US Patent 11685856 Branched polyethyleneimine (B-PE) as oilfield metal naphthenate inhibitors

Relatively low molecular weight, branched polyethyleneimine (B-PE), a specific class of polyamine, has been shown to be effective at inhibiting the formation metal naphthenate precipitate (MNP) in systems and fluids that include an organic phase and an aqueous phase where the system or fluid further contains metal ions and tetra acid, and in particular the addition of low molecular weight, B-PE molecules prevents the formation of metal naphthenate precipitates/deposits in the fluids. Inhibition of alkali earth metal naphthenates (e.g. calcium naphthenate) and alkali metal naphthenates (e.g. sodium naphthenate) are particular non-limiting embodiments.