| 摘要 |
<p>A small diameter stage cementer assembly (10) and a hydraulically operated packer collar stage cementer (110), comprise 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) maybe 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 4-1/2 inches or less. <IMAGE></p> |
