Packer Setting Dog Sub
Overview The Packer Setting Dog Sub is an integral part of a liner running string. It is used in setting a liner top Packer. The Dog Sub is placed in-between the Lift Nipple and the Running Tool. It has retractable Dogs which contract to allow it to enter the Tieback Receptacle (TBR). When the Packer is ready to be set, the Dog Sub is lifted out of the TBR. The spring-loaded Dogs release and move outward. When the work string is lowered, weight is set on the Dog Sub and the top of the TBR. It is this weight which is used to pack-off the Liner Top Packer.
- Once lifted out of the TBR, the Dogs permanently spring outward which prevents re-entry into the TBR which is allows weight to be set on the dogs to enable setting the packer
- Bearing design allows the workstring to be rotated while weight is being set down, this feature allows more weight to be downhole to properly set the packer
- The short length of the Dog Sub allows it to be as deep as possible in the TBR
- The design insures there are no loose Dogs by preventing them from falling out of their window once assembled