CA2828241A1 - Eutectic salt abandonment plug for wellbores - Google Patents
Eutectic salt abandonment plug for wellbores Download PDFInfo
- Publication number
- CA2828241A1 CA2828241A1 CA 2828241 CA2828241A CA2828241A1 CA 2828241 A1 CA2828241 A1 CA 2828241A1 CA 2828241 CA2828241 CA 2828241 CA 2828241 A CA2828241 A CA 2828241A CA 2828241 A1 CA2828241 A1 CA 2828241A1
- Authority
- CA
- Canada
- Prior art keywords
- wellbore
- salt
- charge
- canister
- column
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 150000003839 salts Chemical class 0.000 title claims abstract description 49
- 230000005496 eutectics Effects 0.000 title claims abstract description 14
- 230000015572 biosynthetic process Effects 0.000 claims description 11
- 238000000034 method Methods 0.000 claims description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- 238000007599 discharging Methods 0.000 claims description 3
- 230000000149 penetrating effect Effects 0.000 claims description 3
- 230000003466 anti-cipated effect Effects 0.000 claims description 2
- 238000007789 sealing Methods 0.000 claims 1
- 239000007787 solid Substances 0.000 abstract description 2
- 239000007789 gas Substances 0.000 description 8
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 5
- 229910000831 Steel Inorganic materials 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 239000004568 cement Substances 0.000 description 3
- 239000012530 fluid Substances 0.000 description 3
- 238000004090 dissolution Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Chemical compound [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 description 2
- 230000003014 reinforcing effect Effects 0.000 description 2
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 235000010333 potassium nitrate Nutrition 0.000 description 1
- 239000004323 potassium nitrate Substances 0.000 description 1
- 235000010344 sodium nitrate Nutrition 0.000 description 1
- 239000004317 sodium nitrate Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/10—Sealing or packing boreholes or wells in the borehole
- E21B33/13—Methods or devices for cementing, for plugging holes, crevices or the like
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/10—Sealing or packing boreholes or wells in the borehole
- E21B33/13—Methods or devices for cementing, for plugging holes, crevices or the like
- E21B33/134—Bridging plugs
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Reciprocating Pumps (AREA)
Abstract
A charge of molten eutectic salt is lowered in an insulated canister to a depth in a well's wellbore where the temperature is sufficiently low to cause the salt to solidify. The charge is biased by a floating piston out of the canister using pressurized gas. A
controller actuates release of the gas at an appropriate time. The salt solidifies and expands radially within the wellbore and forms an immobilized solid column which closes and seals the wellbore. The assembly used can be positioned by wireline and its location in the wellbore can be tested within a short period of time.
controller actuates release of the gas at an appropriate time. The salt solidifies and expands radially within the wellbore and forms an immobilized solid column which closes and seals the wellbore. The assembly used can be positioned by wireline and its location in the wellbore can be tested within a short period of time.
Description
EUTECTIC SALT ABANDONMENT PLUG FOR WELLBORES
Field of the Invention The invention relates to an abandonment plug to be emplaced dowiihole in an oil or gas well wellbore for the purpose of closing it. It also relates to a method for putting the plug into place. It further relates to an abandonment plug assembly and to a salt plug component for use in the assembly.
Background When a cased well, such as a producing well or a "dry hole", is to be "abandoned", government regulations require the operator to close or seal the wellbore, so that downhole fluids are prevented from moving upwardly through it.
A conventional method for doing this usually involves:
= setting a mechanical bridge plug at a predetermined depth;
= pressure testing the effectiveness of the bridge plug hydrostatically;
= emplacing a column of cement, typically 8 meters in length, on top of the bridge plug, usually by circulating it into place or placement by means of a dump bailer apparatus; and = then "tagging" the top of the cement column after sufficient time has elapsed to allow it to solidify or "set up", to ensure it is solid and extends up to a desired elevation.
This procedure often involves the use of a service rig and crew for considerable time at significant expense. It further may be characterized by leakage over time due to shrinkage and cracking of the cement column.
It would be advantageous to provide a plug system wherein:
= the location and effectiveness of the plug can be tested shortly after setting the plug;
, , = the volume of material used is reduced; and = the system is adapted for use with wireline equipment.
