Treatment of subterranean formations

Patent metadata

Field	Value
Publication number	US-11753583-B2
Application number	US-202017429807-A
Country	US
Kind code	B2
Filing date	Feb 11, 2020
Priority date	Feb 12, 2019
Publication date	Sep 12, 2023
Grant date	Sep 12, 2023

Abstract

A method of treating a subterranean formation by contacting the formation with the following: (a) an ammonium compound; (b) an oxidizing agent selected from a perchlorate or a nitrite or combinations thereof; and (c) one or more acids, at least one of which is a bisulfate salt.

First claim

The invention claimed is:

1. A method of treating a subterranean formation, the method comprising contacting the formation with:
(a) an ammonium compound;
(b) an oxidizing agent selected from a perchlorate or a nitrite or combinations thereof; and
(c) one or more acids, at least one of which is a bisulfate salt,
wherein said bisulfate salt is treated in the method to produce gas which supplements gas produced by reaction of said ammonium compound and said oxidizing agent, and
wherein, in the method, said ammonium compound and said oxidizing agent are contacted underground during passage towards or after arrival at a region of said subterranean formation it is desired to treat, wherein the gas produced includes nitrogen atoms originating in the bisulfate salt.

2. The method according to claim 1 , wherein the method comprises treating the formation to create or enhance a fracture in the formation.

3. The method according to claim 1 , wherein said oxidizing agent comprises a nitrite which, optionally, is sodium nitrite.

4. The method according to claim 1 , wherein said ammonium compound and said oxidizing agent are contacted so they react and nitrogen and carbon dioxide are generated in the formation.

5. The method according to claim 1 , wherein said oxidizing agent is a nitrite and wherein a ratio (A) defined as the number of moles of ammonium compound divided by the number of moles of nitrite contacted with the formation and/or reacted in the formation is in the range 0.05 to 2.0.

6. The method according to claim 1 , wherein said ammonium compound is selected from ammonium fluoride, ammonium chloride, ammonium bromide, ammonium iodide, ammonium nitrate, ammonium sulfate, ammonium hydrogensulfate, ammonium carbonate, ammonium carbamate, ammonium bicarbonate, ammonium hydroxide, ammonium acetate, ammonium borates, ammonium chromate, ammonium dichromate, ammonium cyanides, ammonium glutamate, ammonium molybdate, ammonium oxalate, ammonium hydrogenoxalate, ammonium phosphate monobasic, ammonium phosphate dibasic, ammonium thiosulfate, ammonium formate, ammonium sulfamate, ammonium sulfite, ammonium persulfate, ammonium sulfide, ammonium tartrate dibasic, ammonium thiocyanate, ammonium dihydrogen phosphate and ammonium glycinate.

7. The method according to claim 1 , wherein said ammonium compound includes, in addition to NH 4 + moiety, a second moiety which generates a gas on reaction with said oxidizing agent and/or said bisulfate salt.

8. The method according to claim 7 , wherein said second moiety comprises a sulfamate, carbonate or bicarbonate moiety.

9. The method according to claim 1 , wherein a ratio (B) defined as the number of moles of ammonium compound divided by the total number of moles of acid contacted with the formation and/or reacted with the ammonium compound and oxidizing agent in the formation is greater than 0 and is 10 or less; and/or wherein a ratio (C) defined as the number of moles of ammonium compound divided by the sum of the number of moles of one or more acids which are arranged to react with other materials contacted with the formation to produce a gas is greater than 0 and is 10 or less; and/or wherein a ratio (H) defined as the number of moles of oxidizing agent divided by the total number of moles of acid contacted with the formation is in the range 0.1-10.

10. The method according to claim 1 , wherein said ammonium compound is provided in water and the method comprises selecting an aqueous solution, slurry or emulsion of said ammonium compound; and wherein said oxidizing agent is provided in water and the method comprises selecting an aqueous solution, slurry or emulsion of said oxidizing agent.

11. The method according to claim 1 , wherein:
the sum of the total weight in grams (g) of ammonium compound, oxidizing agent and acid(s) introduced into the formation is herein referred to as SUM-W;
the sum of the total volume in cm 3 of gas generated by reaction of ammonium compound, oxidizing agent and said acid(s) is herein referred to as SUM-V;
wherein, in the method, the Reaction Efficiency is defined as SUM-V divided by SUM-W;
wherein the Reaction Efficiency is at least 100 cm 3 /g and is less than 300 cm 3 /g.

12. The method according to claim 1 , wherein the method uses formulations comprising said ammonium compound, said oxidizing agent and/or said one or more acids and wherein said formulations include one or more co-solvents selected from methanol or formamide.

13. The method according to claim 1 , wherein the method comprises producing pulses of pressure within the formation by controlling contact and/or amounts of said ammonium compound, said oxidizing agent and/or said acid within the formation.

14. The method according to claim 1 , wherein said method includes introducing proppant and/or microproppant in one or more of formulations used in said method, so as to prop any fractures or microfractures formed as a result of the method.

15. A method of treating a subterranean formation, the method comprising contacting the formation with:
(a) an ammonium compound;
(b) an oxidizing agent selected from a perchlorate or a nitrite or combinations thereof; and
(c) one or more acids, at least one of which is a bisulfate salt,
wherein said bisulfate salt is treated in the method to produce gas which supplements gas produced by reaction of said ammonium compound and said oxidizing agent, and
wherein, in the method, said ammonium compound and said oxidizing agent are contacted underground during passage towards or after arrival at a region of said subterranean formation it is desired to treat, wherein said bisulfate salt is ammonium bisulfate.

16. A method of treating a subterranean formation, the method comprising contacting the formation with:
(a) an ammonium compound;
(b) an oxidizing agent selected from a perchlorate or a nitrite or combinations thereof; and
(c) one or more acids, at least one of which is a bisulfate salt,
wherein said bisulfate salt is treated in the method to produce gas which supplements gas produced by reaction of said ammonium compound and said oxidizing agent, and
wherein, in the method, said ammonium compound and said oxidizing agent are contacted underground during passage towards or after arrival at a region of said subterranean formation it is desired to treat, wherein said bisulfate salt is used in combination with an acid (2) which is sulfamic acid.

17. A method of treating a subterranean formation, the method comprising contacting the formation with:
(a) an ammonium compound;
(b) an oxidizing agent selected from a perchlorate or a nitrite or combinations thereof; and
(c) one or more acids, at least one of which is a bisulfate salt,
wherein said bisulfate salt is treated in the method to produce gas which supplements gas produced by reaction of said ammonium compound and said oxidizing agent, and
wherein, in the method, said ammonium compound and said oxidizing agent are contacted underground during passage towards or after arrival at a region of said subterranean formation it is desired to treat,
wherein the method comprises treating the formation to create or enhance a fracture in the formation by production of gas within the formation, wherein in the method the sum of the wt % of a formulation (F1) comprising said ammonium compound, a formulation (F2) comprising said oxidizing agent and a formulation (F3) comprising said bisulfate salt introduced into the formation is at least 98 wt % of the total weight of materials introduced into the formation as part of the fracturing of the formation, wherein

Assignees

• Innospec Ltd

Inventors

• Mcrobbie Ian Malcolm
• Trenholme William

Classifications

• C09K8/72 Primary

  Eroding chemicals, e.g. acids · CPC title

• C09K8/665 Primary

  containing inorganic compounds (proppants C09K8/80) · CPC title

• C09K8/845

  containing inorganic compounds · CPC title

• C09K8/94

  Foams · CPC title

• C09K8/703

  Foams · CPC title