Plug and abandon with fusible alloy seal
A method of creating a seal in a tubular by melting a first component comprising a fusible alloy, using heat produced by an exothermic, hydrolysis reaction of a second component comprising a metal, to provide a melted fusible alloy, and allowing the melted fusible alloy to solidify in the tubular, wherein the fusible alloy expands upon solidifying and forms the seal. A system for carrying out the method is also provided.
1 . A method of zonal isolation in a wellbore, the method comprising:
forming a seal at a location in a tubular by:
heating at least one material comprising a hypo-eutectic or a hyper-eutectic to provide a melted material, wherein heating comprises reacting a metal via an exothermic reaction and transferring heat produced by the exothermic reaction to the at least one material; and
solidifying the melted material at the location in the tubular to form the seal, wherein the melted material expands upon solidifying, and wherein the seal plugs the wellbore for plug and abandon; and
prior to the heating, placing into the tubular a wellbore tool comprising: a pressure vessel containing the at least one material, the metal, and a concentrated acid or base, a first barrier between the concentrated acid or base and the exterior of the pressure vessel, and a second barrier between the metal and the concentrated acid or base, and comprising a first activation component configured to, when activated, cause failure of the first barrier, whereby water enters the pressure vessel and combines with the concentrated acid or base to provide a diluted aqueous acid or base, and a second activation component configured to, when activated, cause failure of the second barrier, whereby the diluted aqueous acid or base contacts the metal to initiate an exothermic reaction and heat from the exothermic reaction melts the at least one material to provide the melted material.
2 . The method of claim 1 , wherein the exothermic reaction comprises hydrolysis of the metal via the equation:
X
(
s
)
+
2
H
2
O
(
l
)
→
X
(
OH
)
2
(
g
or
s
)
+
H
2
(
g
)
,
(
1
)
wherein X comprises the metal.
3 . The method of claim 1 , wherein the material comprises a hypo-eutectic comprising a major component and a minor component, wherein the minor component is present in an amount less than an amount of the minor component in a eutectic mixture of the major component and the minor component.
4 . The method of claim 1 , wherein the material comprises a hyper-eutectic comprising a major component and a minor component, wherein the minor component is present in an amount greater than an amount of the minor component in a eutectic mixture of the major component and the minor component.
5 . The method of claim 1 , wherein the metal comprises magnesium (Mg).
6 . The method of claim 1 , further comprising prior to heating the material, incorporating a magnetic component in the material to make it a magnetorheological material.
7 . The method of claim 1 , wherein the wellbore tool further comprises heat transfer vanes, fins, or other heat transfer structures between the metal and the and the at least one material, to enhance heat transfer from the heat produced by the exothermic, hydrolysis reaction to the at least one material.
8 . The method of claim 1 , wherein the wellbore tool further comprises a plurality of fins, wipers, whiskers, cups, or another flow barrier that extend from a top of the tool to the tubular, and restrict axial flow of fluid within the tubular.
9 . The method of claim 1 , wherein the metal is positioned proximal a central axis of the pressure vessel relative to the at least one material.
10 . The method of claim 1 , wherein the at least one material includes a first material and a second material, wherein the first material comprises a first fusible alloy, wherein the second material comprises a second fusible alloy, wherein the first material has a first material melting temperature and the second material has a second material melting temperature, and wherein the first material melting temperature is greater than or less than the second material melting temperature, wherein the metal, the first material, and the second material are concentrically disposed about a central axis of the pressure vessel, and:
wherein the metal is positioned proximal the central axis of the pressure vessel, wherein the first material is adjacent to and surrounds the metal, and wherein the second material is adjacent to and surrounds the first material; or
wherein the second material is positioned proximal the central axis of the pressure vessel, wherein the first material is adjacent to and surrounds the second material, and wherein the metal is adjacent to and surrounds the first material, distal the central axis relative to the first material and the second material.
11 . The method of claim 1 , wherein the acid comprises hydrochloric acid, citric acid, acetic acid, formic acid, hydrofluoric acid, carbonic acid, or a combination thereof.
12 . The method of claim 1 , wherein the first activation component, the second activation component, or both comprise a rupture disk designed to rupture at a pressure, a device that creates a hole in the barrier when activated by an uphole above ground or downhole trigger or timer, a dissolving plug, a mandrel with a port that opens at a design pressure, a pressure sensor, a trigger valve, a wireless receiver, a wired trigger, or a combination thereof.
13 . The method of claim 1 , wherein at least one material further comprises an inert material with a heat capacity of greater than about 2 MJ/(Km 3 ), a non-phase-expanding fusible alloy, and/or heat transfer fins distributed throughout to transfer heat from the hydrolysis reaction to the first material, the second material, or both, respectively.
14 . The method of claim 1 , wherein the at least one material comprises a multi-melt fusible alloy comprising a first material having a first material melting temperature and a second material having a second material melting temperature, wherein the first material melting temperature is greater than or less than the second material melting temperature.
15 . The method of claim 1 , further comprising positioning the melted material at a location within the tubular by utilizing a flow barrier in the tubular to direct the melted material to the location, maintain the melted material at the location, or both.
16 . The method of claim 15 further comprising positioning the flow barrier at the location in the tubular, wherein the flow barrier restricts flow of the melted material during the solidifying.
17 . The method of claim 1 , wherein the at least one material comprises a magnetorheological material, and wherein the method further comprises positioning the melted material at a location within the tubular by employing a magnet within the tubular to direct the melted material to the location, maintain the melted material at the location, or both.
18 . The method of claim 17 , wherein the magnetorheological material comprises the a hypo-eutectic or hyper-eutectic combined with iron particles that are acicular, cylindrical, elliptical, or a combination thereof.
19 . The method of claim 1 , wherein the first activation component; and the second activation component each comprise a rupture disk designed to rupture at a design pressure.
20 . The method of claim 19 , wherein the metal comprises magnesium, and wherein the tool is a wireline or slickline tool.