It is the aim of the present invention to provide such a system.
Summary of the Invention The present invention is based on the concept of:
= supplying a charge of molten eutectic salt at a depth in a wellbore where the formation temperature is sufficiently low to cause the salt to solidify, in the course of which it expands radially and forms a solidified column which tightly engages the surrounding wellbore surface to immobilize or fix the column in place and seal across the wellbore;
= the salt column being protected against dissolution by the provision across each of its ends of radially extending seal elements which provide closure and seal against the wellbore surface to resist the ingress or entry of water into the salt column.
The sealed salt column finds application as a downhole bridging plug for use in the abandonment of oil and gas wells.
In one aspect, the invention is concerned with a downhole plug for use in the abandonment of an oil or gas well having casing whose inner surface defines the wellbore, comprising: a solidified eutectic salt column expanded radially into tight engagement with the casing surface so as to immobilize the column within the wellbore and seal across the wellbore.
In another aspect, the invention is concerned with a method for providing an abandonment plug in a well having a wellbore defined by casing and penetrating a downhole formation, comprising: conveying a molten charge of eutectic salt in a closed canister down the wellbore to a pre-determined depth at which the anticipated temperature of the formation is sufficiently low to cause the salt to solidify; and discharging the molten salt from the canister into a wellbore interval defined by axially spaced apart first and second seal elements which extend radially across the wellbore and seal against the casing; so that the discharged molten charge solidifies and expands radially to form a salt column tightly engaging the surrounding casing and immobilized in place and the seal elements function to resist ingress of water into the column.
In a further aspect, the invention is concerned with a salt pump unit for use as part of a well abandonment plug assembly at depth in a cased wellbore which penetrates a downhole formation comprising: a closed canister forming an internal chamber and containing a charge of molten eutectic salt operative to solidify when cooled to a relatively reduced temperature associated with the formation; a floating piston, positioned in the chamber at the upper end of the charge, for displacing the charge out of the chamber when said piston is biased downwardly therethrough; said canister having normally closed outlet means, operative when opened to enable discharge of the charge from the lower end of the canister; and inlet means at the upper end of the canister for admitting pressurized gas into the chamber to bias the piston downwardly so that it may displace the charge out of the chamber through the outlet means.
Description of the Drawings Figure 1 is a partly sectional side view of an abandonment plug assembly comprising, from the bottom up, a plug unit, a salt pump unit, and a salt plug actuator unit;
Figure 2 is a schematic side view of the plug unit, showing the end seals, mesh cylinder and fill tube;
Figure 3 is a schematic side view of the salt pump unit, showing the canister and piston;
Figure 4 is a schematic side view of the salt pump actuator unit, showing the vessel and timer / controller; and Figure 5 is a side view showing a fill tube and rupture disk used at the base of the canister.
Description of the Preferred Embodiment Having reference to the Figures, there is provided, from the bottom up, an abandonment plug assembly 1 of units operatively connected in series and comprising:
= a plug unit 2 having a bottom seal element 3, a mesh skeleton 4, a top seal element 5 and a fill tube 6 extending through the top seal element 5 into the mesh skeleton 4;
= a salt pump unit 7 for conveying a charge 8 of molten eutectic salt from ground surface through the wellbore 9 to a pre-determined depth and discharging the charge through the fill tube 6 into the mesh skeleton 4, the salt pump unit 7 comprising: a thermally insulated, closed canister 10 for containing the charge 8 and having an internal floating piston 11 for biasing the charge 8 through a normally closed rupture disk 12 into the fill tube 6; and = a salt pump actuator unit 13 comprising a hollow outer body 14 containing: a vessel 15 for containing pressurized nitrogen, the vessel 15 being connected to the upper end of the canister chamber 16 through a check valve 20, whereby the nitrogen, when released, may bias the floating piston 11 downwardly to rupture the disk 12 and displace the molten charge 8 through fill tube 6 into the mesh skeleton 4; and a timer /
controller 17 for opening the check valve 12 to initiate the eutectic salt column formation process at an appropriate time;
= the outer body 14 having a connector 18 at its upper end for disengagably connecting with a wireline 19 for lowering the assembly 1 into the wellbore 9.
