| 摘要 |
<p>This invention relates to an improved method of cementing casing in a well where the casing string will subsequently be heated by the injection of steam or the flowing of other hot fluids through the casing. Long vertical anchor bars are positioned about the lower portion of the casing string. Lower holding means retains the lower ends against the casing string. Likewise, upper holding means holds the upper end against the casing. Means are provided for releasing the upper holding means and for forcing the upper ends of the anchor bars outwardly so that they engage and anchor against the borehole wall. Prior to the anchoring of the anchor bars, cement is circulated down through the casing string and up the annulus between the casing and the borehole wall, and during this time the casing can be rotated or moved up and down in accordance with good casing cementing practice. After the cement has all been circulated into the casing-well annulus, the anchors are set and the casing is pulled upwardly under tension and is held under tension until the cement sets.</p> |
