Subsurface lubricator and method of use
View Patent ↗A subsurface lubricator facilitates well completion, re-completion and workover while increasing safety and reducing expense. The subsurface lubricator includes a bi-directional packoff tool on its bottom end. Short hydraulic cylinders lubricate the subsurface lubricator into the well until the bi-directional packoff tool is in a top end of a casing of the well. High pressure fluid pumped through a side port of a wellhead of the well lubricates the subsurface lubricator into the well.
1. A subsurface lubricator for lubricating a long tool string into a cased wellbore, comprising:
a lubricator tube that houses the long tool string, the lubricator tube having a top end, a bottom end, an adaptor flange connected to the top end and an injector plate connected to the adaptor flange;
a bidirectional packoff tool connected to the bottom end, the bidirectional packoff tool comprising an upper sealing element that traps pressurized fluid injected into an annulus between a casing of the cased wellbore and the lubricator tube, and a lower sealing element between the upper sealing element and a bottom end of the bidirectional packoff tool, the lower sealing element isolating a wellhead of the cased wellbore from fluid pressure in the cased wellbore below the bottom end of the bidirectional packoff tool; and
an anchor plate for anchoring the subsurface lubricator to the wellhead of the cased wellbore.
2. The subsurface lubricator as claimed in claim 1 wherein the anchor plate comprises;
a central passage through which the lubricator tube reciprocates;
an anchor pin surrounding the central passage, the anchor pin including a pin thread on an outer periphery thereof;
a packing cavity within the central passage, the packing cavity receiving high pressure packing that provides a high pressure fluid seal around the lubricator tube; and
connection points for hydraulic cylinders to lubricate the lubricator tube through the wellhead until the bidirectional packoff tool is located in a top of the casing of the cased wellbore and pressurized fluid can be supplied through a port of the wellhead to lubricate the lubricator tube further into the casing by applying fluid pressure to the upper sealing element of the bidirectional packoff tool.
3. The subsurface lubricator as claimed in claim 1 wherein the adaptor flange supports equipment for controlling the long tool string.
4. The subsurface lubricator as claimed in claim 1 wherein the bidirectional packoff tool comprises a first cup tool mandrel that slidably supports a first elastomeric cup having an upwardly oriented open end that packs off in the casing to provide fluid pressure isolation above the bidirectional packoff tool, and a second cup tool mandrel that slidably supports a second elastomeric cup having a downwardly oriented open end that packs off in the casing to isolate the wellhead of the cased wellbore from the fluid pressure below the bottom end of the bidirectional packoff tool.
5. The subsurface lubricator as claimed in claim 1 wherein the bidirectional packoff tool comprises a cup tool mandrel connected to a casing packer, the cup tool mandrel slidably supporting an upwardly oriented elastomeric cup, and the lower sealing element comprises the casing packer which packs off in the casing to isolate the wellhead from the fluid pressure below the bottom end of the bidirectional packoff tool.
6. The subsurface lubricator as claimed in claim 5 wherein the casing packer further comprises casing-engaging slips that releasably lock the lubricator tube in the casing.
7. The subsurface lubricator as claimed in claim 2 comprising connection points for at least two hydraulic cylinders.
8. The subsurface lubricator as claimed in claim 7 further comprising at least two extension rods for connecting cylinder rods of the at least two hydraulic cylinders to the injector plate.
9. A subsurface lubricator for lubricating a long tool string into a cased wellbore, comprising:
a lubricator tube for housing the long tool string, the lubricator tube having a top end and a bottom end;
a bidirectional packoff tool connected to the bottom end and having an upper sealing element with an open end oriented towards the top end of the lubricator tube and a lower sealing element below the upper sealing element to isolate a wellhead of the cased wellbore from fluid pressure in the cased wellbore below the bidirectional packoff tool;
an anchor plate for mounting the lubricator tube to the wellhead; and
hydraulic cylinders for lubricating the lubricator tube through the wellhead of the cased wellbore until the bidirectional packoff tool is in a top of a casing of the cased wellbore and pressurized fluid can be supplied through a port of the wellhead to an annulus above the bidirectional packoff tool to lubricate the lubricator tube downwards into the casing.