Field of the Invention The invention relates to an abandonment plug to be emplaced dowiihole in an oil or gas well wellbore for the purpose of closing it. It also relates to a method for putting the plug into place. It further relates to an abandonment plug assembly and to a salt plug component for use in the assembly.
Background When a cased well, such as a producing well or a "dry hole", is to be "abandoned", government regulations require the operator to close or seal the wellbore, so that downhole fluids are prevented from moving upwardly through it.
A conventional method for doing this usually involves:
= setting a mechanical bridge plug at a predetermined depth;
= pressure testing the effectiveness of the bridge plug hydrostatically;
= emplacing a column of cement, typically 8 meters in length, on top of the bridge plug, usually by circulating it into place or placement by means of a dump bailer apparatus; and = then "tagging" the top of the cement column after sufficient time has elapsed to allow it to solidify or "set up", to ensure it is solid and extends up to a desired elevation.
This procedure often involves the use of a service rig and crew for considerable time at significant expense. It further may be characterized by leakage over time due to shrinkage and cracking of the cement column.
It would be advantageous to provide a plug system wherein:
= the location and effectiveness of the plug can be tested shortly after setting the plug;
, , = the volume of material used is reduced; and = the system is adapted for use with wireline equipment.
It is the aim of the present invention to provide such a system.
Summary of the Invention The present invention is based on the concept of:
= supplying a charge of molten eutectic salt at a depth in a wellbore where the formation temperature is sufficiently low to cause the salt to solidify, in the course of which it expands radially and forms a solidified column which tightly engages the surrounding wellbore surface to immobilize or fix the column in place and seal across the wellbore;
= the salt column being protected against dissolution by the provision across each of its ends of radially extending seal elements which provide closure and seal against the wellbore surface to resist the ingress or entry of water into the salt column.
The sealed salt column finds application as a downhole bridging plug for use in the abandonment of oil and gas wells.
In one aspect, the invention is concerned with a downhole plug for use in the abandonment of an oil or gas well having casing whose inner surface defines the wellbore, comprising: a solidified eutectic salt column expanded radially into tight engagement with the casing surface so as to immobilize the column within the wellbore and seal across the wellbore.
In another aspect, the invention is concerned with a method for providing an abandonment plug in a well having a wellbore defined by casing and penetrating a downhole formation, comprising: conveying a molten charge of eutectic salt in a closed canister down the wellbore to a pre-determined depth at which the anticipated temperature of the formation is sufficiently low to cause the salt to solidify; and discharging the molten salt from the canister into a wellbore interval defined by axially spaced apart first and second seal elements which extend radially across the wellbore and seal against the casing; so that the discharged molten charge solidifies and expands radially to form a salt column tightly engaging the surrounding casing and immobilized in place and the seal elements function to resist ingress of water into the column.
In a further aspect, the invention is concerned with a salt pump unit for use as part of a well abandonment plug assembly at depth in a cased wellbore which penetrates a downhole formation comprising: a closed canister forming an internal chamber and containing a charge of molten eutectic salt operative to solidify when cooled to a relatively reduced temperature associated with the formation; a floating piston, positioned in the chamber at the upper end of the charge, for displacing the charge out of the chamber when said piston is biased downwardly therethrough; said canister having normally closed outlet means, operative when opened to enable discharge of the charge from the lower end of the canister; and inlet means at the upper end of the canister for admitting pressurized gas into the chamber to bias the piston downwardly so that it may displace the charge out of the chamber through the outlet means.
Description of the Drawings Figure 1 is a partly sectional side view of an abandonment plug assembly comprising, from the bottom up, a plug unit, a salt pump unit, and a salt plug actuator unit;
Figure 2 is a schematic side view of the plug unit, showing the end seals, mesh cylinder and fill tube;
Figure 3 is a schematic side view of the salt pump unit, showing the canister and piston;
Figure 4 is a schematic side view of the salt pump actuator unit, showing the vessel and timer / controller; and Figure 5 is a side view showing a fill tube and rupture disk used at the base of the canister.
