Selection of effective corrosion inhibitors for bischofite solutions and simulated medium of formation waters

Abstract

Questions of the corrosion inhibitors selection for protection of oil-field pipelines have been studied in the article. Results of research of technological and anticorrosive properties of the corrosion inhibitors in mediums simulating industrial environments are presented. The methodological approaches to selection of the corrosion inhibitors on a stage of laboratory experiments on an example of Kaverdinsky gas-condensate deposites have been described. It was found that all the surfactants tested in the simulated medium of the formation waters show a protective effect of more than 90% with a dosage of 1 g/dm 3 . It is recommended to use bischofite solution with a mass fraction of 24% MgCl2 and corrosion inhibiting 0.1% КI-1M admixture to protect industrial gas pipelines from carbon dioxide corrosion. This composition provides a degree of corrosion protection to 99.6%. The results of industrial tests confirmed the effectiveness of complex system -bischofite solution with a mass fraction of 24 % MgCl2 and addition of 0.1% KI-1M corrosion inhibitor. The cationic surfactants KI-1M, St, SRK and amphoteric surfactants EM and KAPB effectively protect in simulating medium and provide a degree of protection from carbon dioxide corrosion to 91.2-98.9%.

The use of bischofite in the gas industry as an inhibitor of hydrate formation

“…One of the main parameters influencing the corrosion rate is the ionic composition of the aqueous phase [4]. The main component of formation waters of North-Eastern Ukraine is sodium chloride NaCl [7]. Therefore, a solution of 0.5 M NaCl + 3 g/dm 3 CH 3 COOH in distilled water was chosen as the model medium for model formation water.…”

“…Corrosion studies were carried out in a thermostatic installation (figure 2) The installation is designed at the All-Union Scientific Research Institute of Natural Gases and Gas Technologies (VNIIGAZ) for determination of corrosion rate in the simulated conditions of industrial pipelines [7]. It is a glass vessel in which the test solution was poured and a fluoroplastic cylinder with witness samples and a propeller stirrer was placed.…”

“…Protective effect of test reagents in bischofite solution (Z) was calculated by the equation (2) [7]:…”

“…Problem statement World and domestic practice shows that one of the simplest, most effective and in many cases cost-effective methods of combating the processes of hydrate formation and corrosion is the use of inhibitors. [7,8]. According to the data of the feasibility study on the use of reagents, technologies based on the use of complex inhibitors are more efficient.…”

“…Inhibitors for industrial piping systems must have certain technological and protective properties. For example, hydration inhibitors should lower the hydration temperature by more than 25 ℃, corrosion inhibitors should have high protective properties in the water and vapor phases (not less than 85% of total corrosion), not to have a negative impact on technological processes [7].…”