| abstract |
A fluid identification system comprising a plurality of particles, each particle encapsulating therein at least one tracer material having an identifiable DNA, the at least one tracer material being encapsulated by an encapsulation material, wherein the particles are adapted to retain the at least one tracer material in an encapsulated form after exposure of the particles to a temperature of at least 75 °C and/or a pressure of at least 1000 psi (6.9 x 10 6 N/m 2 ). |