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What’s the future of checking up on a pipeline miles below the surface of the sea? Turns out, it might be simply calling a doctor.
Just as radiologists use X-rays to look for broken bones inside the body, engineers are exploring the use of similar technology to see if it can spot microscopic cracks and corrosion in underwater pipelines.
Companies have been using X-rays to inspect solid structures and mechanical parts for decades. But bringing an entire pipeline into the lab would be a titanic undertaking. Worse, subsea pipelines are often set at depths of 10,000 feet where pressure can reach 300 atmospheres. That’s more than 4,400 pounds of pressure per square inch. Sunlight does not penetrate down to the watery “midnight” called the bathypelagic zone and temperature hovers around 4 degrees Celsius (40 Fahrenheit). “People didn’t really think that radiography would work subsea,” says Dan Scoville from the oilfield services firm Oceaneering International.
But engineers at GE Healthcare, GE Oil & Gas, Oceaneering and BP decided to take a second look. They took apart GE’s medical X-ray detector, which includes a fragile piece of glass the size of a computer screen and delicate electronics, and put it back together inside a high-tech rugged case designed to protect it from sea water and pressure. “Anything with air in it would be squished,” Scoville says.
The reconfigured detector fits inside a larger machine attached to a deep-sea submersible rig. The rig latches onto the pipeline like a handcuff, slides down its length, and takes X-ray snapshots at each step. “This is not what we normally do,” says mechanical engineer Karen Southwick who works at GE Healthcare. “X-rays are giving us an insight. You don’t know something’s wrong and then you see it. Whether it’s a small spill or a catastrophic one, this is hopefully preventing that. Ideally, we will be able to have data for every pipeline that’s in the water.”
The subsea X-ray detector has performed well in lab tests and could be soon at work in the cold, dark depths, keeping watch over hundreds of thousands of miles of pipeline. Says Scoville: “It’s all an adventure. We are going somewhere where we don’t go every day.”