HIC and SSC of Carbon Steel in High Partial Pressure CO2 Environments with Elevated H2S

Muhammad Firdaus Suhor,Ahmad Mustaza Ahmad Rusli,Azmi Mohammed Nor,Ahmad Zaki Abas,Mokhtar Che Ismail

doi:10.1051/e3sconf/202128702001

Muhammad Firdaus Suhor, Ahmad Mustaza Ahmad Rusli + Show 3 more

Open Access

https://doi.org/10.1051/e3sconf/202128702001

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Abstract

The Hydrogen Induced Cracking (HIC) and Sulfide Stress Cracking (SSC) behaviours of sour service and non-sour service carbon steel API 5L X65 were investigated under high pressure carbon dioxide environments, containing elevated amount of hydrogen sulphide (H2S); the test environments simulated offshore pipelines transporting full-well streams in high carbon dioxide (CO2) environments with elevated H2S concentrations. It was systematically studied under standard NACE condition and high pressure carbon dioxide field condition with variation in other key parameters (temperature, pressure and hydrogen sulfide concentration). The HIC and SSC were tested using a High Pressure and High Temperature (HPHT) Autoclave. The surface cracking morphology was analysed using Scanning Electron Microscopy (SEM), Ultrasonic Technique (UT) and Magnetic Particle (MP). The results showed that no cracks were detected in NACE standard and field-condition SSC tests for both sour service and non-sour services carbon steel. In HIC test, crack was detected on non-sour service carbon steel in NACE standard test while no crack was detected on field condition-based tests for both types of carbon steel.

Highlights

Pipelines made from carbon steel are susceptible to Hydrogen Induced Cracking (HIC) and Stress Cracking (SSC) in wet hydrogen sulfide environment in transporting large amount of hydrocarbon gas with CO2
The results showed that no cracks were detected in NACE standard and field-condition SSC tests for both sour service and nonsour services carbon steel
In HIC test, crack was detected on non-sour service carbon steel in NACE standard test while no crack was detected on field condition-based tests for both types of carbon steel

Summary

Introductıon

Pipelines made from carbon steel are susceptible to HIC and SSC in wet hydrogen sulfide environment in transporting large amount of hydrocarbon gas with CO2. The blistering damage tends to form parallel to the surface and to the direction of hoop stress Because of this, it usually does not become damaging until it either becomes extensive and affects material properties or gives rise to cracking that propagates into a weld or begins to go stepwise through the wall. Many researchers have reported on corrosion behavior of carbon steel in high partial pressure CO2 environment either in sweet or sour conditions [1-6], but none has reported on HIC and SSC in the environment containing both high CO2 and elevated H2S. This study investigated the HIC and SSC behaviour of sour service and non-sour service carbon steel API 5L X65 under high pressure CO2 environments, containing elevated amount of H2S, to simulate the condition of high CO2containing natural gas offshore pipeline. The surface cracking morphology was analysed using Scanning Electron Microscopy (SEM), Ultrasonic Technique (UT) and Magnetic Particle (MP)

Materials

C Cr Mn P

Equipment and Test Conditions

Results and Dıscussıon