| 摘要 |
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.
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