When it comes to harsh conditions that impact oil and gas equipment, sour gas (H2S) is particularly unforgiving. Its hydrogen sulfide content aggressively erodes tubes and pipes, leading to stress cracks that cause leaks and costly repairs. Fortunately, our Nedox coating is up for the challenge. Here’s how Nedox recently overcame sour gas attack for a manufacturer of gas separators in completed gas wells.

One completed gas well at an airport contained a particularly harsh sour gas with elevated sulfide levels in its stream. To combat the aggressive gas, the customer lined the separator with three layers of polypropylene and polyethylene. During tube installation, however, the linings suffered cracking and the sand in the gas eroded the plastic. These threats allowed the gas to attack the inner diameter of the tubing, creating a hole and ultimately causing a leak. Shutting down the well to replace the tubes would have been a substantial expense.

We coated the outer diameter with a nickel-based Nedox® coating — from 0.001 to 0.0015-inch thick — and the inner diameter with a Nedox that contains an additional polymer surface treatment. The manufacturer then applied paint to the outer diameter.

Our Nedox family of surface treatments is well suited for demanding oil and gas environments, and it offers a wide operating temperature range. Well known for its chemical resistance, Nedox offers superior protection against corrosion and wear, in addition to exceptional friction reduction properties. Nedox offers hardness up to 68 Rc and maximum salt spray resistance.

Seven months after the tubes were coated and installed, the airport’s inspector noticed some surface rust on some other parts and decided to remove the tubes. During removal, they noticed the inner diameter of the tubing had no damage and thus kept the remaining tubes in place. One of the tubes that was removed was an elbow. When the customer bisected the tube, we used copper sulfate to demonstrate that the Nedox coating was undamaged.

With these proven results, we coated the tubes for additional gas separators housed inside metal buildings. Not only is Nedox protecting the gas separator tubes with no reported problems, it is outperforming conventional epoxy coatings used on other separators at the site.

Ensure Maximum Reliability for Sour Gas Applications

As energy reserves become harder to access, sour gasses will pose a greater risk to oil and gas equipment reliability. As this successful application shows, even aggressive chemical attacks and the threat of wear can be overcome with a surface treatment engineered to impart the right properties to withstand sour gasses. Nedox coatings create sealed surfaces with hardness and density that match or surpass those of more expensive, corrosion-resistant metals to ensure maximum reliability in harsh oil and gas environments.

For more information about Nedox surface treatments, visit our coatings page.