A NOVEL LABORATORY TEST METHOD TO DETERMINE FILM PERSISTENCY OF BATCH INHIBITORS USED TO MITIGATE TOP OF THE LINE CORROSION

Batch inhibition treatment of oil and gas pipelines is one of the options used to treat top of the line corrosion in CO₂/H₂S containing wet hydrocarbons. The treatment efficiency largely depends on the inhibitor performance and the treatment frequency. The later is seldom determined based on the inhibitor film persistency among other operations-related constraints. It is within this framework that the present study is targeted to present a new laboratory test method to assess the performance of batch corrosion inhibitors and predict their film persistency. The newly designed apparatus offers several advantages over the commonly used ‘dip and drip’ method, including building the inhibitor film in-situ, applying a chosen wall shear level during the building and the stripping steps, monitoring the persistency through LPR measurements of the corrosion rate, replenishing the fluids at a chosen frequency through a computer controlled device and providing weight loss coupons for localized corrosion assessment. The method has been applied and is illustrated to demonstrate the capabilities and the dynamics of the new set up.