Aplicação de copolímero combinado com surfactantes para a prevenção de precipitação de carbonato de cálcio na indústria do petróleo

Abstract

The present work aimed to evaluate the use of poly (4-styrene sulfonic acid-maleic acid co-acid) (P (SS-AM)) and its supramolecular complexes with surfactants (sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB)) as scale inhibitors. The tests performed to study the inhibition efficiency of materials were based on the dynamic efficiency test, chemical compatibility test and the conductivity measurements. Inhibitor performance was evaluated by the minimum effective concentration (CME) under temperature, pressure and flow conditions like oil wells. In addition, the influence of temperature, salinity, concentration of Fe3+ ion and headspace volume on the precipitation level was also evaluated. The results showed that the P(SS-AM) is efficient and chemically compatible with the brines used, presenting 10 mg/L CME, at pH 6.5 and 100 ºC.Studies have shown that the efficiency of inhibitor P(SS-AM) is reduced at high temperatures (>100 °C) and in low salinity waters containing Fe3+ ions. The combination of P(SS-AM) with surfactants (SDS) resulted in the enhancement of the individual copolymer result, reducing its chemical incompatibility at temperatures above 100 ºC. As headspace volume increase, the rate of scale formation increased, indicating the evolution of the HCO3- to CO32- system. Finally, the results indicate that the scale inhibitors based on copolymer and their combination with surfactants may be an alternative to lower operating costs caused by inorganic scale deposition in oil wells.