DELIVERY OF NANODISPERSIONS BELOW GROUND

• US 20110146974A1
• Filed: 12/18/2009
• Published: 06/23/2011
• Est. Priority Date: 12/18/2009
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Hartshorne, Robert Seth, Tan, Khooi Yeei, Tustin, Gary John
• Granted Patent: US 8,342,241 B2
• Time in Patent Office: Days
• US Class Current: 166/250.12
• CPC Class Codes: C09K 2208/10 Nanoparticle-containing well treatment fluids
• CPC Class Codes: C09K 8/035 Organic additives
• CPC Class Codes: E21B 43/25 Methods for stimulating production by vibrating earth formations E21B43/003
• CPC Class Codes: E21B 47/11 using tracers; using radioactivity

Abstract

Delivery of a substance to a subterranean location is achieved by suspending the substance as nanoparticles in a carrier fluid in which the substance is insoluble. The procedure may start by forming a dispersible powder composition, which is done by dissolving the substance in a solvent, emulsifying the resulting solution as the dispersed phase of an emulsion, and freeze-drying the emulsion to a powder. On mixing the powder with a fluid in which the substance is insoluble, any soluble constituents of the powder dissolve and the insoluble substance becomes a dispersion of nanoparticles of the substance. Then, the fluid containing the dispersed substance is pumped to the subterranean location. The dispersion of nanoparticles has surprising stability, facilitating transport to the subterranean location. At the subterranean location the dispersed nanoparticles may migrate into other fluid encountered there: more specifically a dispersed tracer substance may migrate from injected water into hydrocarbon in a hydrocarbon reservoir. Another possibility is that dispersion as nanoparticles enables interaction with other constituents of the fluid to be delayed until the subterranean location is reached: more specifically the fluid may contain polymer and the dispersed nanoparticles may comprise an agent which participates in cross-linking and consequent viscosification of the polymer.

Claims

1. A method of delivering a substance to a subterranean location comprising:

forming a dispersible powder composition by dissolving the substance in a solvent, emulsifying the resulting solution as the dispersed phase of an emulsion, and freeze-drying the emulsion to a powder;

mixing said powder with a fluid in which the substance is insoluble, thereby forming a dispersion of very small particles of the substance in the fluid, and

pumping the fluid containing the dispersed substance to the subterranean location.

2. The method of claim 1 wherein the substance is hydrophobic and the fluid in which it is dispersed is aqueous.

3. The method of claim 1 wherein the concentration in the dispersed substance in the fluid is not more than 1 wt %.

4. The method of claim 1 wherein the dispersed particles of the substance have a particle size not greater than 800 nanometers.

5. The method of claim 1 wherein the dispersed particles of the substance have a particle size in a range from 1 nanometer to 500 nanometers.

6. The method of claim 1 wherein, after the fluid has reached a subterranean location, the dispersed substance migrates into another fluid encountered at that location.

7. The method of claim 6 wherein the dispersed substance is a tracer and the method includes detecting the tracer in fluid produced from the subterranean reservoir.

8. A method of investigating flow in a subterranean reservoir where an aqueous fluid is being injected into the reservoir comprising introducing a water-insoluble tracer compound into the aqueous fluid as a dispersion and examining hydrocarbon produced from the reservoir for the presence of the tracer compound, thereby to detect contact between the injected aqueous fluid and hydrocarbon fluid in the reservoir.

9. The method of claim 8 wherein the dispersed particles of the tracer have a particle size not greater than 800 nanometers.

10. The method of claim 8 wherein the dispersed particles of the tracer have a particle size in a range from 1 nanometre to 500 nanometres.

11. The method of claim 8 wherein, after the fluid has reached a subterranean location, the dispersed substance interacts with one or more constituents of the fluid in which it was dispersed.

12. The method of claim 11 wherein the fluid contains a thickening polymer and the dispersed substance participates in cross linking of the polymer.

13. The method of claim 12 wherein the fluid contains an aldehyde or aldehyde precursor and the dispersed substance comprises a hydrophobic precursor for a phenolic compound.

14. A method of increasing the viscosity of an aqueous fluid containing thickening polymer by cross-linking the polymer, characterized by providing a cross-linking agent or precursor therefor as a dispersion of nanoparticles in the aqueous fluid.

15. The method of claim 14 wherein the dispersed particles of the cross-linking agent or precursor therefor have a particle size not greater than 800 nanometers.

16. The method of claim 14 wherein the dispersed particles of the cross-linking agent or precursor therefor have a particle size in a range from 1 nanometre to 500 nanometres.

17. The method of claim 14 wherein the fluid contains an aldehyde or aldehyde precursor and the dispersed nanoparticles comprise a hydrophobic precursor for a phenolic compound.

18. The method of claim 17 wherein the fluid contains a formaldehyde precursor.