Processes for removing oil from solid wellbore materials and produced water

• US 7,374,690 B2
• Filed: 02/08/2007
• Issued: 05/20/2008
• Est. Priority Date: 08/10/2004
• Status: Active Grant

• Current Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Original Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Inventors: Reddy, B. Raghava
• Primary Examiner(s): Hruskoci; Peter A.
• Application Number:
  US11/672,575
• Publication Number:
  US 20070125714A1
• Time in Patent Office: 467 Days
• Field of Search: 210/708
• US Class Current: 210/708
• CPC Class Codes: C02F 1/26 by extraction
• CPC Class Codes: C02F 1/56 Macromolecular compounds
• CPC Class Codes: C02F 1/681 by addition of solid materials for removing an oily layer on water
• CPC Class Codes: C02F 1/70 by reduction C02F1/4676 takes precedence
• CPC Class Codes: C02F 1/76 with halogens or compounds of halogens C02F1/4674 takes precedence
• CPC Class Codes: C02F 2101/32 Hydrocarbons, e.g. oil
• CPC Class Codes: C02F 2101/325 Emulsions
• CPC Class Codes: C02F 2103/10 from quarries or from mining activities
• CPC Class Codes: C02F 2305/04 Surfactants, used as part of a formulation or alone
• CPC Class Codes: C10G 1/00 Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal mechanical winning of oil from oil-shales, oil-sand, or the like B03B
• CPC Class Codes: E21B 21/068 using chemical treatment

Abstract

Processes for removing oil from a solid wellbore material such as drill cuttings or water such as produced by a subterranean formation include contacting the solid material/water with an amino-substituted polymer such as chitosan and a halogenating agent. The oil separates from the solid material and becomes bound within a flocculated solid. The flocculated solid containing the oil subsequently may be combined with a solvent of the amino-substituted polymer. Further, the flocculated solid may be contacted with a reducing agent, converting the flocculated solid back into the amino-substitute polymer and forming an oil-phase separate from the solvent-phase. The oil-phase may then be separated from the solvent phase and recovered. The solvent in which the amino-substituted polymer is dissolved may be recycled for treating more solid material removed from the well bore.

Claims

1. A process for removing oil from water comprising:

contacting the oil and water with a polymer substituted with an amino group and a halogenating agent, thereby causing at least a portion of the oil to separate from the water and become bound within a flocculated solid formed from the polymer;

separating the flocculated solid from the water;

contacting the flocculated solid with a reducing agent to form an oil phase and an aqueous phase containing the polymer; and

recovering oil from the oil phase.

2. The process of claim 1 wherein the polymer substituted with the amino group comprises chitosan, polyvinylamine, a copolymer of vinylamine and vinylalcohol, polyethylenimine, polylysine, polymyxin, or combinations thereof.

3. The process of claim 1 wherein the halogenating agent comprises sodium hypochlorite, calcium hypochlorite, chlorine, bromine, N-chlorosuccinimide, sodium hypobromite, pyridinium bromide, perbromide, N-bromosuccinimide, chloramine-T, or combinations thereof.

4. The process of claim 1, wherein the reducing agent comprises ascorbic acid, an alkali metal or ammonium salt of a sulfite, bisulfite, dithionite, metabisulfite, or thiosulfate anion, sodium borohydride, potassium borohydride, sodium triacetoxyborohydride, potassium triacetoxyborohydride, or combinations thereof.

5. The process of claim 1, wherein said contacting the flocculated solid with the reducing agent forms the polymer substituted with the amino group from the flocculated solid, and wherein at least a portion of the polymer substituted with the amino group dissolves in the aqueous phase.

6. The process of claim 5, further comprising separating the oil, phase from the aqueous phase and recovering the oil phase.

7. The process of claim 6, further comprising recycling the water in which the polymer substituted with the amino group is dissolved, thereby removing oil from a solid material recovered from a wellbore.

8. The process of claim 7, further comprising contacting the recycled water containing the polymer substituted with the amino group with a solid material recovered from a wellbore and having oil disposed thereon.

9. The process of claim 1, further comprising introducing a de-emulsifying or interfacial tension reducing surfactant to the aqueous phase to improve the separation of the oil phase from the aqueous phase.

10. The process of claim 9, further comprising introducing a salt to the aqueous phase to enhance performance of the surfactant.

11. The process of claim 1, wherein the water is produced from a subterranean formation.

12. The process of claim 11, wherein the water is produced in conjunction with a drilling, cementing, or production operation.

13. The process of claim 12, wherein the drilling, cementing, or production operation is a stimulation operation.

14. The process of claim 13, wherein the stimulation operation is a fracturing or acidizing operation.

15. The process of claim 11, wherein the oil is produced with the water.

16. A process for recovering oil from water, comprising:

flocculating a polymer substituted with an amino group with a halogenating agent to remove at least a portion of the oil from the water and bind the oil in a flocculated solid formed by the polymer, thereby causing at least a portion of the oil to separate from the water;

forming an oil phase and an aqueous phase containing the amino-substituted polymer by deflocculating the amino-substituted polymer by contacting the flocculated solid with a reducing agent; and

recovering oil from the oil-phase.

17. The process of claim 16, wherein the polymer substituted with the amino group comprises chitosan, polyvinylamine, a copolymer of vinylamine and vinylalcohol, polyethylenimine, polylysine, polymyxin, or combinations thereof.

18. The process of claim 16, wherein the halogenating agent comprises sodium hypochlorite, calcium hypochlorite, chlorine, bromine, N-chlorosuccinimide, sodium hypobromite, pyridinium bromide, perbromide, N-bromosuccinimide, chloramine-T, or combinations thereof.

19. The process of claim 16, wherein the reducing agent comprises ascorbic acid, an alkali metal or ammonium salt of a sulfite, bisulfite, dithionite, metabisulfite, or thiosulfate anion, sodium borohydride, potassium borohydride, sodium triacetoxyborohydride, potassium triacetoxyborohydride, or combinations thereof.

20. The method of claim 16 wherein the oil and water are recovered from a subterranean formation during a well servicing operation.