Dual-purpose corrosion and kinetic hydrate inhibitors based on 3-acrylamidopropyl trimethyl ammonium copolymers

Abstract

Corrosion inhibitors (CIs) are cost-effective and efficient solutions to mitigate the corrosion and to protect the relevant assets in the oil & gas sector. The corrosion inhibitors have however the potential to dramatically impair the effectiveness of the kinetic hydrate inhibitor (KHIs) because of compatibility issues. Creating a copolymer with both CI and KHI qualities for a sour environment is a challenge. This study proposes a new copolymer with CI and KHI moieties: 3-acrylamidopropyl trimethyl ammonium chloride (AMPTMA) block copolymers with acryloyl and acrylamide type comonomers. The corrosion studies were carried out utilizing high-pressure high temperature (HPHT) rotating cage autoclave and electrochemical measurements under different laboratory (standard 3.5 wt% NaCl brine) and field simulated conditions. These copolymers provided corrosion inhibition efficiency of up to 90%, owing to their strong adsorption on the carbon steel surface. The type of comonomer used in copolymers appears to play a significant role in corrosion prevention and adsorption capabilities on the metal surface. Additionally, one of the copolymers demonstrated the effectiveness as KHI by holding a subcooling of 5.6 °C at 96 bar in a sour (H2S) environment. These findings provide evidence that AMPTMA based copolymers have the potential to work as dual-purpose inhibitors (KHCI) to mitigate corrosion and gas hydrate formation.