Corroded oil pipeline with sulfide stress cracking.

Is Your Oil and Gas Infrastructure at Risk? The Truth About Sulfide Stress Cracking

Avery Sinclair in Tech & Innovation June 2025 • 4 min read.

"Uncover the vulnerabilities of P110 steel and how heat treatment can unexpectedly compromise its resistance to sulfide stress cracking."

In the relentless pursuit of efficiency and cost reduction, the oil and gas industry constantly pushes the boundaries of material science. One critical area of focus is the integrity of downhole tubulars, the backbone of drilling and production operations. These steel components face immense pressures and corrosive environments, making material selection and treatment paramount.

Sulfide stress cracking (SSC) is a notorious threat in this sector. This form of environmental cracking occurs when materials are exposed to hydrogen sulfide (H2S) under stress, leading to unexpected and potentially catastrophic failures. The presence of H2S turns aqueous solutions acidic, creating conditions ripe for SSC, especially in deep, high-pressure sour gas environments.

A recent study published in the Journal of Petroleum Science and Engineering sheds light on a counterintuitive twist: heat treatment, often used to strengthen steel, can actually increase its susceptibility to SSC under certain conditions. This article breaks down the study's findings and explores the implications for material selection and maintenance in the oil and gas industry.

The Unexpected Weakness: How Heat Treatment Changes the Game

Corroded oil pipeline with sulfide stress cracking.

The research focused on P110 steel, a common material for downhole tubulars, known for its high yield strength (minimum 110 ksi or 758 MPa). The goal was to determine if heat treatment could further enhance the steel's strength, allowing for thinner tubular walls, which would reduce costs and increase wellbore diameter for improved production rates.

Researchers tested P110 steel specimens with and without heat treatment, exposing them to a deaerated 3.5% NaCl solution containing 0.01 M Na2S2O3 (a source of H2S) at room temperature. The results were startling. Here’s what they found:

Untreated P110 Steel: Showed significant resistance to SSC in the test environment.
Heat-Treated P110 Steel: Displayed a marked susceptibility to SSC, failing much faster than the untreated samples.
Microscopic Analysis: Scanning electron microscopy (SEM) revealed intergranular propagation of stress corrosion cracks in the heat-treated steel, indicating a clear mechanism for the increased vulnerability.

These findings suggest that while heat treatment can indeed boost the overall strength of P110 steel, it also alters the microstructure in a way that makes it more vulnerable to the corrosive effects of H2S. This highlights the complexity of material selection and the need to consider the specific environmental conditions and potential failure mechanisms.

Protecting Your Assets: Key Takeaways for the Oil and Gas Industry

The study underscores the importance of a holistic approach to material selection and maintenance in the oil and gas industry. While high-strength steels offer cost and efficiency benefits, it's crucial to thoroughly evaluate their susceptibility to SSC and other environmental factors. Heat treatment should not be applied blindly but rather with a deep understanding of its potential impact on corrosion resistance. Further research is needed to explore alternative strengthening methods that minimize the risk of SSC in P110 steel and other critical materials. Regular inspections, rigorous testing, and adherence to industry best practices are essential for preventing costly failures and ensuring the safety of operations.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1016/j.petrol.2018.10.102, Alternate LINK

Title: The Susceptibility Of P110 Downhole Tubular Steel To Sulfide Stress Cracking In H2S And Nacl

Subject: Geotechnical Engineering and Engineering Geology

Journal: Journal of Petroleum Science and Engineering

Publisher: Elsevier BV

Authors: R. Rihan, B. Al-Wakaa, N. Tanoli, H. Shalaby

Published: 2019-03-01

Everything You Need To Know

What is sulfide stress cracking (SSC) and why is it a concern in the oil and gas industry?

Sulfide stress cracking (SSC) poses a significant threat in oil and gas operations due to the presence of hydrogen sulfide (H2S). H2S acidifies aqueous solutions, fostering an environment conducive to SSC, especially in high-pressure sour gas environments. SSC can lead to unexpected and potentially catastrophic failures in downhole tubulars and other critical components.

What were the key findings of the study regarding the effects of heat treatment on P110 steel's resistance to sulfide stress cracking?

The study revealed that untreated P110 steel exhibited significant resistance to SSC in the test environment. However, heat-treated P110 steel displayed a marked susceptibility to SSC, failing much faster than the untreated samples. Microscopic analysis showed intergranular propagation of stress corrosion cracks in the heat-treated steel, indicating a clear mechanism for the increased vulnerability.

How can heat treatment, a process intended to strengthen steel, increase the risk of sulfide stress cracking (SSC) in P110 steel?

Heat treatment, while often used to enhance the strength of P110 steel, can inadvertently alter its microstructure, making it more vulnerable to the corrosive effects of H2S. This can lead to a higher risk of sulfide stress cracking (SSC) and potentially catastrophic failures in downhole tubulars. This finding highlights the need for a comprehensive understanding of how heat treatment affects corrosion resistance.

What are some key steps that the oil and gas industry can take to protect their assets from the dangers of sulfide stress cracking (SSC), especially concerning P110 steel?

To protect oil and gas assets from sulfide stress cracking (SSC), a holistic approach to material selection and maintenance is crucial. Thoroughly evaluate the susceptibility of high-strength steels like P110 steel to SSC and other environmental factors. Avoid blindly applying heat treatment without understanding its potential impact on corrosion resistance. Implement regular inspections, rigorous testing, and adherence to industry best practices to prevent costly failures and ensure operational safety. Further research is needed to explore alternative strengthening methods that minimize the risk of SSC.

What did the microscopic analysis using scanning electron microscopy (SEM) reveal about the mechanism behind the increased vulnerability of heat-treated P110 steel to sulfide stress cracking?

Scanning electron microscopy (SEM) revealed intergranular propagation of stress corrosion cracks in the heat-treated P110 steel samples. This observation supports the conclusion that heat treatment alters the microstructure of P110 steel in a way that makes it more susceptible to sulfide stress cracking (SSC). The intergranular crack propagation suggests that the grain boundaries in the heat-treated steel are weakened, providing preferential pathways for crack initiation and growth in the presence of H2S.