Abstract: A method of monitoring a fluid is described comprising: introducing a tracer into the fluid and analysing the fluid to determine if the tracer is present in the fluid; characterised in that the tracer comprises luminescent carbon-based nanoparticles exhibiting a peak luminescence intensity at an emission wavelength of at least 500 nm. The method is in particular a method of monitoring a parameter of a hydrocarbon well, pipeline or formation. A use of a tracer and a tracer composition comprising carbon-based nanoparticles exhibiting a peak luminescence intensity at an emission wavelength of at least 500 nm are also described.

Abstract: An oil field chemical-carrying material comprising granulated particles is disclosed. The granulated particles comprise alumina. An oil field chemical is integrally incorporated into the granulated particle. The particles have been aged by heating the particles in a sealed or humid environment.

Abstract: A method of monitoring a parameter of a hydrocarbon well, pipeline or formation is provided. The method comprises introducing a tracer into the hydrocarbon well, pipeline or formation; producing a fluid from the hydrocarbon well, pipeline or formation; and analyzing the fluid to determine if the tracer is present in the fluid. The tracer comprises a halogenated alkoxylated-benzoic acid, an alkoxylated benzene sulfonic acid, a salt of a halogenated alkoxylated-benzoic acid or a salt of an alkoxylated benzene sulfonic acid.

Abstract: A method of monitoring a parameter of a hydrocarbon well, pipeline or formation is provided. The method comprises introducing a tracer into the hydrocarbon well, pipeline or formation; producing a fluid from the hydrocarbon well, pipeline or formation; and analysing the fluid to determine if the tracer is present in the fluid. The tracer comprises a halogenated alkoxylated-benzoic acid, an alkoxylated benzene sulfonic acid, a salt of a halogenated alkoxylated-benzoic acid or a salt of an alkoxylated benzene sulfonic acid.

Abstract: A method of monitoring a parameter of a hydrocarbon well, pipeline or formation is provided. The method comprises introducing a tracer into the hydrocarbon well, pipeline or formation; producing a fluid from the hydrocarbon well, pipeline or formation; and analysing the fluid to determine if the tracer is present in the fluid. The tracer comprises a halogenated thiophene carboxylic or sulfonic acid or a salt of a halogenated thiophene carboxylic or sulfonic acid.

Abstract: The invention concerns a tracer material for tracing fluid flows from a hydrocarbon reservoir. The tracer material comprises a plurality of separate agglomerates. The agglomerates comprise clusters of particles. The particles carry a tracer composition. A retaining material at least partially overlies the tracer composition. The retaining material retards the release of the tracer material so that the tracer is released at a more constant rate over a longer period than in the absence of the retaining material.