Patent attributes
A wellbore assembly includes a wellbore string and a cement retainer. The wellbore string is disposed within a cased wellbore. The cement retainer is releasably coupled to the wellbore string and defines, with a wall of the casing, an annulus. The cement retainer includes a housing, a valve, and a packer. The flapper valve is attached to and disposed within the bore of the housing. The flapper valve moves between a closed position, in which a fluid pathway of the cement retainer is closed, and an opened position, in which the fluid pathway is opened for fluid to flow downhole out of the cement retainer. The wellbore string opens, with the packer set on the wellbore, the flapper valve by stinging the flapper valve and allowing cement to flow downhole from the wellbore string to the target zone to remediate the wellbore at the target zone.