Abstract: An annular safety system for a well produced by gas lift includes a packer, a landing nipple below the packer and an operating seal unit to which primary and secondary well tubings and a control line are connected. There is an inline valve in the secondary tubing and safety valve operated by the control line in a primary flow conduit in the operating seal unit. After the operating seal unit is inserted through the packer to automatically land and be locked in the landing nipple and the packer operated to anchor and seal in a well casing, flow passages are formed for conveying lift gas from the secondary tubing to around the landing nipple for lifted flow upward through the primary conduit and tubing. When the well is being produced by lift gas, and pressure in the control line is reduced purposely or by rupture of the control line, the safety valve operates to prevent upward lifted flow in the primary tubing.

Abstract: A production sub carrying a plurality of annular locator rings is coupled in series relation with downhole production equipment. A collet latch assembly including fixed and floating collet members is connected to a down hole service tool and is inserted into releasable coupling engagement with the annular locator rings of the production sub. Resilient finger portions of the fixed collet are alternately supported and unsupported by the floating collet to establish positive engagement with a selected one of the annular locator rings or to permit passage of the latch assembly with respect to the locator ring. The foregoing arrangement provides positive restriction to longitudinal movement of a work string which allows a downhole service tool attached to the work string to be selectively positioned at predetermined operating locations relative to downhole equipment.

Abstract: A production sub carrying a plurality of annular locator rings is coupled in series relation with downhole production equipment. A collet latch assembly including fixed and floating collet members is connected to a down hole service tool and is inserted into releasable coupling engagement with the annular locator rings of the production sub. Resilient finger portions of the fixed collet are alternately supported and unsupported by the floating collet to establish positive engagement with a selected one of the annular locator rings or to permit passage of the latch assembly with respect to the locator ring. The foregoing arrangement provides positive restriction to longitudinal movement of a work string which allows a downhole service tool attached to the work string to be selectively positioned at predetermined operating locations relative to downhole equipment.