Acid stimulation of carbonate formation with carbon dioxide-responsive diverting agent

Patent metadata

Field	Value
Publication number	US-12497881-B2
Application number	US-202418629388-A
Country	US
Kind code	B2
Filing date	Apr 8, 2024
Priority date	Apr 8, 2024
Publication date	Dec 16, 2025
Grant date	Dec 16, 2025

Abstract

A method of acid stimulation that includes: injecting a first acid into a subterranean carbonate formation, the first acid dissolving a first portion of a carbonate material in the subterranean carbonate formation to form a first group of channels in a first zone within the subterranean carbonate formation while generating carbon dioxide (CO 2 ); injecting a diverting agent into the first group of channels, the injected diverting agent reacting with the CO 2 and forming a gel to seal the first group of channels; and injecting a second acid into the subterranean carbonate formation, the second acid dissolving a second portion of the carbonate material in the subterranean carbonate formation to form a second group of channels in a second zone within the subterranean carbonate formation, the second zone having a permeability lower than the first zone, the gel blocking the second acid from entering the first group of channels.

First claim

What is claimed is:

1 . A method of acid stimulation, the method comprising:
injecting a first acid into a subterranean carbonate formation through a wellbore, the first acid dissolving a first portion of a carbonate material in the subterranean carbonate formation to form a first group of flow channels in a first zone within the subterranean carbonate formation while generating carbon dioxide (CO 2 ); injecting a diverting agent into the first group of flow channels through the wellbore, wherein the diverting agent comprises an anionic surfactant and an amine, the anionic surfactant comprising a dodecyl or longer hydrocarbon group, the injected diverting agent reacting with the CO 2 and forming a gel to seal the first group of flow channels; and injecting a second acid into the subterranean carbonate formation through the wellbore, the second acid dissolving a second portion of the carbonate material in the subterranean carbonate formation to form a second group of flow channels in a second zone within the subterranean carbonate formation, the second zone having a permeability lower than that of the first zone, the gel blocking the second acid from entering the first group of flow channels.

2 . The method of claim 1 , further comprising, after injecting the second acid, removing the gel from the first group of flow channels.

3 . The method of claim 2 , wherein the removing comprises thermally decomposing the gel.

4 . The method of claim 2 , wherein the removing comprises injecting a purge gas into the subterranean carbonate formation through the wellbore, the purge gas removing the CO 2 from the gel and converting the gel into a fluid.

5 . The method of claim 1 , wherein CO 2 is formed in the second group of flow channels from the injection of the second acid, further comprising injecting the diverting agent into the second group of flow channels, the injected diverting agent reacting with the CO 2 within the second group of flow channels and forming a gel to seal the second group of flow channels.

6 . The method of claim 1 , wherein the first acid comprises hydrochloric acid (HCl), sulfuric acid (H 2 SO 4 ), phosphoric acid (H 3 PO 4 ), or sulfamic acid.

7 . The method of claim 1 , wherein the first acid comprises formic acid, hydroxyacetic acid, acetic acid, citric acid, or methane sulphonic acid.

8 . The method of claim 1 , wherein the anionic surfactant comprises sodium dodecyl sulfate (SDS), sodium tetradecyl sulfate (STS), sodium hexadecyl sulfate (SHS), or sodium octadecyl sulfate (SOS).

9 . The method of claim 1 , wherein the amine comprises diethylenetriamine (DETA), bis(hexamethylene)triamine (BHMTA), or 2-(dimethylamino) ethanol (DMAE).

10 . A method of acid stimulation, the method comprising:
forming a first flow channel in a subterranean carbonate formation by dissolving a carbonate material using an acid while generating carbon dioxide (CO 2 ) within the first flow channel; injecting a diverting agent into the first flow channel, the diverting agent comprising an anionic surfactant with a dodecyl or longer hydrocarbon chain group and an amine, the injected diverting agent reacting with the CO 2 to form a non-flowable gel within the first flow channel that seals the first flow channel; forming a second flow channel in the subterranean carbonate formation by dissolving a second portion of the carbonate material using the acid while generating CO 2 within the second flow channel; and removing the non-flowable gel from the first flow channel.

11 . The method of claim 10 , wherein the removing comprises thermally decomposing the gel.

12 . The method of claim 10 , wherein the removing comprises injecting a purge gas into the subterranean carbonate formation through the wellbore, the purge gas removing the CO 2 from the gel and converting the gel into a fluid.

13 . The method of claim 10 , wherein the acid comprises hydrochloric acid (HCl), sulfuric acid (H 2 SO 4 ), phosphoric acid (H 3 PO 4 ), sulfamic acid, formic acid, hydroxyacetic acid, acetic acid, citric acid, or methane sulphonic acid.

14 . The method of claim 10 , wherein the acid is a solution with an acid concentration of between 5 wt % and 28 wt %.

15 . The method of claim 10 , wherein the anionic surfactant comprises sodium dodecyl sulfate (SDS), sodium tetradecyl sulfate (STS), sodium hexadecyl sulfate (SHS), or sodium octadecyl sulfate (SOS), and wherein the amine comprises diethylenetriamine (DETA), bis(hexamethylene)triamine (BHMTA), or 2-(dimethylamino) ethanol (DMAE).

16 . The method of claim 10 , wherein the diverting agent is an aqueous solution comprising the anionic surfactant at a concentration of at least 0.25 mol/L and the amine at a concentration of at least 0.25 mol/L.

17 . A method of acid stimulation, the method comprising:
injecting an acid solution of hydrochloric acid (HCl) into a subterranean carbonate formation through a wellbore, the HCl dissolving a carbonate material in the subterranean carbonate formation to form a first group of flow channels in a first zone within the subterranean carbonate formation while generating carbon dioxide (CO 2 ), the first group of flow channels; and injecting a diverting agent into the subterranean carbonate formation through the wellbore, the diverting agent comprising an anionic surfactant with a dodecyl or longer hydrocarbon chain group and an amine, the injected diverting agent reacting with the CO 2 and forming a non-flowable gel to seal the first group of flow channels.

18 . The method of claim 17 , further comprising alternately repeating the steps of injecting the acid solution and injecting the diverting agent, wherein each step of injecting the acid solution forms a new flow channel.

19 . The method of claim 18 , further comprising extracting hydrocarbons from a reservoir using the flow channels formed within the subterranean carbonate formation.

Assignees

• Saudi Arabian Oil Co

Inventors

• Chen Shaohua
• Xu Limin
• Alharbi Bader G
• Alsultan Sharefah A
• Huang Tianping

Classifications

• C09K8/74

  combined with additives added for specific purposes · CPC title

• C09K8/602

  containing surfactants · CPC title

• E21B43/2605 Primary

  using gas or liquefied gas · CPC title

• C09K8/506

  containing organic compounds · CPC title

• E21B43/27 Primary

  by use of eroding chemicals, e.g. acids · CPC title