Eutectic alloy system for concentric casing string cement repair

Patent metadata

Field	Value
Publication number	US-12473797-B2
Application number	US-202418634840-A
Country	US
Kind code	B2
Filing date	Apr 12, 2024
Priority date	Apr 12, 2024
Publication date	Nov 18, 2025
Grant date	Nov 18, 2025

Abstract

A method of repairing wellbores includes setting a plug to isolate a wellbore flowpath within a plurality of concentric casing strings, milling a window through a radially innermost casing string of the plurality of concentric casing strings, via a casing milling tool, and radially outward towards one of a plurality of cement columns, cleaning out one of plurality of a cement columns between two of the concentric casing strings to expand the window radially, inserting a solid eutectic alloy into the wellbore flowpath above the plug, heating the solid eutectic alloy, via a heater inserted within the wellbore flowpath, to melt the eutectic alloy and allow the melted eutectic alloy to flow into the window, solidifying the melted eutectic alloy to form a solidified eutectic plug within the window, and drilling out the solidified eutectic plug to restore the wellbore flowpath through the eutectic plug.

First claim

The invention claimed is:

1 . A method comprising:
setting a plug to isolate a wellbore flowpath within a plurality of concentric casing strings; milling a window through a radially innermost casing string of the plurality of concentric casing strings, via a casing milling tool, and radially outward towards one of a plurality of cement columns; cleaning out the one of the plurality of cement columns between two of the concentric casing strings to expand the window radially; inserting a solid eutectic alloy into the wellbore flowpath above the plug; heating the solid eutectic alloy with a heater inserted within the wellbore flowpath and thereby melting the solid eutectic alloy and allowing a melted eutectic alloy to flow into the window; solidifying the melted eutectic alloy to form a solidified eutectic plug filling the window and wellbore flowpath; drilling out the solidified eutectic plug to restore the wellbore flowpath through the eutectic plug; releasing the plug from below the drilled solidified eutectic plug; and retracting the plug from the wellbore flowpath, wherein the plug is an expandable, releasable plug.

2 . The method of claim 1 , further comprising:
drilling through the solidified eutectic plug and into the plug to restore the wellbore flowpath, wherein the plug is a drillable plug.

3 . The method of claim 1 , further comprising:
running a production tubing through the restored wellbore flowpath.

4 . The method of claim 3 , further comprising:
setting a scab liner within the wellbore flowpath and axially spanning the window.

5 . The method of claim 1 , further comprising:
milling a casing string radially outwards of the radially innermost casing string to expand the window radially outwardly.

6 . The method of claim 5 , further comprising:
cleaning out a further one of the plurality of cement columns to further expand the window radially outwardly.

7 . The method of claim 1 , wherein inserting a solid eutectic alloy into the wellbore flowpath comprises inserting a plurality of eutectic alloy beads within the wellbore flowpath.

8 . A wellbore repair system, comprising:
a plurality of concentric casing strings disposed within a wellbore; a plurality of cement columns disposed radially outward of each of the concentric casing strings; a window defined radially through at least a radially innermost casing string of the one or more of the concentric casing strings and a radially innermost cement column of the plurality of cement columns; a plug set within an interior of the radially innermost casing string below the window; and a solidified eutectic alloy filling the window and a wellbore flowpath above the plug, wherein the solidified eutectic alloy forms a metal-to-metal seal with at least one of the concentric casing strings, and wherein the window includes a progressively stepped pattern through one or more of the plurality of cement columns disposed radially outward of the radially innermost casing string.

9 . The wellbore repair system of claim 8 , wherein the solid eutectic alloy comprises a bismuth-based alloy.

10 . The wellbore repair system of claim 8 , further comprising a flowpath extending through a portion of the solidified eutectic alloy.

11 . The wellbore repair system of claim 10 , wherein the plug is a drillable plug and a drill string is operable to restore the wellbore flowpath through the drillable plug.

12 . The wellbore repair system of claim 10 , further comprising a scab liner connected to an innermost casing string of the plurality of concentric casing strings and over the window to form a barrier between the leaks and the wellbore flowpath.

13 . The wellbore repair system of claim 8 , wherein the window further includes a progressively stepped pattern through one or more casing strings radially outwards of the radially innermost casing string.

14 . A wellbore repair system comprising:
a plurality of concentric casing strings disposed within a wellbore; a plurality of cement columns disposed radially outward of each of the concentric casing strings; a window defined radially through at least a radially innermost casing string of the one or more of the concentric casing strings and a radially innermost cement column of the plurality of cement columns; a plug set within an interior of the radially innermost casing string; a plurality of eutectic alloy beads inserted within the window above the plug; and a heater inserted within the wellbore and operable to melt the plurality of eutectic alloy beads, wherein the window includes a progressively stepped pattern through one or more of the plurality of cement columns disposed radially outward of the radially innermost casing string.

15 . The wellbore repair system of claim 14 , wherein the plurality of eutectic alloy beads comprises a bismuth-based alloy.

16 . The wellbore repair system of claim 14 , wherein the heater includes an electrically-operated heating element.

17 . The wellbore repair system of claim 14 , wherein the heater includes one or more reactive components operable to generate an exothermic reaction.

18 . The wellbore repair system of claim 14 , wherein the progressively stepped pattern of the window further extends through one or more casing strings disposed radially outwards of the radially innermost casing string.

Assignees

• Saudi Arabian Oil Co
• Wellbore Integrity Solutions

Inventors

• Al Marhoon Zahrah
• Alshaarawi Amjad
• Alkubaisi Abdallah A
• Alzaid Jafar S
• Mohamed Khalil E
• Heinold Thomas
• Egbe Peter
• Gallelli Alessandro Antonio
• Zhong Songlin
• Shearer David

Classifications

• E21B33/1204

  permanent; drillable · CPC title

• E21B29/06

  Cutting windows, e.g. directional window cutters for whipstock operations ({E21B29/005 and} E21B29/08 take precedence) · CPC title

• E21B29/02

  by explosives or by thermal or chemical means {(freeing stuck objects by explosives E21B31/002)} · CPC title

• E21B29/10

  Reconditioning of well casings, e.g. straightening · CPC title

• E21B33/1212

  including a metal-to-metal seal element · CPC title