10. The subsurface lubricator as claimed in claim 9 wherein the anchor plate comprises:
a central passage through which the lubricator tube reciprocates with a packing cavity surrounding the lubricator tube that accepts high pressure packing; and
connection points for the hydraulic cylinders.
11. The subsurface lubricator as claimed in claim 9 further comprising a lubricator tube adaptor connected to the top end of the lubricator tube, the lubricator tube adaptor comprising:
a flange for supporting equipment that suspends the downhole tubing string;
an annular shoulder that rotatably supports an anchor nut which locks the lubricator tube to the anchor plate; and
an injector plate having connection points for the hydraulic cylinders.
12. The subsurface lubricator as claimed in claim 9 wherein the bi-directional packoff tool comprises first and second interconnected cup tool mandrels, the first cup tool mandrel supporting an upwardly oriented elastomeric cup that traps the pressurized fluid injected into the annulus, and the second cup tool mandrel supporting a downwardly oriented elastomeric cup that isolates the wellhead from the fluid pressure in the cased wellbore.
13. The subsurface lubricator as claimed in claim 9 wherein the lubricator tube comprises a plurality of lubricator joints connected end-to-end to provide a lubricator tube having smooth cylindrical inner and outer surfaces.
14. A method of lubricating a downhole tool string into a cased wellbore, comprising:
mounting a subsurface lubricator with a lubricator tube to a top end of a pressure control gate mounted to a wellhead of the cased wellbore, the lubricator tube having a top end with an adaptor flange and a bottom end connected to a bidirectional packoff tool, the lubricator tube housing the downhole tool string that is lowered from the lubricator tube through the bidirectional packoff tool into the cased wellbore after the lubricator tube is lubricated into a casing of the cased wellbore;
opening the pressure control gate and lubricating the lubricator tube through the wellhead until the bidirectional packoff tool is located in a top of a casing of the cased wellbore; and
injecting pressurized fluid through the wellhead into an annulus above the bidirectional packoff tool to lubricate the lubricator tube downwardly into the casing.
15. The method as claimed in claim 14 further comprising anchoring the lubricator tube to an anchor plate of the subsurface lubricator using an anchor nut rotatably supported by a lubricator tube adaptor connected to the top end of the lubricator tube, after the lubricator tube has been lubricated into the casing.
16. The method as claimed in claim 14 further comprising operating hydraulic cylinders to lubricate the lubricator tube through the wellhead until the bidirectional packoff tool is located in the top of the casing.
17. The method as claimed in claim 16 wherein operating the hydraulic cylinders comprises connecting cylinder rods of the hydraulic cylinders to an injector plate connected to the top end of the lubricator tube using extension rods connected between cylinder rod ends of the cylinder rods and the injector plate to lubricate the lubricator tube through the wellhead.
18. The method as claimed in claim 14 further comprising lubricating the lubricator tube out of the wellhead after using the downhole tool string to perform downhole operations.
19. The method as claimed in claim 18 wherein lubricating the lubricator tube out of the wellhead comprises connecting a drain line to a side port of the wellhead and opening a valve of the side port to release pressurized fluid from the annulus.
20. The method as claimed in claim 19 further comprising:
closing the valve of the side port and connecting hydraulic cylinders to an injector plate connected to the top end of the lubricator tube;
opening the valve of the side port and operating the hydraulic cylinders to lubricate the lubricator tube out of the wellhead until the bidirectional packoff tool is just below the side port;
draining the pressurized fluid from the wellhead;
closing the valve of the side port and lubricating the lubricator tube out of the wellhead using the hydraulic cylinders;
closing the pressure control gate mounted to the wellhead; and
removing the subsurface lubricator from the wellhead.