Attenuated acid formulations for acid stimulation

Patent metadata

Field	Value
Publication number	US-12012550-B2
Application number	US-202117548752-A
Country	US
Kind code	B2
Filing date	Dec 13, 2021
Priority date	Dec 13, 2021
Publication date	Jun 18, 2024
Grant date	Jun 18, 2024

Abstract

A method for acid treating a carbonate reservoir with an attenuated acid formulation is provided. The method includes mixing an acidic compound with a hygroscopic chemical to form the attenuated acid formulation, and injecting the attenuated acid formulation into a carbonate formation.

First claim

What is claimed is:

1. A method for treating a carbonate reservoir with an attenuated acid formulation, comprising:
mixing an acidic compound with a hygroscopic chemical to form the attenuated acid formulation, wherein the acidic compound comprises a hydrochloric acid solution and the hydroscopic chemical comprises diethylene glycol, wherein the DEG comprises between 5 and 40 vol. % of the attenuated acid formulation; and
injecting the attenuated acid formulation into a carbonate formation, wherein the pore volume for breakthrough (PV BT ) is less than 0.23 for an attenuated acid formulation comprising either a 28 wt. % or a 36 wt. % solution of HCl.

2. The method of claim 1 , wherein the acidic composition further comprises methane sulfonic acid.

3. The method of claim 1 , wherein the acidic compound comprises a compound that forms an acid in an aqueous solution.

4. The method of claim 1 , wherein the acidic compound comprises an alkylsulfonic acid.

5. The method of claim 4 , wherein the alkylsulfonic acid is methanesulfonic acid (MSA).

6. The method of claim 1 , comprising mixing the acidic compound with the hygroscopic chemical to form the attenuated acid formulation on-the-fly as materials are injected into the formation.

7. The method of claim 1 , wherein the DEG comprises between 20 and 25 vol. % of the attenuated acid formulation.

8. The method of claim 1 , wherein the attenuated acid formulation comprises a surfactant.

9. The method of claim 8 , wherein the surfactant comprises a fluorinated surfactant.

10. The method of claim 1 , wherein the attenuated acid formulation is an emulsion.

11. The method of claim 1 , wherein the attenuated acid formulation is a foam.

12. The method of claim 1 , comprising viscosifying the attenuated acid formulation by a gelling agent.

13. The method of claim 1 , wherein the attenuated acid formulation comprises a viscoelastic surfactant.

14. The method of claim 1 , wherein the attenuated acid formulation comprises a crosslinkable gelling agent.

15. The method of claim 1 , comprising:
acidizing a carbonate matrix with the attenuated acid formulation;
acid fracturing with the attenuated acid formulation;
acidizing an open hole with the attenuated acid formulation;
cleaning a wellbore with the attenuated acid formulation;
cleaning scale with the attenuated acid formulation;
increasing the permeability of injection wells with the attenuated acid formulation;
cleaning up filter cake; or
cleaning up drilling mud.

Assignees

• Saudi Arabian Oil Co

Inventors

• Sayed Mohammed
• Saini Rajesh Kumar

Classifications

• C09K8/703

  Foams · CPC title

• C09K8/685

  containing cross-linking agents · CPC title

• C09K2208/30

  Viscoelastic surfactants [VES] · CPC title

• C09K8/528

  inorganic depositions, e.g. sulfates or carbonates · CPC title

• C09K8/74

  combined with additives added for specific purposes · CPC title