Patent ID: 7870909

Claim:
A method of providing zonal isolation in a wellbore completion having multiple formation zones, the method comprising the steps of: identifying, before completing a wellbore, a first anticipated zone and a second anticipated zone to be isolated from other formation zones in the wellbore after the wellbore is placed on production; selecting, before completing the wellbore, a completion assembly adapted for accepting a first deployable isolation assembly for isolating the first anticipated zone for isolation after completion of the wellbore and after placing the wellbore on production; providing the first deployable isolation device for the selected completion assembly, the first deployable isolation device having a mandrel having an internal bore and a swellable material disposed on the exterior of the mandrel, wherein the swellable material extends a length sufficient to seal across the first anticipated zone, the first deployable device further comprising a connector adapted for mating with a second deployable isolation device; providing a second deployable isolation device having an anchoring device adapted for mating with the connector of the first deployable isolation device and a swellable material extending a length sufficient to seal across the second anticipated zone when stacked atop the first deployable isolation device; completing the wellbore with the selected completion assembly; positioning, after the wellbore is placed on production, the first deployable isolation assembly in the selected completion system adjacent to the first anticipated zone with the swellable material extending the length of the first anticipated zone; sealing flow from the first anticipated zone at the interior of the selected completion assembly when the wellbore is on production in response to the swellable material of the first deployable isolation device expanding outward from the mandrel to the completion assembly forming an annular seal across the length of the first anticipated zone; stacking, later in the production life, the second deployable isolation device atop the first isolation device thereby positioning the respective swellable material across the length of the second anticipated zone; and sealing flow from the second anticipated zone in response to the swellable material of the second deployable isolation device expanding.