Indexing Sleeve for Single-Trip, Multi-Stage Fracturing

A sliding sleeve (100) has a sensor (134) that detects plugs (150) (darts, balls, etc.) passing through the sleeves. A first insert (120) on the sleeve can be hydraulically activated by the fluid pressure in the surrounding annulus once a preset number of plugs have passed through the sleeve. Movement of this first insert activates a catch on a second insert. Once the next plug is deployed, the catch engages it so that fluid pressure applied against the seated plug through the tubing string can moves the second insert. Once moved, the insert reveals port in the housing communicating the sleeve's bore with the surrounding annulus so an adjacent wellbore interval can be stimulated. The first insert may also be hydraulically activated after a preset time after a plug has passed through the sleeve. Several sleeves can be used together in various arrangements to treat multiple intervals of a wellbore.