| 摘要 |
<p>The present invention provides a wellhead securement arrangement including a first inner casing string 32 which is held in axial loading and a second inner casing string 56 which is also held in axial loading. Both of the first and second inner casing strings 32, 56 are releasably clamped such that the casing strings 32, 56 cannot move in an upwards or a downwards longitudinal direction. Prior to being clamped in such a position, the wellhead securement arrangement provides first retaining means to retain the first and second casing strings in cementing position whereby "cement returns" are able to flow around the respective hangers 36, 58 and upward through a casing towards the surface. Once cemented, the upper hangers 36, 58 of the respective inner casing strings 32, 56 are moved upwardly where the hanger 36, 58 is then clamped in position to maintain the respective inner casing string 32, 56 under an axial load whilst being prevented from moving either upwardly or downwardly.</p> |
