Packer fluid with nanosilica dispersion and sodium bicarbonate for thermal insulation

Patent metadata

Field	Value
Publication number	US-11753574-B2
Application number	US-202117390075-A
Country	US
Kind code	B2
Filing date	Jul 30, 2021
Priority date	Jul 30, 2021
Publication date	Sep 12, 2023
Grant date	Sep 12, 2023

Abstract

A downhole system includes a packer sealing an annular space around a downhole tubing and an insulating packer fluid positioned within the annular space and adjacent to the packer. The insulating packer fluid includes a sodium bicarbonate activator and an acidic nanosilica dispersion having silica nanoparticles and a stabilizer, wherein the pH of the acidic nanosilica dispersion ranges from 2 to 5, and the silica nanoparticles form at least 20 percent by weight of the acidic nanosilica dispersion.

First claim

What is claimed is:

1. A downhole system, comprising:
a packer sealing an annular space between a downhole inner tubing and an outer tubing; and
an insulating packer fluid if (i) positioned within the annular space and adjacent the packer, and (ii) insulating the inner tubing, wherein the insulating packer fluid comprises:
an acidic nanosilica dispersion, comprising:
silica nanoparticles; and
a stabilizer;
wherein the pH of the acidic nanosilica dispersion ranges from 2 to 5; and

a sodium bicarbonate activator.

2. The system of claim 1 , wherein the acidic nanosilica dispersion has a pH ranging from 3.5 to 4.

3. The system of claim 1 , wherein a ratio of the sodium bicarbonate activator to the acidic nanosilica dispersion ranges from 1:3 to 1:5.

4. The system of claim 1 , wherein the acidic nanosilica dispersion is stabilized by the stabilizer, and wherein the stabilizer is oxy chloride.

5. The system of claim 1 , wherein the silica nanoparticles are surface modified to have a cationic surface.

6. The system of claim 5 , wherein the silica nanoparticles are surface modified using positive ions.

7. The system of claim 1 , wherein the silica nanoparticles comprise at least one ion bonded to a surface of the silica nanoparticles, wherein the at least one ion is selected from ions of aluminum, aluminum sulfate, ferric chloride, and ferric sulfate.

8. The system of claim 1 , wherein the silica nanoparticles form between 5 to 50 percent by weight of the acidic nanosilica dispersion.

9. A method of insulating an annular space around a downhole tubing comprising:
pumping an acidic nanosilica dispersion and a sodium bicarbonate activator downhole to the annular space, wherein the acidic nanosilica dispersion comprises: silica nanoparticles modified with a cationic species; and a stabilizer,
mixing the acidic nanosilica dispersion and the sodium bicarbonate activator to provide an insulating packer fluid;
waiting a period of time for the insulating packer fluid to statically age and gel into an insulating packer gel; and
leaving the insulating packer gel in the annular space to insulate the downhole tubing as a fluid is flowed through the downhole tubing.

10. The method of claim 9 , wherein the acidic nanosilica dispersion and the sodium bicarbonate activator are introduced separately into the annular space.

11. The method of claim 10 , wherein the sodium bicarbonate activator is pumped into the annular space after the acidic nanosilica dispersion has been pumped into the annular space.

12. The method of claim 9 , wherein a ratio of the sodium bicarbonate activator to the acidic nanosilica dispersion that is pumped into the annular space ranges from 1:3 to 1:5.

13. The method of claim 9 , wherein the acidic nanosilica dispersion is mixed with the sodium bicarbonate activator under downhole conditions.

14. The method of claim 9 , wherein the annular space is sealed at one or both axial ends with at least one packer assembly.

15. The method of claim 14 , wherein the acidic nanosilica dispersion and the sodium bicarbonate activator are pumped through a valved flowline into the annular space.

16. A downhole system, comprising:
a packer sealing an annular space between a downhole inner tubing and an outer tubing; and
an insulating packer gel (i) positioned within the annular space and adjacent the packer, and (ii) insulating the inner tubing, wherein the insulating packer gel comprises:
a plurality of interconnected silica nanoparticles;
a stabilizer; and
sodium bicarbonate.

17. The system of claim 16 , wherein the outer tubing is casing.

18. The system of claim 16 , wherein the pH of the insulating packer gel is less than 7.

19. The system of claim 16 , wherein the silica nanoparticles are modified with a cationic species.

Assignees

• Saudi Arabian Oil Co

Inventors

• Wagle Vikrant
• Kalgaonkar Rajendra
• Al-Yami Abdullah S

Classifications

• C09K8/5045 Primary

  containing inorganic compounds · CPC title

• C09K8/516

  characterised by their form or by the form of their components, e.g. encapsulated material · CPC title

• C09K2208/10

  Nanoparticle-containing well treatment fluids · CPC title

• C09K8/508

  macromolecular compounds {(C09K8/512 takes precedence)} · CPC title

• E21B33/138

  Plastering the borehole wall; Injecting into the formation · CPC title