Dissolvable isolation devices with an altered surface that delays dissolution of the devices

Patent metadata

Field	Value
Publication number	US-10125565-B2
Application number	US-201414655039-A
Country	US
Kind code	B2
Filing date	Jun 23, 2014
Priority date	Jun 23, 2014
Publication date	Nov 13, 2018
Grant date	Nov 13, 2018

Abstract

A wellbore isolation device comprising: a material that dissolves via corrosion when in contact with a wellbore fluid, a surface of the material, wherein the surface of the material is altered via a surface treatment, and wherein the altered surface delays corrosion of the material for a desired amount of time. A method of removing the wellbore isolation device comprising: contacting or allowing the wellbore isolation device to come in contact with a wellbore fluid; and causing or allowing at least the portion of the material to dissolve.

First claim

What is claimed is:

1. A method of removing a wellbore isolation device comprising:
contacting or allowing the wellbore isolation device to come in contact with a wellbore fluid,
wherein at least a portion of the wellbore isolation device comprises a material that dissolves via corrosion when in contact with the wellbore fluid,
wherein the surface of the portion of the isolation device is altered via a surface treatment that modifies the composition of a treated portion of the isolation device to create an altered surface, wherein the altered surface delays corrosion of at least a portion of the material for a desired amount of time, wherein the altered surface is a layer that contains pores, wherein the wellbore isolation device further comprises a sealant placed over the altered surface, wherein the sealant fills the pores; and

causing or allowing at least the portion of the material to dissolve,
wherein the material is a metal alloy, wherein the metal alloy undergoes galvanic corrosion in the presence of an electrolyte without a distinct cathode being present,
wherein the metal alloy comprises magnesium as the metal, and
wherein the magnesium is in a concentration of at least 85% by volume of the metal alloy.

2. The method according to claim 1 , wherein the wellbore fluid is selected from the group consisting of, solutions of an acid, a base, a salt, and combinations thereof.

3. The method according to claim 1 , wherein the isolation device is capable of restricting or preventing fluid flow between a first wellbore interval and a second wellbore interval.

4. The method according to claim 1 , wherein isolation device is a ball, a ball seat, a plug, a bridge plug, a wiper plug, a frac plug, a packer, or a plug for a base pipe.

5. The method according to claim 1 , wherein the portion of the isolation device is the mandrel of a packer or plug, a spacer ring, a slip, a wedge, a retainer ring, an extrusion limiter or backup shoe, a mule shoe, a ball, a flapper, a ball seat, a sleeve, or any other downhole tool or component of a downhole tool used for zonal isolation.

6. The method according to claim 1 , wherein the material is an anode of a galvanic system, and wherein the at least the portion of the isolation device further comprises a cathode of the galvanic system.

7. The method according to claim 6 , wherein the anode and the cathode are a non-metal, metal, or metal alloy, and wherein the metal or metal of the metal alloy is selected from the group consisting of magnesium, aluminum, zinc, cerium, beryllium, tin, iron, nickel, copper, titanium, oxides of any of the foregoing, and combinations thereof.

8. The method according to claim 1 , wherein the altered surface is an anodizing layer.

9. The method according to claim 1 , wherein the sealant is a degradable substance.

10. The method according to claim 9 , wherein the sealant initially protects the altered surface from an acid treatment.

11. The method according to claim 1 , wherein the surface treatment is a chemical or physical method.

12. The method according to claim 1 , wherein the altered surface has a specific thickness.

13. The method according to claim 12 , wherein the surface is altered to provide two or more altered surface layers.

14. The method according to claim 13 , wherein the thickness of the altered surface or the two or more altered surface layers is selected such that the portion of the material dissolves in the desired amount of time.

15. The method according to claim 1 , further comprising the step of placing the isolation device into a portion of the wellbore, wherein the step of placing is performed prior to the step of contacting or allowing the isolation device to come in contact with the electrolyte.

16. The method according to claim 1 , further comprising the step of removing all or a portion of the dissolved anode, wherein the step of removing is performed after the step of causing or allowing at least the portion of the layers of the anode to dissolve.

17. A wellbore isolation device comprising:
a material that dissolves via corrosion when in contact with a wellbore fluid, an altered surface, wherein the altered surface comprises the material after being subjected to a surface treatment that modifies the composition of a treated portion of the wellbore isolation device, wherein the altered surface delays corrosion of the material for a desired amount of time, wherein the altered surface is a layer that contains pores, wherein the wellbore isolation device further comprises a sealant placed over the altered surface, wherein the sealant fills the pores; and
wherein the material is a metal alloy that is operable to undergo galvanic corrosion in the presence of an electrolyte without a distinct cathode being present, the metal alloy comprising magnesium in a concentration of at least 85% by volume of the metal alloy.

Assignees

• Halliburton Energy Services Inc

Inventors

• Fripp Michael L
• Walton Zachary W
• Murphree Zachary R

Classifications

• E21B43/16

  Enhanced recovery methods for obtaining hydrocarbons · CPC title

• E21B43/14

  Obtaining from a multiple-zone well · CPC title

• C09K8/02

  Well-drilling compositions · CPC title

• E21B33/1208 Primary

  characterised by the construction of the sealing or packing means (E21B33/1277 takes precedence) · CPC title

• E21B43/28

  Dissolving minerals other than hydrocarbons, e.g. by an alkaline or acid leaching agent (E21B43/241 takes precedence) · CPC title