudinal section of the well were the annulus is located outside a conduit in the well. The conduit is perforated over the longitudinal section. Washing fluid is passed through the longitudinal section to clear material in the annulus before the longitudinal section is plugged. Pressure variations are created in the washing fluid by use of a flow modifier device to pulse the washing fluid. Embodiments include creating pressure variations in the plugging material.