DISINFECTING WATER USED IN A FRACTURING OPERATION

• US 20140299552A1
• Filed: 05/25/2012
• Published: 10/09/2014
• Est. Priority Date: 05/27/2011
• Status: Abandoned Application

• Current Assignee: M-I LLC (SLB)
• Original Assignee: M-I LLC (SLB)
• Inventors: Kapila, Mukesh, Lomond, Perry, Bingham, Richard, Stewart, Colin, Fajt, James R., Gallo, Daniel, McKee, Alan
• Application Number:
  US14/119,967
• Publication Number:
  US 20140299552A1
• Time in Patent Office: Days
• US Class Current: 210/743
• CPC Class Codes: C02F 1/4672 by electrooxydation
• CPC Class Codes: C02F 1/4674 with halogen or compound of halogens, e.g. chlorine, bromine
• CPC Class Codes: C02F 1/722 Oxidation by peroxides
• CPC Class Codes: C02F 1/766 by means of halogens other than chlorine or of halogenated compounds containing halogen other than chlorine
• CPC Class Codes: C02F 1/78 with ozone C02F1/4672 takes precedence
• CPC Class Codes: C02F 2103/10 from quarries or from mining activities
• CPC Class Codes: C02F 2209/04 Oxidation reduction potential [ORP]
• CPC Class Codes: C02F 2209/06 pH
• CPC Class Codes: C02F 2209/29 Chlorine compounds
• CPC Class Codes: C02F 2209/40 Liquid flow rate
• CPC Class Codes: C02F 2303/04 Disinfection
• CPC Class Codes: C02F 5/00 Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents softening using ion-exchange C02F1/42

Abstract

A process for disinfecting a treatment fluid is disclosed, including the step of admixing an aqueous solution comprising two or more oxidants generated via electrolysis of a salt solution with a treatment fluid. The mixed oxidants may be generated on site, using a containerized system.

Claims

1. A process for disinfecting a treatment fluid, comprising:

admixing an aqueous solution comprising two or more oxidants generated via electrolysis of a salt solution with a treatment fluid or treatment fluid precursor.

2. The process of claim 1, further comprising at least one of:

disposing a quantity of one or more salts in a tank;

transporting the tank containing the disposed quantity of one or more salts to a well site to be serviced;

receiving water from a water supply;

treating the water received in a water treatment system to form a conditioned water stream, wherein the treating comprises at least one of filtering, softening, heating, and cooling;

admixing the one or more salts and the water to form the salt solution, wherein the water may be a first portion of the conditioned water stream;

combining the salt solution with additional water to form a diluted salt solution, wherein the additional water may be a second portion of the conditioned water stream;

converting the salt solution to an aqueous solution comprising the two or more oxidants via electrolysis in one or more electrolytic oxidant producing units.

3. The process of claim 1 or claim 2, wherein the one or more salts comprise at least one of an alkali metal halide, an alkaline earth metal halide, and a transition metal halide, and wherein the two or more mixed oxidants comprise two or more of ozone, hydrogen peroxide, hypochlorite, hypochlorous acid, chlorine dioxide, hypobromous acid, bromine, and chlorine.

4. The process of any one of claims 1-3, further comprising measuring at least one of a residual oxidant content, a pH, a free available halogen content, and an oxidation reduction potential, and adjusting at least one of a volumetric ratio of the aqueous solution to the treatment fluid and a contact time based upon the measured at least one of a residual oxidant content, a pH, a free available halogen content, and an oxidation reduction potential.

5. The method of any one of claims 1-4, further comprising at least one of:

storing a quantity of one or more of the salt solution, diluted salt solution, and the aqueous solution in a storage vessel;

cleaning or purging at least one of the tank, the electrolytic oxidant producing unit(s), the sampling system, and the water treatment system using at least one of the water received, a third portion of the conditioned water, the salt solution, and an acid; and

accumulating materials from the cleaning or purging in a process returns tank; and

using at least a portion of the materials from the cleaning or purging to form at least a portion of the treatment fluid;

providing the treated treatment fluid for placement into a wellbore; and

using at least a portion of the treated fluid in a fracturing operation.

6. The method of any one of claims 1-5, further comprising controlling one or more of the electrolysis, the forming a salt solution, the converting the salt solution, the storing, the adjusting, and the measuring using a control system.

7. The method of claim 6, wherein the control system is configured for receiving a signal from and/or sending a signal to a local or a remote source.

8. The method of claim 7, wherein the control system is configured to determine a feed rate of the aqueous solution, adjust a feed rate of the aqueous solution, and/or control the feed rate of the aqueous solution, both in the presence of and absence of receiving or sending the signal with the control system from or to the remote source.

9. The method of claim 6 or claim 7, the process further comprising at least one of:

receiving a signal to adjust a system input or output from the remote source;

transmitting process data to a remote source monitoring the disinfecting process;

receiving a signal indicating at least one of a residual oxidant content, a pH, a free available halogen content, and an oxidation reduction potential of the treated fluid;

receiving a signal indicating a flow rate and/or composition of at least one of the fluid to be disinfected, a treatment fluid precursor, and the treated fluid; and

receiving a signal indicating a property of at least one of the fluid to be disinfected, a treatment fluid precursor, and the treated fluid after contact of the aqueous solution with the fluid to be disinfected;

determining with the control system an aqueous solution flow rate using feedforward and/or feedback control based upon the signals received; and

generating and/or sending a treatment report.

