Patent ID: 7703516

Claim:
A method for stimulating an oilfield, comprising the steps of: a) injecting at least two inflow fluid streams into at least two production zones of an oil producing well linked to the oilfield, respectively, or into at least two oil producing wells, respectively, wherein at least two scale inhibitors having detectable moieties are introduced into the at least two zones or wells, respectively, wherein each of the at least two scale inhibitors corresponds to a different zone or well, wherein the at least two scale inhibitors are different from each other, said at least two scale inhibitors comprising different detectable moieties that can be distinguished by analysis; b) displacing the oil; c) combining at least two outflow streams from the at least two zones or wells to form a combined outflow stream, d) recovering the combined outflow stream of fluid comprising the oil and amounts of the at least two scale inhibitors; and e) measuring the amounts of the at least two scale inhibitors in the combined outflow stream of fluid, or of a fluid derived therefrom.