Patent ID: 9534166
Date: 2017-01-03
CPC Classifications: C07F,C08F,C09K,E21B

Claim:
1. A method for imparting scale inhibition in an oilfield, the method comprising the steps of: a) injecting at least two inflow streams of a fluid into at least two production zones of an oil producing well that is linked to the oilfield, or into at least two different oil producing wells that are linked to the oilfield, wherein scale inhibitor having detectable moieties is introduced into the oilfield and/or into the fluid, so as to be present in the two zones or wells, wherein two different scale inhibitors are introduced, one for each of the two zones or wells, said different scale inhibitors having different detectable moieties, such that these different scale inhibitors have distinct absorption maxima that can be determined by an absorption analytical method; b) displacing oil from the oil producing well; c) recovering an outflow stream of fluid comprising the oil; wherein at least two outflow streams, one from each of the two zones or one from each of the two wells, are combined before said recovering; and d) measuring the amounts of the different scale inhibitors present in the recovered stream of fluid, or in a fluid derived from the recovered stream of fluid, by an absorption analytical method; and wherein one of the two scale inhibitors is a polymer (P1) as obtained by polymerization of: in the presence of an hypophosphorous adduct of the formula (A1): wherein: X is H or an alkali metal, alkaline earth or ammonium, Y is an alkylene group, which may be linear or branched, having from 1 to 5 carbon atoms; and wherein the other one of the two scale inhibitors is a polymer (P2) as obtained by polymerization of: in the presence of an hypophosphorous adduct of the formula (A1): wherein: X is H or an alkali metal, alkaline earth or ammonium, Y is an alkylene group, which may be linear or branched, having from 1 to 5 carbon atoms, whereby the hypophoshorous adducts of the formula (A1) are identical or distinct.