Patent EA-002250-B1 (EA)
Title: Method for formation of a plugin a petroleum well
Inventor: HANSEN HENNING
IPC: E21B/
Filed: 1999-05-04
Abstract: 1. A method for the formation of a plug (1) in a petroleum well (2) extending from the earth's surface or the sea floor to a petroleum reservoir, which well is lined with casing (3, 3'), comprising the following steps: a) forming at least one opening (4) in the casing (3) at a distance from the earth's surface, b) providing a liquid curable material is the opening (4) and an adjacent area of the well (2), which material after curing forms a plug (1) in the well, which method is characterised in that  - in step a) the opening (4) is formed by, a milling tool (12) which is driven by a hydraulic motor (22) which is energised by hydraulic fluid supplied through the coil tubing, jointed pipe or wireline (11), and which is anchored to the casing (3) by mechanical anchors (14), and - in step b) the material which is provided in the opening is a liquid curable resin. 2. A method according to claim 1, characterised in that a production tubing suing (5, 5') which is present in the well (2) prior to the formation of the plug (1) is cut (6) below the area of the plug (1), and that the production tubing string (5') above the cut (6) is lifted out of the well (2) while the production tubing string (5) below the cut (6) is left in the well (2). 3. A method according to claim 1 or 2, characterised in the milling tool (12) being suspended from coil tubing, jointed pipe or wireline (11). 4. A method according to claim 3, characterised in the opening (4) in the casing (3) being formed over a distance in the longitudinal direction of the well (2) by pulling the coil tubing (11) during operating the milling tool (12). 5. A method according to any of the preceding claims, characterised in the opening (4) in the casing (3) being formed in the entire circumference of the casing (3). 6. A method according to any of the preceding claims, characterised in that a mechanical or inflatable packer (15) is set right below the area of the opening (4) in the casing (3). 7. A method according to any of the preceding claims, characterised in that after step a) and prior to step b) a mechanical packer (15) is set in the opening (4) in the casing (3). 8. A method according to any of the preceding, claims, characterised in that step b) is carried out by: - forming a train of at least two fluid slugs in the well (2), one of the slugs being a liquid resin slug, - circulating the train of fluid slugs from the earth's surface, down into the well (2), through the opening (4) in the casing (3) and through an annulus (19) on the outside of the casing (3), back to the earth's surface, and  - stopping the circulation when the liquid resin slug is located in the area of the opening (4). 9. A method according to any of the claims 1-7, characterised in that step b) is carried out by: forming a train of at least two fluid slugs in coil tubing extending from the earth's surface to the area of the opening (4) in the casing (3), one of the slugs being a liquid resin slug, pumping the train of fluid slugs from the earth's surface to the area of the opening (4), and stopping the primping when the liquid resin slug is located in the area of the opening (4). 10. A method according to claims 8 or 9, characterised in isolating the liquid resin slug from the other fluid slugs by pistons or rubber plugs. 11. A method according to any of the preceding claims, characterised in that after the curing of the resin plug (1) a concrete plug (16) is formed on top of the resin plug (1). 12. A tool (9) for milling an opening (4) in a casing (3) of a petroleum well (2), which opening will at least partly be filled with a curable resin for the formation of a plug, characterised by comprising: - a stationary housing (17) which is anchored to the casing (3) by anchors (14) and suspended in the well (2) from coil tubing, jointed pipe or wireline (11), - a hydraulic motor (22) for creating rotary motion, energised by pressurised hydraulic fluid supplied from tie coil tubing, jointed pipe or wireline (11), the stationary part of the hydraulic motor (22) being rotationally secured to the housing (17), - a milling tool (12) for milling the opening (4) in the casing (3), the milling tool (12) being rotationally secured to the rotating part of the hydraulic motor (22) and slideable in the longitudinal direction of the well relative to the housing (17), - a transfer mechanism for transferring motion in the longitudinal direction of the well between the coil tubing, jointed pipe or wireline (11) and the milling tool (12), for forcing the milling tool (12) upwards in the well (2) by pulling the coil tubing (11). 13. A plug (1) for plugging casing (3) of a petroleum well (2), characterised by comprising a curable resin and a mechanical or inflatable packer (15), the mechanical or inflatable packer (15) being integrated with the resin by the curing of the resin.