10. The method of any one of claims 1-9, wherein the aqueous solution comprises hypobromous acid formed by at least one of:

electrolysis of a salt solution comprising a bromide salt;

electrolysis of a salt solution comprising a chloride salt and a bromide salt; and

admixing an aqueous solution comprising hypochlorous acid, formed by electrolysis of a salt solution comprising a chloride salt, with a salt solution comprising a bromide salt.

13. The process of any one of claims 9-12, wherein the converting step comprises:

admixing the generated salt solution with additional water to produce a diluted salt solution;

electrolyzing the diluted salt solution to form the aqueous solution.

14. The process of any one of claims 9-13, further comprising measuring at least one of a residual oxidant content, a pH, a free available halogen content, and an oxidation reduction potential of the treated treatment fluid, and adjusting at least one of a volumetric ratio of the aqueous solution to the treatment fluid and a contact time based upon the measured at least one of a residual oxidant content, a pH, a free available halogen content, and an oxidation reduction potential.

15. The process of any one of claims 9-14, further comprising treating the water prior to the use of the water in at least one of the generating step and the converting step, wherein the treating comprises at least one of filtering, softening, heating, and cooling.

11. A method of servicing a wellbore, comprising:

transporting a portable tank containing a quantity of one or more salts to a well site to be serviced;

generating a salt solution by passing water through the portable tank to dissolve a portion of the salt;

converting the salt solution to an aqueous solution comprising one or more oxidants via electrolysis;

contacting the aqueous solution with a treatment fluid to form a treated treatment fluid; and

providing the treated treatment fluid for placement into the wellbore.

12. The process of claim 11, wherein the salt comprises at least one of an alkali metal halide, an alkaline earth metal halide, and a transition metal halide, and wherein the one or more oxidants comprise one or more of ozone, hydrogen peroxide, hypochlorite, hypochlorous acid, chlorine dioxide, hypobromous acid, bromine, and chlorine.

16. A portable system for disinfecting water, comprising:

(a) a fluid connection for connecting to a water supply;

(b) a treatment system for conditioning the water supplied;

(c) a tank for admixing at least a portion of the conditioned water with one or more salts to form a salt solution;

(d) at least one electrolytic oxidant producing unit for converting at least a portion of the salt solution to an aqueous solution comprising mixed oxidants;

(e) a fluid connection for transporting the aqueous solution for contact with a fluid to be disinfected.

17. The system of claim 16, further comprising at least one of:

(f) one or more tanks for storing the aqueous solution;

(g) an acid supply tank for supplying acid to periodically clean the at least one electrolytic oxidant producing unit;

(h) a sampling system for sampling the fluid following contact with the aqueous solution;

(i) a process returns tank for accumulating materials fed from one or more of the treatment system, the tank for admixing, the electrolytic oxidant producing unit(s), the one or more tanks for storing, the acid supply tank, the sampling system; and

piping, pumps, and equipment associated therewith;

(j) a fluid connection for transporting accumulated materials from the process returns tank;

(k) one or more fluid conduits for transporting treated fluid to the sampling system;

(l) a control system for controlling a feed rate of the aqueous solution.

18. The system of claim 16 or claim 17, wherein the treatment system for conditioning the water comprises at least one of:

(i) a filter for reducing a solids content of the water;

(ii) a water softening system for reducing a metals content of the water; and

(iii) a heat exchanger for adjusting a temperature of the water.

19. The system of any one of claims 16-18, wherein the at least one electrolytic oxidant producing unit is in an enclosure having a filtered air cooling system.

20. The system of any one of claims 16-19, wherein the system is modular.

21. The system of any one of claims 16-20, further comprising one or more communication conduits for receiving a signal with or sending a signal from the control system from or to a local or remote source.

22. The system of claim 21, wherein the signal provides at least one of:

control system inputs or outputs for remote monitoring or operational control;

at least one of a residual oxidant content, a pH, a free available halogen content, and an oxidation reduction potential of the treated fluid;

a flow rate of at least one of the fluid to be disinfected, a treatment fluid precursor, and the treated fluid; and

a property of at least one of the fluid to be disinfected, a treatment fluid precursor, and the treated fluid after contact of the aqueous solution with the fluid to be disinfected.

23. The system of claim 21 or claim 22, wherein the control system is configured to determine a feed rate of the aqueous solution, adjust a feed rate of the aqueous solution, and/or control the feed rate of the aqueous solution, both in the presence of and absence of receiving or sending the signal with the control system from or to the remote source.

24. The system of claim 23, wherein the control system is configured for at least one of:

receiving a signal to adjust a system input or output from the remote source;

transmitting process data to a remote source monitoring the disinfecting process;

receiving a signal indicating at least one of a residual oxidant content, a pH, a free available halogen content, and an oxidation reduction potential of the treated fluid;

receiving a signal indicating a flow rate and/or composition of at least one of the fluid to be disinfected, a treatment fluid precursor, and the treated fluid;

receiving a signal indicating a property of at least one of the fluid to be disinfected, a treatment fluid precursor, and the treated fluid after contact of the aqueous solution with the fluid to be disinfected;

determining with the control system an aqueous solution flow rate using feedforward and/or feedback control based upon the signals received; and

generating and/or sending a treatment report.