Magnetic nanoemulsions for fluid conductivity analysis in subsurface reservoirs

A method for analysing a fluid conductivity of a fluid network within an underground formation, the method comprising:

• injecting a nanoemulsion from a surface into the underground formation, the nanoemulsion comprising dispersed liquid nanodroplets in a carrier liquid, wherein the nanodroplets are stabilized within the carrier liquid by solid nanoparticles located at an interface between the dispersed liquid nanodroplets and the carrier fluid, the solid nanoparticles having an affinity to be wetted by both the dispersed liquid of the nanodroplets and the carrier liquid and comprising:
• a core comprising iron;
• and a polymer coating, and wherein the nanodroplets are configured to remain stable and dispersed while in the formation;
• and
• measuring a parameter of the nanodroplets after the nanodroplets have been injected into the underground formation to determine a fluid conductivity of the underground formation,
• wherein the nanoparticles are paramagnetic, and
• wherein measuring the parameter comprises:
• measuring magnetic properties of the nanoemulsion while applying a magnetic field to the solid nanoparticles aligning themselves to the applied magnetic field, and then removing the applied magnetic field from the solid nanoparticles losing their magnetic moment.