Abstract: The invention provides for the use of at least one aromatic acid compound of formula i), or a salt thereof, as a water tracer; wherein n is 0, 1 or 2, R1 to R5 are each independently H, alkyl or alkoxy and wherein at least one of R1 to R5 is alkoxy. The invention further provides for a method of monitoring the flow of water within a structure having an inflow point and an outflow point, where the method comprises; a) introducing at least a one tracer of formula i) into said inflow point; b) collecting fluid at said outflow point; and c) measuring the presence and/or concentration of said tracer in said fluid collected at said outflow point over time.

Abstract: A family of organic tracers is proposed for single well chemical tracer tests, for example for the measurement of residual oil in petroleum reservoirs. The tracers consist of at least one ester of (hydroxyalkyl) benzoic acid of formula (I), wherein at least one of R1 to R5 is a hydroxy alkyl group —R7—OH and each of the remaining R1 to R5 groups is independently selected from H, F, Cl, Br, I, CF3CF2Cl, CFCl2, CCl3 and at least one of these remaining R1 to R5 groups is not H, R6 is selected from CH3, C2H5, C3H7, C4H9, CF3, CH2CF3, CCl3, CH2CCl3, CH2CHCl2, CH2CH2Cl, CH2CF3, CH2CHF2, CH2CH2F, CH2CH2CH2F, CH2CH2CHF2, CH2CH2CF3, CH2CH2CH2Cl, CH2CH2CH—Cl2, CH2CH2CCl3, C3H6F, C3H5F2, C3H4F3, C3H6Cl, C3H5Cl2, C3H5Cl3 or a halogenated (hydroxymethyl)phenol and R7 is selected from CH2, C2H4, C3H6, C4H8.

Abstract: The invention provides for the use of at least one aromatic acid compound of formula i), or a salt thereof, as a water tracer; wherein n is 0, 1 or 2, R1 to R5 are each independently H, alkyl or alkoxy and wherein at least one of R1 to R5 is alkoxy. The invention further provides for a method of monitoring the flow of water within a structure having an inflow point and an outflow point, where the method comprises; a) introducing at least a one tracer of formula i) into said inflow point; b) collecting fluid at said outflow point; and c) measuring the presence and/or concentration of said tracer in said fluid collected at said outflow point over time.

Abstract: A family of organic tracers is proposed for inter-well measurement of residual oil in petroleum reservoirs, as is their use as partitioning tracers in a petroleum reservoir. The tracers consist of at least one benzyl alcohol of formula i) wherein each of R1 to R5 is independently selected from H, F, CI, Br, I, CF3 CF2CI, CFCI2 and CCI3 and wherein at least one of R1 to R5 is not H.

Abstract: Biphenylmono- and polysulphonic acids and salts thereof, fluorenemono- and polysulphonic acids and salts thereof as well as p-terphenylmono- and polysulphonic acids and salts thereof may be used successfully as tracers for surveying, monitoring and/or measuring movements of aqueous fluids in aqueous and/or non-aqueous media. Said substances are especially suited for surveying or monitoring movements of fluids in oil wells or reservoirs as well as for fluid movements in hydrothermal reservoirs.