SEAT ASSEMBLY WITH COUNTER FOR ISOLATING FRACTURE ZONES IN A WELL

摘要

A specially designed rotary indexing system and associated operational methods are incorporated in a downhole control device, representatively a sliding sleeve valve, having an outer tubular member in which an annular plug seat is coaxially disposed. The plug seat is resiliently expandable between a first diameter and a larger second diameter and is illustratively of a circumferentially segmented construction. The rotary indexing system is operative to detect the number of plug members that pass through and diametrically expand the plug seat, and responsively preclude passage of further plug members therethrough when such number reaches a predetermined magnitude. Such predetermined magnitude is correlated to the total rotation of an indexing system counter ring portion rotationally driven by axial camming forces transmitted to the rotary indexing system by successive plug member passage-generated diametrical expansions of the plug seat.

主权项

1. A control apparatus operably positionable in a wellbore, comprising:
a tubular member extending along an axis; an annular seat structure coaxially supported within the tubular member and being diametrically expandable by a plug member passing axially therethrough from a first diameter small enough to block passage of the plug member through the annular seat structure to a second diameter permitting the plug member to pass through the annular seat structure, and then being contractible to the first diameter; and a counter apparatus operative to lock the annular seat structure at the first diameter in response to a predetermined number of plug members having passed through and diametrically expanding the annular seat structure to the second diameter, the counter apparatus including:
a first portion rotationally indexable about the axis;a second portion operative, in response to a diametric expansion of the annular seat structure to the second diameter, to engage and rotationally index the first portion through a predetermined angle about the axis; anda third portion separated from the first portion by an axially extending separator that separates and prevents one of the first and third portions from displacing toward the other of the first and third portions,one of the first and third portions having a separator receiver that receives the axially extending separator when the separator receiver aligns with the axially extending separator in a manner that one of the first and third portions displaces towards the other of the first and third portions and lock the annular seat structure at the first diameter.