Patent ID: 9745818
Date: 2017-08-29
CPC Classifications: E21B

Claim:
1. A swellable downhole apparatus comprising: a mandrel; and a swellable element on the mandrel, the swellable element comprising a material selected to increase in volume when exposed to a downhole stimulus and arranged on the mandrel to swell in a wellbore annulus to provide an annular barrier between the mandrel and a surrounding wall in a wellbore; and a radially contracting portion configured to reduce a diameter of a portion of the apparatus, forming a void for accommodating a volume of solid material displaced from the wellbore annulus by the swellable element when it swells to a swollen condition, wherein the radially contracting portion comprises one or more sacrificial materials, wherein the sacrificial materials comprise materials that undergo a phase change in the wellbore annulus, decreasing a volume of the sacrificial materials.