Systems and methods of surface logging a well using a plurality of polymeric taggants distinguishable from each other include adding each of the plurality of polymeric taggants to a circulating drilling fluid while drilling the well in a repeating sequence and taking a sample drill cuttings carried by the circulating drilling fluid.

A process for detecting oil or lubricant contamination in the production of an article by adding a Stokes-shifting taggant to an oil or lubricant of a machine utilized to produce the article or a component thereof, irradiating the articles produced with a first wavelength of radiation, and monitoring the articles for emission of radiation at a second wavelength. The taggant can be in the form of a composition containing a Stokes-shifting taggant, which absorbs radiation at a first wavelength and emits radiation at a second wavelength, different from said first wavelength, dissolved or dispersed in an oil or lubricant.

A process for detecting oil or lubricant contamination in the production of an article by adding a Stokes-shifting taggant to an oil or lubricant of a machine utilized to produce the article or a component thereof, irradiating the articles produced with a first wavelength of radiation, and monitoring the articles for emission of radiation at a second wavelength. The taggant can be in the form of a composition containing a Stokes-shifting taggant, which absorbs radiation at a first wavelength and emits radiation at a second wavelength, different from said first wavelength, dissolved or dispersed in an oil or lubricant.

A compound of formula (I):

##STR00001##

wherein p is at least 1, n is at least 1 and less than or equal to p; Ar is a polycyclic aromatic moiety, R.sup.1 is hydrogen or an optionally substituted hydrocarbyl group and each of R.sup.2, R.sup.3 and R.sup.4 is independently an optionally substituted hydrocarbyl group, provided that at least one of R.sup.2, R.sup.3 and R.sup.4 has at least 6 carbon atoms.

The invention concerns a method of marking a hydrocarbon liquid comprising the ##STR00001##
step of adding to said liquid, as a tracer compound, a compound of Formula I or Formula II:
wherein at least one of R.sup.1-R.sup.6 in Formula I and at least one of R.sup.7-R.sup.14 in Formula II is selected from: i. a bromine or fluorine atom; ii. a partially or fully halogenated alkyl group; iii. a branched or cyclic C.sub.4-C.sub.20 alkyl group; iv. an aliphatic substituent linking two positions selected from R.sup.1-R.sup.6 in Formula I to one another or two positions selected from R.sup.7-R.sup.14 in Formula II to one another; or v. a phenyl group substituted with a halogen atom, an aliphatic group or halogenated aliphatic group
and none of R.sup.1-R.sup.6 in Formula I and none of R.sup.7-R.sup.14 in Formula II being a sulphonate group or COOR.sup.15, where R.sup.15 represents H, C.sub.1-C.sub.20 alkyl, C.sub.2-C.sub.20 alkenyl, C.sub.2-C.sub.20 alkynyl, C.sub.3-C.sub.15 cycloalkyl or aryl.

A marking method which is a method of marking a product having a distillation range is disclosed. The method comprises the step of adding to said product a first marker, a second marker and optionally one or more further markers. Each marker has a distillation range including a minimum boiling point (Min BP), a maximum boiling point (Max BP) and a maximum distillation boiling point (Max DBP) which is the temperature at which the maximum volume of the marker distils. Each marker has a different distillation range from each other marker and at least one marker has a Max DBP which is within the distillation range of the product. The first marker has a distillation range in the marked product which extends over the whole of the product distillation range.

A method for surface logging a well uses a plurality of polymeric taggants distinguishable from each other. The method includes selecting the polymeric taggants that have ceiling temperatures that do not interfere with pyrograms from source rock decomposition and adding each of the plurality of polymeric taggants to a circulating drilling fluid in a sequence while drilling the well. A sample of drill cuttings carried by the circulating drilling fluid is then taken. The method also includes measuring, using pyrolysis-gas chromatographymass spectrometry, concentrations of individual polymeric taggants attached to the drill cuttings in the sample and analyzing, using pyrolysis-gas chromatographymass spectrometry, properties of the drill cuttings. A depth associated with the sample is identified based, at least in part, on the measured concentrations of individual polymeric taggants and on the sequence.

A detection device for detecting a marker in a liquid, comprising a reaction chamber, provided with a thermosensitive sensor, wherein said reaction chamber comprises an photopolymer capable of releasing or generating a chemical species that is capable of undergoing or initiating an exothermic or endothermic chemical reaction with a marker present in the liquid.

A method for the detection of adulterated gasoline in a sample is disclosed. The method includes contacting a sample with an immobilized molecular probe, the immobilized molecular probe having a photoluminescence which is environmentally sensitive; collecting the photoluminescence from the immobilized molecular probe; and determining whether the photoluminescence is indicative of adulterated gasoline. A test strip for the detection of adulterated gasoline in a sample is also disclosed, including an immobilized molecular probe embedded in a substrate and/or immobilized to the substrate, the immobilized molecular probe having photoluminescence which is environmentally sensitive to adulterated gasoline. The method and test strips are designed to be robust, portable, and within the capabilities of untrained personnel.

A method of fuel analysis comprising subjecting a fuel sample comprising a fuel marker and a fuel matrix to fluorescence spectroscopy to generate a measured emission spectrum comprising a first spectral component (type and amount of marker in sample), a second spectral component (spectral perturbation), and a third spectral component (matrix fluorescence); deconvoluting the measured emission spectrum to yield a deconvoluted measured emission spectrum (first and second spectral components) via removal of third spectral component; decoupling the deconvoluted measured emission spectrum to yield a corrected emission spectrum (first spectral component) via a projection function which orthogonally projects the deconvoluted measured emission spectrum onto a subspace devoid of the second spectral component; and determining the amount of fuel marker in the fuel sample from the corrected emission spectrum. The method of fuel analysis comprises temperature corrections.