Abstract

Hydrogen induced damage to equipment in the form of hydrogen blistering, hydrogen induced cracking (HIC), stress oriented hydrogen induced cracking (SOHIC), hydrogen stress cracking (HSC) and sulfide stress cracking (SSC) is a major concern in oil and gas production facilities operating in a H2S (sour) environment. However, it is important to note that the mere presence of H2S (sour environment) is not a cause for concern. It is the activity of H2S in combination with the total system pressure, the pH of the environment, the CO2 content, and the chloride ion concentration that determines the corrosivity of the system. In addition, the composition, microstructure and heat treatment condition of the material of the equipment play essential roles in the propensity to cracking in such sour atmospheres.

The propensity to hydrogen damage (or risk rating) can be estimated by measuring the hydrogen flux (or permeation) through the material of the vessel. Recently, hydrogen permeation measurements were conducted on some selected vessels handling sour crude and gas in an oil and gas processing facility at the Kuwait Oil Company (KOC). Based on the ‘Risk Rating’ derived from the hydrogen permeation measurements, hydrogen damage was suspected in two of the vessels. Phased Array Ultrasonic Inspection of one of the vessels confirmed the presence of HIC thus validating the accuracy of hydrogen permeation measurements in predicting/detecting hydrogen damage. The present paper discusses the findings of the hydrogen permeation and ultrasonic inspection data.

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