| 摘要 |
A tubing retrievable completion assembly includes a surface-controllable, safety control valve interposed between the production tubing string and a production seal unit. A gas-lift safety valve is carried within a side pocket mandrel connected in the upper production string. The upper production string, production flow safety valve and gas-lift safety valve are run in and removed as a single unit from a single-bore hanger packer which is releasably anchored within the well casing. Separate concentric flow passages are provided through the packer bore for the upward flow of formation fluid through a production stinger conduit which extends through the packer bore, and for downward flow of lift gas through the annulus between the packer bore and the stinger conduit. The completion assembly is locked into place below the hanger packer by a latch having fixed and movable collets. Pressure equalization across the packer is obtained by closure of the gas lift safety valve and opening of an equalization valve whereby lift gas from the lower casing annulus is vented into the production tubing string.
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