Corrosion of downhole equipment in hydrogen sulfur-containing environments

Abstract

Complications associated with the corrosive environment, according to JSC Orenburgneft, NK Rosneft for the period 01.01.2021, are among the prevailing ones at oil and gas production facilities and share the 1st place with the scaling factor - 26% of the complicated mechanized well stock. Downhole equipment failures due to corrosion account for 20% of the total number of fixed failures in 2020. By the type of exposure to a corrosive environment at the fields operated within the perimeter of Rosneft, JSC Orenburgneft, hydrogen sulfide and mixed corrosion (caused by simultaneous action of CO2 and H2S) are predominant. The article presents the calculated data on the physicochemical characteristics of aqueous solutions of H2S. The existing approaches for description of the mechanisms of hydrogen sulfide corrosion of oilfield equipment with examples of corrosive destruction at producing string are described A dynamic matrix of the various protection technologies and their applicability in hydrogen sulfide-containing environments is presented, which is used in the fields operated by PJSC NK Rosneft and filled according to the results of laboratory and pilot field tests. The criterions of attribution of equipment to abnormal fund on basis of classification of factors complicated exploitation and following determination of equipment category being used in localized norms of NK Rosneft are described.