| 摘要 |
A small diameter stage cementer assembly 10 and a hydraulically operated packer collar stage cementer 110, including a cementer housing 12 for interconnection with a casing string 14 positionable in a slim-hole wellbore for a cementing operation. The cementer housing 12 including a seat 11 for receiving a lower, drillable portion 335 of an opening sleeve assembly 135 after the upper drillable portion 235 of the opening sleeve assembly 135 has been drilled out. The lower, drillable portion 335 wedges into engagement with the seat 11 to prevent rotation of the drillable portion 335 during drill-out, such that the lower portion 335 may be drilled up using a small diameter bit and drill string, and accommodating a reduced weight on bit. The packer collar embodiment includes a hydraulically actuatable packer 70. In the packer collar embodiment of the stage cementer 110, cementing ports 34 are provided separate in a separate axial plane from hydraulic inflation ports, such that the secondary opening device or rupture disks may be securely positioned within the cementing ports. Thereby, a relatively thin-walled outer case 20 may be utilized for the hydraulic passageway 130 to the packer 70, without having to increase the case outer diameter to accommodate positioning a rupture disk in the case. The stage cementer housing may be sized for use with a casing string 14 with a nominal OD of 4-½ inches or less. An improved method of operating a stage cementer is disclosed.
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