Compositions For Enhanced Fracture Cleanup Using Redox Treatment

Patent metadata

Field	Value
Publication number	US-2016319182-A1
Application number	US-201615205994-A
Country	US
Kind code	A1
Filing date	Jul 8, 2016
Priority date	Apr 17, 2014
Publication date	Nov 3, 2016
Grant date	—

Abstract

A cleanup fluid for reducing a viscosity of a residual viscous material in fractures of a hydrocarbon-bearing formation is disclosed. The cleanup fluid includes an acid precursor, the acid precursor operable to trigger an exothermic reaction component and the exothermic reaction component operable to generate heat, where the heat is operable to reduce a viscosity of the residual viscous material to create a reduced viscosity material, the reduced viscosity material operable to flow from the fractures.

First claim

What is claimed is:

1 . A cleanup fluid for reducing a viscosity of a viscous material in and around a wellbore of a hydrocarbon-bearing formation, the cleanup fluid comprising:
an acid precursor, the acid precursor operable to trigger an exothermic reaction component; and the exothermic reaction component operable to generate heat,
where the heat is operable to reduce a viscosity of the viscous material to create a reduced viscosity material, the reduced viscosity material operable to flow to allow increased fluid flow in the wellbore.

2 . The cleanup fluid of claim 1 , where the exothermic reaction component comprises an ammonium containing compound and a nitrite containing compound.

3 . The cleanup fluid of claim 2 , where the ammonium containing compound comprises NH 4 Cl and the nitrite containing compound comprises NaNO 2 .

4 . The cleanup fluid of claim 3 , where the concentration of the NH 4 Cl and NaNO 2 is about 3 M.

5 . The cleanup fluid of claim 1 , where the acid precursor is selected from the group consisting of triacetin, methyl acetate, hydrochloric acid, acetic acid, and combinations thereof.

6 . The cleanup fluid of claim 1 , where the acid precursor comprises triacetin.

7 . The cleanup fluid of claim 1 , where the exothermic reaction component reacts when a temperature within the hydrocarbon-bearing formation reaches about 120° F.

8 . The cleanup fluid of claim 1 , further comprising a cross-linked gel.

9 . The cleanup fluid of claim 1 , further comprising a viscous fluid component and a proppant component.

10 . The cleanup fluid of claim 9 , where the viscous fluid component comprises a compound selected from the group consisting of: carboxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl hydroxyethyl cellulose, hydroxypropyl cellulose, methyl hydroxyl ethyl cellulose, hydroxypropyl guar, carboxymethyl guar, guar cross-linked boron ions from an aqueous borax/boric acid solution, guar cross-linked with organometallic compounds, aluminum phosphate-ester oil gels, and mixtures thereof.

11 . The cleanup fluid of claim 1 , further comprising an aqueous guar solution having a concentration of guar gum between about 0.1% and about 15% by volume.

12 . The cleanup fluid of claim 1 , further comprising an aqueous guar solution having a concentration of guar gum between about 0.1% and about 10% by volume.

13 . The cleanup fluid of claim 1 , further comprising an aqueous guar solution having a concentration of guar gum between about 1% and about 10% by volume.

14 . The cleanup fluid of claim 1 , further comprising an aqueous guar solution having a concentration of guar gum between about 2% and about 8% by volume.

15 . The cleanup fluid of claim 1 , further comprising an aqueous guar solution having a concentration of guar gum between about 4% and about 6% by volume.

16 . The cleanup fluid of claim 1 , further comprising an ammonium containing compound selected from the group consisting of: ammonium chloride, ammonium bromide, ammonium nitrate, ammonium sulfate, ammonium carbonate, ammonium hydroxide, and mixtures thereof.

17 . The cleanup fluid of claim 1 , further comprising a nitrite containing compound selected from the group consisting of: sodium nitrite, potassium nitrite, and mixtures thereof.

18 . A method for use of the cleanup fluid of claim 1 , the method comprising the steps of:
injecting the acid precursor and the exothermic reaction component into the wellbore; allowing the exothermic reaction component to react in situ to produce heat and nitrogen gas, the heat and nitrogen gas operable to increase the temperature and pressure in situ; and reducing the viscosity of the viscous material to create the reduced viscosity material.

19 . The method of claim 18 , where the exothermic reaction component comprises an ammonium containing compound and a nitrite containing compound.

20 . The method of claim 19 , where the ammonium containing compound comprises NH 4 Cl and the nitrite containing compound comprises NaNO 2 .

21 . The method of claim 18 , where the acid precursor is selected from the group consisting of triacetin, methyl acetate, hydrochloric acid, acetic acid, and combinations thereof.

22 . The method of claim 18 , where the exothermic reaction component comprises an ammonium containing compound selected from the group consisting of: ammonium chloride, ammonium bromide, ammonium nitrate, ammonium sulfate, ammonium carbonate, ammonium hydroxide, and mixtures thereof.

23 . The method of claim 18 , where the exothermic reaction component comprises a nitrite containing compound selected from the group consisting of: sodium nitrite, potassium nitrite, and mixtures thereof.

24 . The method of claim 18 , where the viscous material comprises asphaltenes and corrosion products in the wellbore.

25 . The method of claim 24 , where the corrosion products are selected from the group consisting of: iron oxides, iron sulfides, sodium chloride, calcium carbonate, silica, and mixtures thereof.

26 . The method of claim 18 , wherein the step of reducing the viscosity of the viscous material to create the reduced viscosity material increases the injectivity of the wellbore.

27 . The method of claim 18 , wherein the step of reducing the viscosity of the viscous material to create the reduced viscosity material increases the productivity of the hydrocarbon-bearing reservoir.

28 . The method of claim 18 , further comprising the step of increasing nitrogen lift in the wellbore.

Assignees

• Saudi Arabian Oil Co

Inventors

• Al-Nakhli Ayman R
• Abass Hazim H
• Al-Otaibi Ahmad S

Classifications

• E21B43/26

  by forming crevices or fractures · CPC title

• E21B37/00

  Methods or apparatus for cleaning boreholes or wells (E21B21/00 takes precedence) · CPC title

• C09K8/528

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

• C09K8/524 Primary

  organic depositions, e.g. paraffins or asphaltenes · CPC title

• E21B43/267

  reinforcing fractures by propping · CPC title