Process to produce oil or gas from a subterranean formation using a chelating agent

Patent metadata

Field	Value
Publication number	US-10995257-B2
Application number	US-201314406706-A
Country	US
Kind code	B2
Filing date	Jun 14, 2013
Priority date	Jun 18, 2012
Publication date	May 4, 2021
Grant date	May 4, 2021

Abstract

A two-step process to produce oil or gas from a subterranean formation wherein in a first step the subterranean formation is treated with an aqueous composition containing a chelating agent selected from the group of glutamic acid N,N-diacetic acid or a salt thereof (GLDA), aspartic acid N,N-diacetic acid or a salt thereof (ASDA), methylglycine N,N-diacetic acid or a salt thereof (MGDA), and N-hydroxyethyl ethylenediamine N,N′,N′-triacetic acid or a salt thereof (HEDTA) and wherein, in a next step, in the outlet streams from the subterranean formation the aqueous phase is separated from the non-aqueous phase.

First claim

The invention claimed is:

1. A two-step process to produce oil or gas from a subterranean formation, wherein in a first matrix acidizing and/or fracturing step the subterranean formation is treated with an aqueous composition having a pH in the range of 2-6 and containing a chelating agent selected from the group consisting of glutamic acid N,N-diacetic acid or a salt thereof (GLDA), aspartic acid N,N-diacetic acid or a salt thereof (ASDA), methylglycine N,N-diacetic acid or a salt thereof (MGDA), and N-hydroxyethyl ethylenediamine N,N′,N′-triacetic acid or a salt thereof (HEDTA) to promote the production of oil or gas from the subterranean formation as an outlet stream from said subterranean formation, the outlet stream comprising (i) an aqueous phase comprising at least some of said aqueous composition containing said chelating agent, and (ii) a non-aqueous phase comprising said produced oil or gas, and wherein, in a next step the aqueous phase of said outlet stream is separated from the non-aqueous phase.

2. Process of claim 1 , wherein the outlet stream from the subterranean formation comprises an emulsion, said emulsion containing the aqueous phase and the non-aqueous phase and wherein the separation step comprises one or more steps selected from the group consisting of (i) adding a chemical demulsifier, (ii) increasing the temperature of the emulsion, (iii) applying electrostatic fields that promote coalescence, and (iv) reducing the flow velocity, which flow velocity reduction allows gravitational separation of oil or gas and water.

3. Process of claim 1 , wherein the aqueous composition contains 5 to 30 wt % of chelating agent on the basis of the total weight of the composition.

4. Process of claim 1 , wherein the aqueous composition chelating agent comprises GLDA.

5. Process of claim 1 , wherein the composition is a foamed or viscosified composition or is one part of a kit of parts containing in addition a preflush and/or postflush part.

6. Process of claim 1 , wherein the process in addition contains a step of at least partially removing a filter cake that is present in the subterranean formation.

7. Process of claim 1 , wherein the subterranean formation is a carbonate formation, a sandstone formation, a shale formation, a calcium carbonate-containing sandstone formation, a calcium carbonate-containing shale formation, an illitic carbonate formation or an illitic sandstone formation.

8. Process of claim 1 , wherein the composition in addition contains a corrosion inhibitor in an amount of up to 2 volume % on total composition.

9. Process of claim 8 , wherein the corrosion inhibitor is selected from the group consisting of amine compounds, quaternary ammonium compounds, and sulfur compounds.

10. Process of claim 1 , wherein the composition in addition contains a surfactant in an amount of up to 2 volume % on total composition.

11. Process of claim 10 , wherein the surfactant is selected from the group consisting of anionic, amphoteric, nonionic, and cationic surfactants.

12. Process of claim 1 , wherein the composition in addition contains a further additive selected from the group consisting of mutual solvents, anti-sludge agents, surfactants, corrosion inhibitor intensifiers, foaming agents, viscosifiers, wetting agents, diverting agents, oxygen scavengers, carrier fluids, fluid loss additives, friction reducers, stabilizers, rheology modifiers, gelling agents, scale inhibitors, breakers, salts, brines, pH control additives, particulates, crosslinkers, relative permeability modifiers, sulfide scavengers, fibres, and nanoparticles.

13. Process of claim 1 , wherein the composition has a pH of between 3 and 6.

14. Process of claim 1 , wherein the process involves treating the subterranean formation to increase the permeability thereof, remove particles therefrom and/or remove inorganic scale therefrom.

15. Process of claim 1 , wherein the process involves cleaning of a wellbore and/or descaling of an oil/gas production well and production equipment in the production of oil and/or gas from the subterranean formation.

Assignees

• Akzo Nobel Chemicals Int Bv
• Nouryon Chemicals Int Bv

Inventors

• De Wolf Cornelia Adriana
• Nasr-El-Din Hisham
• De Oliveira Barra Estevao
• Bang Edwin Rudolf Antony
• Stanitzek Theodor Johannes

Classifications

• E21B43/35

  specially adapted for separating solids (down-hole drilling fluid separation systems E21B21/002; separating solids from drilling fluids E21B21/065) · CPC title

• C10G1/047

  Hot water or cold water extraction processes · CPC title

• C10G75/02

  by addition of corrosion inhibitors · CPC title

• C09K8/70

  characterised by their form or by the form of their components, e.g. foams · CPC title

• C10G33/02

  with electrical or magnetic means · CPC title