Method for the assisted recovery of petroleum

Patent metadata

Field	Value
Publication number	US-9938449-B2
Application number	US-201113992336-A
Country	US
Kind code	B2
Filing date	Dec 8, 2011
Priority date	Dec 9, 2010
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

Abstract

A method for the assisted recovery of petroleum in a deposit by means of the introduction of an aqueous solution of a hydrosoluble polymer into the deposit is characterized in that the aqueous solution is prepared by dissolving a polymer-based composition containing at least one hydrosoluble polymer, at least one radical capturing agent, and at least one sacrificial agent, in an aqueous solution subjected to a step of treatment with at least one deoxygenating agent, prior to the introduction of the polymer-based composition.

First claim

The invention claimed is:

1. A process for enhanced oil recovery in a deposit, comprising the preparation of an aqueous solution of at least one water-soluble polymer and the introduction of the said prepared solution into the deposit characterized in that said aqueous solution of at least one water-soluble polymer has a viscosity included in the range of from 2 to 200 cps, the viscosity measurements being carried out at 20° C. with a Brookfield viscometer with a UL or S85 module and is prepared with the successive following steps:
treating an aqueous solution by adding at least one oxygen scavenger, in a stoichiometric excess relative to the oxygen dissolved in the aqueous solution, of at least one times the stoichiometry (100%) up to 50 times the stoichiometry;
providing a polymer-based composition containing at the same time at least one water-soluble polymer, at least one free-radical scavenger, and at least one sacrificial agent, said water-soluble polymer being chosen from water-soluble organic polymers having a molecular weight greater than or equal to 1 million g/mol, being based on acrylamide copolymerized with acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid or N-vinylpyrrolidone, and being in the form of a powder or an inversion emulsion;
then, after the deoxygenation step, dissolving, with the treated aqueous solution, the polymer-based composition containing at the same time the at least one water-soluble polymer, the at least one free-radical scavenger, and the at least one sacrificial agent.

2. The process for enhanced oil recovery as claimed in claim 1 , characterized in that, before the treatment with at least one oxygen scavenger, the aqueous solution contains at least 50 ppb of oxygen.

3. The process for enhanced oil recovery as claimed in claim 1 , characterized in that an alkaline agent and/or a composition containing at least one surfactant is introduced into the aqueous solution, before or after the step of treating with an oxygen scavenger, and before, after or in parallel with the step of dissolving the polymer-based composition.

4. The process for enhanced oil recovery as claimed in claim 1 , characterized in that the aqueous solution is subjected to an additional step of treating with at least one oxygen scavenger, before or after the introduction of the polymer-based composition.

5. The process for enhanced oil recovery as claimed in claim 4 , characterized in that the aqueous solution is subjected to an additional step of treating with at least one oxygen scavenger, just before the introduction of the aqueous composition containing the water-soluble polymer(s) into the deposit.

6. The process for enhanced oil recovery as claimed in claim 1 , characterized in that the polymer-based composition does not contain oxygen scavenger.

7. The process for enhanced oil recovery as claimed in claim 1 , characterized in that the polymer-based composition is constituted of at least 30% by weight of an active part which comprises exclusively the water-soluble polymer(s), the free-radical scavenger(s) and the sacrificial agent(s) and the polymer-based composition comprises from 0 to 70% by weight of an additive part which comprises all the other components present in the composition, and in that the active part of the composition contains at least 35% by weight of water-soluble polymer.

8. The process for enhanced oil recovery as claimed in claim 7 , wherein the active part of the composition contains at least 50% by weight of water-soluble polymer.

9. The process for enhanced oil recovery as claimed in claim 1 , characterized in that the free-radical scavenger is chosen from N,N′-diethylthiourea, N,N′-dimethylthiourea, mercaptobenzothiazole and mercaptobenzoimidazole.

10. The process for enhanced oil recovery as claimed in claim 1 , characterized in that the polymer-based composition is constituted of at least 30% by weight of an active part which comprises exclusively the water-soluble polymer, the free-radical scavenger and the sacrificial agent and the polymer-based composition comprises from 0 to 70% by weight of an additive part which comprises all the other components present in the composition, and in that the amount of free-radical scavenger(s) represents from 0.1% to 35% by weight relative to the weight of the active part of the polymer-based composition.

11. The process for enhanced oil recovery as claimed in claim 1 , characterized in that the sacrificial agent is chosen from glycerol, propylene glycol, trimethylene glycol, isopropanol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2,4-butanetriol, pentaerythritol (PET), trimethylolethane, neopentyl glycol, 1,2-pentanediol, 2,4-pentanediol, 2,3-pentanediol, trimethylolpropane, 1,5-pentanediol and partially or totally hydrolyzed polyvinyl alcohol.

12. The process for enhanced oil recovery as claimed in claim 1 , characterized in that the polymer-based composition is constituted of at least 30% by weight of an active part which comprises exclusively the water-soluble polymer, the free-radical scavenger and the sacrificial agent and the polymer-based composition comprises from 0 to 70% by weight of an additive part which comprises all the other components present in the composition, and in that the amount of sacrificial agent(s) ranges from 0.1% to 35% by weight relative to the weight of the active part of the polymer-based composition.

13. The process for enhanced oil recovery as claimed in claim 1 , characterized in that the oxygen scavenger is chosen from sulfites, bisulfites, bisulfites as a mixture with sodium borohydride, metabisulfites, dithionites of alkali metals or alkaline-earth metals, and hydrazine and its hydroxylamine derivatives.

14. The process for enhanced oil recovery as claimed in claim 1 , wherein the stoichiometric excess ranges from 1 time to 20 times the stoichiometry.

15. The process for enhanced oil recovery as claimed in claim 1 , wherein the molecular weight is in a range of from 1 to 25 million g/mol.

Assignees

• Favero Cedrick
• Spcm Sa

Inventors

• Favero Cedrick

Classifications

• C09K8/588 Primary

  characterised by the use of specific polymers {(polymeric surfactants C09K8/584)} · CPC title

• E21B43/16

  Enhanced recovery methods for obtaining hydrocarbons · CPC title