METHOD OF REMOVING OIL-BASED BARITE FILTER CAKE

• US 20200131432A1
• Filed: 12/30/2019
• Published: 04/30/2020
• Est. Priority Date: 07/14/2017
• Status: Active Grant

• Current Assignee: King Fahd University of Petroleum & Minerals (Government of Saudi Arabia)
• Original Assignee: King Fahd University of Petroleum & Minerals (Government of Saudi Arabia)
• Inventors: MAHMOUD, Mohamed, ELKATATNY, Salah El-Din
• Granted Patent: US 11,124,695 B2
• Time in Patent Office: Days
• CPC Class Codes: C09K 2208/24 Bacteria or enzyme containing gel breakers
• CPC Class Codes: C09K 2208/26 Gel breakers other than bacteria or enzymes
• CPC Class Codes: C09K 8/03 Specific additives for general use in well-drilling compositions
• CPC Class Codes: C09K 8/52 Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning
• CPC Class Codes: C09K 8/524 organic depositions, e.g. paraffins or asphaltenes
• CPC Class Codes: C09K 8/62 Compositions for forming crevices or fractures
• CPC Class Codes: C09K 8/74 combined with additives added for specific purposes
• CPC Class Codes: E21B 37/00 Methods or apparatus for cleaning boreholes or wells E21B21/00 takes precedence

Abstract

The present invention relates to a composition for dissolving an oil-based filter cake in a wellbore, and a single-step method of use. The composition comprises a chelating agent, a converting agent, a polymer removal agent, a mutual solvent, and a surfactant. The present invention also relates to a multi-step method of dissolving an oil-based filter cake using similar components. Both single-step and multistep methods may be used to dissolve oil-based filter cakes comprising barite as a weighting material.

Claims

1-11. -11. (canceled)

12. A single-step method of dissolving an oil-based filter cake in a wellbore, comprising:

contacting the oil-based filter cake in the wellbore with a composition for 18-30 h, wherein at least 80 wt % of the oil-based filter cake dissolves with respect to a total weight of the filter cake prior to the contacting,

wherein the oil-based filter cake comprises 30-90 wt % barium sulfate with respect to a total weight of the filter cake prior to the contacting,

wherein the composition comprises;

17-30 wt % of a chelating agent;

2-10 wt % of a converting agent;

3-12 wt % of a persulfate salt 3-15 wt % of a mutual solvent;

0.05-7.00 wt % of a surfactant; and

a base solvent of water, brine, seawater, or freshwater,

wherein each weight percentage is with respect to a total weight of the composition,

wherein the chelating agent is a salt of at least one selected from the group consisting of diethylenetriaminepentaacetic acid, N-(hydroxyethyl)-ethylenediaminetetraacetic acid, ethylenediaminetetraacetic acid, glutamic acid-N,N diacetic acid, hydroxyethyliminodiacetic acid, methylglycinetetraacetic acid, ethylenediamine-N,N′

-disuccinic acid, ethylene glycol-bis((3-aminoethyl ether)-N,N,N′

,N′

-tetraacetic acid, nitrilotriacetic acid, cyclohexanediaminetetraacetic acid, aminotri(methylene phosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, and citrate,

wherein the converting agent is at least one selected from the group consisting of potassium carbonate, potassium formate, potassium hydroxide, cesium carbonate, and cesium chloride,

wherein the persulfate salt is at least one selected from the group consisting of sodium persulfate, potassium persulfate, ammonium persulfate, and peroxydisulfate, and

wherein the mutual solvent is at least one selected from the group consisting of propylene glycol, ethylene glycol, diethylene glycol, glycerol, and 2-butoxyethanol.

14. The method of claim 12, wherein a ratio of a total volume of the composition to the total weight of the filter cake prior to the contacting is 20-30 mL/g.

15. The method of claim 12, wherein a temperature in the wellbore is 225-380°

F.

17. The method of claim 12, wherein the contacting forms an emulsion.

21. The method of claim 17, wherein the oil-based filter cake further comprises an oil base, and

wherein the emulsion comprises droplets of the oil base dispersed in the composition, the droplets having diameters of 1-100 nm.

22. The method of claim 15, wherein the composition has a corrosion rate of 0.00001-0.01 lb/ft² per 6 h in contact with a steel surface in the wellbore.

23. The method of claim 12, wherein the oil-based filter cake has a thickness in a range of 0.5-3.0 mm.

24. The method of claim 23, wherein the oil-based filter cake is located on a surface of the wellbore,

wherein the surface of the wellbore is a porous rock, and

wherein the surface has a retained permeability of 88-99.3% after the contacting.

25. The method of claim 24, wherein the porous rock is sandstone.

26. The method of claim 12, wherein the barium sulfate is in the form of particles having diameters of 20-55 μ

m.

27. The method of claim 12, wherein during the contacting, the converting agent converts the barium sulfate into a barium product, and

wherein the barium product has a solubility in water that is increased by a factor of at least 5 compared to a solubility of barium sulfate in water at the same temperature.

28. The method of claim 27, wherein the barium product has a lower solubility than BaCl₂.

29. The method of claim 28, wherein the barium product is BaCO₃.

30. The method of claim 12, wherein the mutual solvent is 2-butoxyethanol and glycerol having a 1:

5-5;

1 mass ratio of 2-butoxyethanol to glycerol.

31. The method of claim 12, wherein the surfactant is at least one selected from the group consisting of N-cis-13-docosenoic-N,N-bis(2-hydroxymethyl)-N-methyl ammonium chloride, an alkyl polyglycoside, an ethoxylated alcohol, and a triethyleneglycol monobutyl ether,

wherein the composition further comprises 0.05-2.00 wt % of an emulsifier relative to a total weight of the composition, and

wherein the emulsifier is a linear alkyl benzene sulfonate or a branched alkyl benzene sulfonate.

32. The method of claim 31, wherein the composition consists of the chelating agent, the converting agent, the persulfate salt, the mutual solvent, the surfactant, the emulsifier, and the base solvent.

33. The method of claim 31, wherein the surfactant is N-cis-13-docosenoic-N,N-bis(2-hydroxymethyl)-N-methyl ammonium chloride,

wherein the emulsifier is sodium dodecyl benzene sulphonate, and

wherein the composition has a pH of 10-14.

34. The method of claim 33, wherein the converting agent is potassium carbonate, and

wherein the chelating agent is potassium diethylenetriaminepentaacetate and/or potassium ethylenediaminetetraacetate.

35. The method of claim 33, wherein the composition has a pH of 11-13.

36. The method of claim 34, wherein the mutual solvent is propylene glycol, diethylene glycol, or glycerol.

13. (canceled)

16. (canceled)

18-20. -20. (canceled)