| 摘要 |
A downhole tool includes a mandrel 52 and a swellable packer 60 disposed on the mandrel 52 where the swellable packer 60 swells within a downhole annulus in the presence of an activating agent. An isolation element 70A, 70B is also disposed on the mandrel 52 adjacent the swellable packer 60 and is deformable radially outward to the borehole wall thus partially isolating the swellable packer 60 from a portion of the annulus. Bias units 90A, 90B may be releasably affixed on the tool adjacent the deformable elements 70A, 70B and can deform the elements. The bias unit 90A, 90B can be released either by swelling of the swellable element or by fluid pressure. Once released, the bias units 90A, 90B are axially biased toward the isolation elements 70A, 70B to deform them. In this way, the packer can form multiple seals with the borehole wall, and the isolation elements 70A, 70B can isolate the swellable element 60 from the downhole annulus.
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