Description of the Preferred Embodiment Having reference to the Figures, there is provided, from the bottom up, an abandonment plug assembly 1 of units operatively connected in series and comprising:
= a plug unit 2 having a bottom seal element 3, a mesh skeleton 4, a top seal element 5 and a fill tube 6 extending through the top seal element 5 into the mesh skeleton 4;
= a salt pump unit 7 for conveying a charge 8 of molten eutectic salt from ground surface through the wellbore 9 to a pre-determined depth and discharging the charge through the fill tube 6 into the mesh skeleton 4, the salt pump unit 7 comprising: a thermally insulated, closed canister 10 for containing the charge 8 and having an internal floating piston 11 for biasing the charge 8 through a normally closed rupture disk 12 into the fill tube 6; and = a salt pump actuator unit 13 comprising a hollow outer body 14 containing: a vessel 15 for containing pressurized nitrogen, the vessel 15 being connected to the upper end of the canister chamber 16 through a check valve 20, whereby the nitrogen, when released, may bias the floating piston 11 downwardly to rupture the disk 12 and displace the molten charge 8 through fill tube 6 into the mesh skeleton 4; and a timer /
controller 17 for opening the check valve 12 to initiate the eutectic salt column formation process at an appropriate time;
= the outer body 14 having a connector 18 at its upper end for disengagably connecting with a wireline 19 for lowering the assembly 1 into the wellbore 9.
In greater detail, the plug unit 2 comprises a cylinder 21 of steel mesh 22 forming a skeleton 8 for receiving and reinforcing the charge 8 of molten eutectic salt 23, when it is discharged from the canister 10. The mesh cylinder 21 is sized to distribute and conduct the molten salt close to the inner surface 24 of the well casing 25.
The casing surface 24 defines the wellbore 9. As the relatively cool casing 25 and surrounding formation (not shown) function as a heat sink to remove heat from the salt, it solidifies and expands radially to tightly engage the casing surface 24 and thereby frictionally immobilize the resultant column 27 of solidified salt, which functions to close and seal across the wellbore 9.
At its lower and upper ends 40, 41 the mesh cylinder 21 is closed by seal elements 3, 5 respectively. Each seal element comprises a central steel disc 42 secured to the mesh 22 and serving as the mounting base for a stack of flexible seal skirts 43 formed of high temperature fabric coated with high temperature-tolerant silicone.
The salt pump unit 7 comprises a hollow, vacuum-insulated canister 10 which forms an internal chamber 16. The canister 10 is normally closed so as to contain the charge 8 of molten salt until the assembly 1 is activated. The canister 10 may be formed of steel and defines an insulated chamber. A floating piston 11 is positioned within the chamber 16, at the upper end of the salt charge 8. The piston 11 carries peripheral high temperature-resistant 0-rings 33 capable of withstanding the temperature of the molten salt.
The piston 11 further forms a central vent 34 for enabling displacement of water present in the skeleton 8 by molten salt entering it.
The upper end of the canister 10 is closed by an insulated threaded cap 35 having a port 36 for the admission of pressurized gas. The bottom end of the canister 10 is closed by a funnel-shaped element 37 sealed by a transverse rupture disk 12.
The salt pump actuator unit 13 comprises an outer container 14 enclosing a vessel 15 containing a charge 38 of pressurized nitrogen gas. A bottom outlet line 39 connects the vessel 15, through the wall 44 of the container 14 and canister cap 35, with the canister chamber 16. A normally closed solenoid valve 20 controls the discharge of gas through the outlet line 39. A conventional digital timer / controller 46, powered by a battery pack 47, is provided for opening the valve 20 at a pre-determined time which allows the assembly 1 to be positioned at the depth where the plug 2 is to be set.
OPERATION
The assembly 1 is suspended and lowered into the wellbore 9 by a wireline 19 attached to the connector 18. The flexible seal skirts 43 will flatten upwardly somewhat, allowing the assembly 1 to descend through fluid in the wellbore 9. During the lowering process, the mesh cylinder 21 will flood with wellbore fluid. Once the assembly 1 is at the prescribed depth it will be lifted slightly to open the seal skirts 43 into contact with the well casing 25.
The timer / controller 42 then signals the valve 20 to open, thereby admitting pressurized gas into canister chamber 16 through line 39. The gas drives the piston 11 downwardly, thereby rupturing the disk 12 and displacing the charge 8 of molten salt into the mesh cylinder 21. Alternatively, the valve signal may be sent via electronic wire line (e line) from surface.
