Open AccessINFLUENCE OF THE ANIONIC COMPOSITION AND ACID GAS CONTENT IN FORMATION WATERS OF PERM KRAI FIELDS ON CORROSION INHIBITOR EFFECTIVENESS
Author(s) -
Aleksandr N. Ladygin
Publication year - 2020
Publication title -
vestnik permskogo nacionalʹnogo issledovatelʹskogo politehničeskogo universiteta. geologiâ, neftegazovoe i gornoe delo
Language(s) - English
Resource type - Journals
eISSN - 2305-1140
pISSN - 2224-9923
DOI - 10.15593/2224-9923/2020.2.9
Subject(s) - corrosion , chloride , electrolyte , sulfide , chemistry , hydrogen sulfide , acid gas , gas composition , environmental chemistry , formation water , anaerobic corrosion , metal , metallurgy , inorganic chemistry , materials science , geology , petroleum engineering , electrode , sulfur , physics , thermodynamics
In the course of hydrocarbon deposit development, formation water starts entering the wells over time. An increasing produced water volume has a negative impact on economic indicators of oilfield developments and leads to other hazardous consequences, such as equipment corrosion. Downhole equipment corrosion causes largest financial losses, since well accidents entail expensive repairs. Therefore, it is critical to prevent the equipment corrosion. The study considers main properties and composition of formation waters. Based on an overview of open literature sources, we analyzed the impact of Cl–, SO4 –2, HCO3 – anions contained in the formation waters on corrosion process kinetics at the phase interface between metal (electrode) and water (electrolyte). The study also discusses the results of researches on the influence of dissolved acid gases (H2S and CO2) on corrosion mechanisms and rates. An influence of pH value on the corrosion rate is considered. Contents of various salts in the formation waters contribute to the complexity of corrosion processes occurring in real conditions. Presence of aggressive environments can accelerate corrosion in some instances, but sometimes it can slow it down; this fact also affects the inhibitor protection effectiveness. Based on laboratory analysis data, effectiveness of using the corrosion inhibitor in the formation waters with different compositions and properties is assessed. It has been established that presence of a mix of aggressive components – chloride ions and hydrogen sulfide – in the formation waters causes hydrogen sulfide corrosion inhibition and reduction of chloride corrosion rate. Presence of dissolved salt ions and acid gases in the formation waters improves effectiveness of the corrosion inhibitors due to strong passive films formed on steel equipment surfaces.