Packing for separating areas behind a string of casing in a borehole

摘要

Packing for separating areas behind a string of casing in a borehole, with a casing tube which serves as a mandrel of the packing, an extendable packing collar, and a first socket displaceable in a sealed-off manner on the casing tube, and a packing-collar socket secured to the casing tube in a sealed-off manner. Secured to the casing tube in a sealed-off manner is a sleeve in which the thicker upper part of a sliding sleeve engages, which part is sealed off at the inside of the sleeve and the outside of the casing tube. The thinner lower part of the sliding sleeve partly protrudes in between the casing tube and the packing collar and is sealed off from both. The first socket of the packing collar slides in a sealed-off manner on the sliding sleeve. A non-return valve in the casing tube connects its inner space and its outer side inside the packing collar. A bore in the lower part of the sliding sleeve connects the outer side of the casing tube and the inside of the packing collar. Another bore in the casing tube above the upper part of the sliding sleeve connects the inner space of the casing tube to the inner space of the sleeve.