¶ Packer
Once a Tubing string has been defined, the Production Packer button becomes available. Pressing the Production Packer button opens the Packer window:
¶ Installation parameters and functional limits
- Free
- Down Limited
- Fixed
For all packer types, there are two required inputs at the top of the window: the Packer Setting Depth and the Packer Bore ID. The default values are based on the current wellbore configuration.
¶ Free Packer
Selecting the Free packer type requires no further inputs. The underlying assumption for this packer type is that the packer seals are completely free to move up or down in response to changes from the Initial Condition. Therefore, no loads resulting from changes relative to the Initial Condition are transferred from the tubing through the packer to the casing.
¶ Down Limited Packer
Selecting the Down Limited packer type makes the Limits inputs available. With the Down Limited configuration, the well designer can select where the packer seals are positioned within the seal bore and, if desired, the tubing can be landed with a slack-off force. If the seals are positioned such that they cannot travel downward, then any further change resulting in a tendency to move the seals downward will manifest itself as a downward force exerted by the tubing, through the packer to the casing. A change resulting in a tendency to move the seals upward will first manifest itself as a reduction of the downward force until the force goes to zero, then the seals will begin to move upward in the seal bore.
¶ Fixed Packer
Selecting the Fixed packer type makes the Activation inputs available. Here the well designer can select whether the packer is to be mechanically, hydrostatically, or hydraulically set. The underlying assumption for this packer type is that the packer seals are completely fixed. They are not allowed to move up or down in response to changes from the Initial Condition. Therefore, all the loads resulting from changes relative to the Initial Condition are transferred from the tubing through the packer to the casing.
For mechanically set fixed packers, the initial condition includes the mechanical (pick-up or slack-off) force applied when setting the packer. For hydraulically set packers, the initial condition includes the resulting force applied when annulus pressure is applied to set the packer.
For hydrostatically set packers, the initial condition includes the given activation pressure, applied inside and outside the tubing.