| 摘要 |
<p>A casing centraliser (5) for centralising a casing (75) in a wellbore (85), at least a portion of the casing centraliser being plastic or ceramic, cermet or submicron grained cemented carbide. Various arrangements of raised portions (30) on the outermost surface (20) of the casing centraliser(s) (5) are described together with an arrangement of recesses (110) on the innermost surfaces (25).</p> |
