| 摘要 |
<p>A downhole apparatus, for example a centraliser, comprises a swellable material which expands upon contact with at least one predetermined fluid. In a first aspect of the invention, a centraliser comprises a body and a plurality of formations upstanding from the body. In another aspect, a downhole apparatus comprise a throughbore configured to receive a tubular, a swellable member, and a rigid assembly integrally formed with the swellable member. The rigid assembly provides stand off to the apparatus in use. In a further aspect, the downhole apparatus has a first condition, before expansion of the swellable member in which a rigid assembly defines a maximum outer diameter of the apparatus. In a second condition after expansion of the swellable member, the swellable member defines a maximum outer diameter of the apparatus. In a preferred embodiment the rigid assembly is designed to flex or deform under an axial or radial load.</p> |
