Removable treating plug with run in protected agglomerated granular sealing element
View Patent ↗A fully disintegrating plug has a passage therethrough and a ball seat at an upper end. The seal material that comprises plastic nuggets, sand and a grease binder is initially disposed behind a protective sleeve. A wireline setting tool creates relative movement between a plunger and a mandrel body that has a ramp surface adjacent the outlet of the protective sleeve. The sleeve outlet is closed for running in but plunger movement pushes the seal material so as to displace the closure at the sleeve outlet with the seal material that is forced up the mandrel ramp surface and against the surrounding tubular. After an object is landed on the mandrel seat and the treating is concluded, the plug components are caused to disintegrate or otherwise fail for complete removal. Multiple plugs are contemplated for fracturing or other treating applications.
1. A disintegrating plug for subterranean use in a borehole defined by a borehole wall, comprising:
a mandrel having a selectively closed passage therethrough;
a sealing mixture initially disposed in a cavity defined by said mandrel said cavity having a selectively sealed outlet;
a plunger selectively movable with respect to said mandrel to push said sealing mixture out of said cavity and into an annular gap between said mandrel and the surrounding borehole wall; and
said mandrel comprises an external ramp adjacent said selectively sealed outlet that changes the dimension of said annular gap.
2. The plug of claim 1 , wherein:
said selectively sealed outlet is sealed with a material removed by movement of said sealing mixture due to movement of said plunger.
3. The plug of claim 1 , wherein:
said selectively sealed outlet is sealed initially with an adhesive or a dissolvable polymer.
4. The plug of claim 1 , wherein:
said mandrel and said plunger are made of a disintegrating material.
5. The plug of claim 1 , wherein:
said plunger applies an axial force on said sealing mixture that is translated to a radial force on said sealing mixture by an adjacent ramp on said mandrel.
6. The plug of claim 1 , wherein:
said sealing mixture is at least in part a granular material.
7. The plug of claim 6 , wherein:
aid sealing mixture contains grease.
8. The plug of claim 1 , wherein:
said sealing mixture contains granular particles of different sizes.
9. The plug of claim 8 , wherein:
at least some of said granular particles comprise sand.
10. The plug of claim 1 , wherein:
said sealing mixture contains pellets or chalk.
11. The plug of claim 10 , wherein:
said pellets are made of controlled electrolytic material or a dissolvable polymer.
12. The plug of claim 1 , wherein:
said outlet has a barrier that is removed with exposure to well fluids.
13. The plug of claim 1 , wherein:
said sealing mixture is protected from impact during running in by said mandrel.
14. The plug of claim 1 , wherein:
said sealing mixture is exclusively retained for running in by said mandrel cavity and said selectively sealed outlet.
15. A method of setting a removable plug for subterranean isolation, comprising:
locating a sealing mixture in a mandrel cavity;
selectively retaining said sealing mixture in said cavity;
forcing the sealing mixture from said cavity and against said mandrel and a surrounding borehole wall that define a tapering gap;
performing a subterranean operation after said forcing;
disintegrating said mandrel after said performing to release the sealing mixture from the surrounding borehole wall to break up for dropping in the borehole or for removal by circulation or reverse circulation;
leaving no part of the removable plug at the location where said plug was set after said disintegrating.
16. The method of claim 15 , comprising:
using a cone on said mandrel and a plunger on said mandrel for said forcing.
17. The method of claim 16 , comprising:
making said cone and plunger from a disintegrating material;
performing said selectively retaining with a material that is forced out by movement of said sealing mixture or by exposure of said material to well fluids.
18. The method of claim 15 , comprising:
providing granular materials of different sizes mixed with grease as said sealing mixture.
19. The method of claim 18 , comprising:
using disintegrating pellets made of a controlled electrolytic material or dissolvable polymer as one of said granular materials and sand as another of said granular materials.
20. The method of claim 15 , comprising:
treating a formation by at least one of fracturing, acidizing, or stimulating.
21. A method of using the plug in claim 1 for a subterranean treating a formation by at least one of fracturing, acidizing, or stimulating, comprising
setting the plug in a borehole;
performing fracturing, acidizing, or stimulating against the plug.