Abstract: A treatment process for an aqueous phase which contains oil droplets, possibly of 10-50 nm diameter, in aqueous flow from a hydrocyclone separator, comprises bringing the water into contact with a surface subdivided into areas of differing surface energy and affinity for oil and such that when the surface is submerged in an aqueous phase, oil droplets adhere to it with an apparent contact angle in a range from 90 to 150 degrees. Areas of the surface may reduce their affinity for oil in response to an external stimulus causing controlled release of droplets adhering to the surface. The process may be used to remove oil droplets from water produced by an oil or gas well, after downhole oil water separation or after production at a at a well head, or used to coalesce droplets in such water to a larger size to enable conventional separation.

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. First a dispersible powder composition, is formed 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, the insoluble substance becomes a dispersion of nanoparticles which is pumped to the subterranean location. At the subterranean location a tracer dispersed as nanoparticles may migrate from injected water into hydrocarbon in a hydrocarbon reservoir. Another possibility is that the carrier fluid contains polymer and the dispersed nanoparticles comprise an agent which participates in cross-linking and consequent viscosification of the polymer at the subterranean location.

Abstract: A method of processing an aqueous fluid produced from a wellbore in order to collect or remove a minor constituent therefrom, comprises adding one or more solutes to the aqueous fluid so as to form an aqueous mixture which separates into two aqueous phases in contact with each other, with a first solute present at a greater concentration in the larger, first aqueous phase than in the second aqueous phase and a second solute present at a greater concentration in the smaller, second aqueous phase than in the first aqueous phase; while the compositions of the two phases are such that the said minor constituent preferentially partitions into the smaller, second aqueous phase so that the concentration of that constituent in the smaller second phase exceeds its concentration in the larger first aqueous phase. The second aqueous phase with the said constituent concentrated therein is then separated from the first aqueous phase.

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.