By way of example, a typical charge 8 of molten eutectic salt 23 used could satisfy the following parameters for a wellbore cased with 4.5 "I.D. casing:
= volume ¨ 5 gallons = molten temperature ¨ 280 C
= solidification temperature rz: 260 C
= composition ¨ sodium nitrate and potassium nitrate mixture with steel mesh reinforcing = source ¨ Apco Industries Co. Ltd., Edmonton, Alberta.
Once the charge 8 of molten salt fills the mesh cylinder 21, it will begin to solidify and expand radially into tight engagement with the casing 25. When fully set, typically within minutes, the resultant column 27 of solidified salt is immobilized in the casing and seals across the wellbore 9.
It is contemplated that the tool described above could find application as a dissolvable packer for sequential fraccing operations. In this embodiment the top seal would be disengagable and retrieved with the salt injection assembly, allowing for the eventual dissolution of the plug by the frac water.
The casing surface 24 defines the wellbore 9. As the relatively cool casing 25 and surrounding formation (not shown) function as a heat sink to remove heat from the salt, it solidifies and expands radially to tightly engage the casing surface 24 and thereby frictionally immobilize the resultant column 27 of solidified salt, which functions to close and seal across the wellbore 9.
At its lower and upper ends 40, 41 the mesh cylinder 21 is closed by seal elements 3, 5 respectively. Each seal element comprises a central steel disc 42 secured to the mesh 22 and serving as the mounting base for a stack of flexible seal skirts 43 formed of high temperature fabric coated with high temperature-tolerant silicone.
The salt pump unit 7 comprises a hollow, vacuum-insulated canister 10 which forms an internal chamber 16. The canister 10 is normally closed so as to contain the charge 8 of molten salt until the assembly 1 is activated. The canister 10 may be formed of steel and defines an insulated chamber. A floating piston 11 is positioned within the chamber 16, at the upper end of the salt charge 8. The piston 11 carries peripheral high temperature-resistant 0-rings 33 capable of withstanding the temperature of the molten salt.
The piston 11 further forms a central vent 34 for enabling displacement of water present in the skeleton 8 by molten salt entering it.
The upper end of the canister 10 is closed by an insulated threaded cap 35 having a port 36 for the admission of pressurized gas. The bottom end of the canister 10 is closed by a funnel-shaped element 37 sealed by a transverse rupture disk 12.
The salt pump actuator unit 13 comprises an outer container 14 enclosing a vessel 15 containing a charge 38 of pressurized nitrogen gas. A bottom outlet line 39 connects the vessel 15, through the wall 44 of the container 14 and canister cap 35, with the canister chamber 16. A normally closed solenoid valve 20 controls the discharge of gas through the outlet line 39. A conventional digital timer / controller 46, powered by a battery pack 47, is provided for opening the valve 20 at a pre-determined time which allows the assembly 1 to be positioned at the depth where the plug 2 is to be set.
OPERATION
The assembly 1 is suspended and lowered into the wellbore 9 by a wireline 19 attached to the connector 18. The flexible seal skirts 43 will flatten upwardly somewhat, allowing the assembly 1 to descend through fluid in the wellbore 9. During the lowering process, the mesh cylinder 21 will flood with wellbore fluid. Once the assembly 1 is at the prescribed depth it will be lifted slightly to open the seal skirts 43 into contact with the well casing 25.
The timer / controller 42 then signals the valve 20 to open, thereby admitting pressurized gas into canister chamber 16 through line 39. The gas drives the piston 11 downwardly, thereby rupturing the disk 12 and displacing the charge 8 of molten salt into the mesh cylinder 21. Alternatively, the valve signal may be sent via electronic wire line (e line) from surface.
By way of example, a typical charge 8 of molten eutectic salt 23 used could satisfy the following parameters for a wellbore cased with 4.5 "I.D. casing:
= volume ¨ 5 gallons = molten temperature ¨ 280 C
= solidification temperature rz: 260 C
= composition ¨ sodium nitrate and potassium nitrate mixture with steel mesh reinforcing = source ¨ Apco Industries Co. Ltd., Edmonton, Alberta.
Once the charge 8 of molten salt fills the mesh cylinder 21, it will begin to solidify and expand radially into tight engagement with the casing 25. When fully set, typically within minutes, the resultant column 27 of solidified salt is immobilized in the casing and seals across the wellbore 9.
