Multiple position service seal unit with positive position indicating

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. Additionally, the positioning assembly provides partial restriction to longitudinal movement of a work string for activating the motion-compensating equipment of a floating service vessel so that ocean heave or swell does not cause excessive longitudinal excursions of a downhole service tool attached to a service string which is supported by the floating vessel.