The Pack off Bushing
has been designed to seal the annulus between the Liner system and the inner
string. For this purpose it provides interior and exterior seals. Depending on
well specifications those seal components consist of multiple o-rings or compact
in chevron type packing. Sealing is required to build up pressure in order to
activate the hydraulic accessories between the bushing and the plug/cups
system. The Pack off Bushing is located under the Setting Tool and above the Liner Hanger. Usually, the Pack off
Bushing is retrievable and locked in the Pack off Nipple or in the Setting Sleeve through a dog system on the Pack off Bushing.In this version
the interior seals provide a movement seal for the Stinger which is able to
slide through the Pack off Bushing at any time in operation.
A drillable Pack off
Bushing fulfils the same functions as a retrievable Pack off Bushing. The only
difference is the drillable Pack off Bushing will stay in place (e.g. in the Setting Sleeve or Pack off Nipple) and won´t be pulled out of the hole. A drill out trip with PDC bit or higher for this type of Pack off Bushing is necessary to restore the Casing bore ID.
Seals the annulus between the stinger and liner casing
Standard material: Viton – HNBR ; other material upon request