It is contemplated that the tool described above could find application as a dissolvable packer for sequential fraccing operations. In this embodiment the top seal would be disengagable and retrieved with the salt injection assembly, allowing for the eventual dissolution of the plug by the frac water.
Claims (4)
1. A downhole plug for use in the abandonment of an oil or gas well having casing whose inner surface defines the wellbore, comprising:
a solidified eutectic salt column expanded radially into tight engagement with the casing surface so as to immobilize the column within the wellbore and seal across the wellbore.
a solidified eutectic salt column expanded radially into tight engagement with the casing surface so as to immobilize the column within the wellbore and seal across the wellbore.
2. The plug as set forth in claim 1 comprising:
radially extending seal elements at each end of the column for sealing against the wellbore surface to resist the ingress of water into the column.
radially extending seal elements at each end of the column for sealing against the wellbore surface to resist the ingress of water into the column.
3. A method for providing an abandonment plug in a well having a wellbore defined by casing and penetrating a downhole formation, comprising:
conveying a molten charge of eutectic salt in a closed canister down the wellbore to a pre-determined depth at which the anticipated temperature of the formation is sufficiently low to cause the salt to solidify; and discharging the molten salt from the canister into a wellbore interval defined by axially spaced apart first and second seal elements which extend radially across the wellbore and seal against the casing;
so that the discharged molten charge solidifies and expands radially to form a salt column tightly engaging the surrounding casing and immobilized in place and the seal elements function to resist ingress of water into the column.
conveying a molten charge of eutectic salt in a closed canister down the wellbore to a pre-determined depth at which the anticipated temperature of the formation is sufficiently low to cause the salt to solidify; and discharging the molten salt from the canister into a wellbore interval defined by axially spaced apart first and second seal elements which extend radially across the wellbore and seal against the casing;
so that the discharged molten charge solidifies and expands radially to form a salt column tightly engaging the surrounding casing and immobilized in place and the seal elements function to resist ingress of water into the column.
4. A salt pump unit for use as part of a well abandonment plug assembly at depth in a cased wellbore penetrating a downhole formation comprising:
a closed canister forming an internal chamber and containing a charge of molten eutectic salt operative to solidify when cooled to a relatively reduced temperature associated with the formation;
a floating piston, positioned in the chamber at the upper end of the charge, for displacing the charge out of the chamber when said piston is biased downwardly therethrough;
said canister having normally closed outlet means, operative when opened to enable discharge of the charge from the lower end of the canister; and inlet means at the upper end of the canister for admitting pressurized gas into the chamber to bias the piston downwardly so that it may displace the charge out of the chamber through the outlet means.
a closed canister forming an internal chamber and containing a charge of molten eutectic salt operative to solidify when cooled to a relatively reduced temperature associated with the formation;
a floating piston, positioned in the chamber at the upper end of the charge, for displacing the charge out of the chamber when said piston is biased downwardly therethrough;
said canister having normally closed outlet means, operative when opened to enable discharge of the charge from the lower end of the canister; and inlet means at the upper end of the canister for admitting pressurized gas into the chamber to bias the piston downwardly so that it may displace the charge out of the chamber through the outlet means.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2828241 CA2828241A1 (en) | 2013-09-25 | 2013-09-25 | Eutectic salt abandonment plug for wellbores |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2828241 CA2828241A1 (en) | 2013-09-25 | 2013-09-25 | Eutectic salt abandonment plug for wellbores |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2828241A1 true CA2828241A1 (en) | 2015-03-25 |
Family
ID=52737513
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2828241 Abandoned CA2828241A1 (en) | 2013-09-25 | 2013-09-25 | Eutectic salt abandonment plug for wellbores |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2828241A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11371623B2 (en) | 2019-09-18 | 2022-06-28 | Saudi Arabian Oil Company | Mechanisms and methods for closure of a flow control device |
-
2013
- 2013-09-25 CA CA 2828241 patent/CA2828241A1/en not_active Abandoned
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11371623B2 (en) | 2019-09-18 | 2022-06-28 | Saudi Arabian Oil Company | Mechanisms and methods for closure of a flow control device |
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