| 摘要 |
A method and apparatus for cementing a zone of borehole casing using an external casing packer (ECP). The method involves sealing the base of the ECP with a ball dropped in a seat, and then pressurising the casing to inflate an elastomeric packer sleeve through a one-way valve. When a design differential pressure is reached across the casing and elastomeric sleeve, a grout valve In the upper part of the packer opens to limit the sleeve inflation pressure and to provide a one-way valve through which cement grout passes to permit grouting of the annul?s between the casing and the borehole.
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