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Wireline-Set Plugs and Packers
The PosiSet mechanical plug-back tool (MPBT) is used in rigless through-tubing recompletions. By using a mast or a crane, recompletions can be accomplished without the cost of a workover rig.
The PosiSet anchored elastomeric plug is run through tubing and set in casing to plug off fluid flow in the casing below the plug. The casing seal is similar to that produced by a cast-iron plug, but instead of an explosive charge, a downhole electric motor within the MPBT Setting Unit (MPSU) is used to contract the elastomer sealing assembly to form a firm seal against the casing wall. The expansion ratio is typically 3:1. An anchoring system keeps the tool in place while cement is placed on top of the plug to a height of 10 ft [3 m] or more to provide additional differential pressure.
The PosiSet plug is drillable. The smallest plug can withstand 25,000-lbf [111,205-N] force. The largest (95.8-in. [24.45-cm]) plug can withstand 90,000-lbf [400,340-N] force. If the wellbore pressure at setting depth is less than 1,000 psi [7 MPa], a special tool is used to aid the setting process of the PosiSet plug.
PosiSet plugs can be set in open hole, across perforations, and at gravel-pack screens.
The Positive Displacement Dump Bailer is used to place the required cement plug on top of the PosiSet plug. Release of a weight bar displaces cement from the bailer sections. The plug can be pressure tested 24 hr after the last bailer run, when the cement is at approximately 90% of its ultimate compressive strength. The temperature rating of the Positive Displacement Dump Bailer is 302°F [150°C].
The Casing Packer Setting Tool (CPST) provides a reliable method of deploying plugs and packers in the wellbore during completion, isolation, or abandonment. Schlumberger can also set most third party plugs and patches if supplied with appropriate adapter kits and tools.
Plugs
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