Paul A. Hsieh

It was the turning point for the worst oil spill in our nation’s history.

On July 15, 2010, a 75-ton containment cap was placed on the Deepwater Horizon oil well, stopping the flow of oil from gushing into the Gulf of Mexico for the first time in 86 days.

Even with this success, it was still an extremely tense time. Government engineers, often disagreeing with officials from well owner British Petroleum (BP), were not sure if the cap would hold or whether it would cause the well to rupture from beneath the seabed and result in a bigger and harder-to-control disaster.

A six hour pressure test to determine the cap’s viability was ambiguous, and the majority of the government science advisors concluded that without additional information, it would be too dangerous to leave the well shut in. As a result, the government would direct BP to reopen the well the next day, which would have caused the oil to once again flow back into the Gulf.

As the anxiety mounted, U.S. Geological Survey (USGS) Director Marcia McNutt turned to Paul Hsieh, a research hydrologist with a specialty in underground water reserves, not oil, who had been in Houston studying the well for several weeks along with other USGS scientists. USGS colleague Steve Hickman had taken a cellphone picture of a computer screen showing the rising pressure in the well, and sent it to Hsieh.

Working through the night from his office in California, Hsieh relied on the mobile phone photo of the well’s pressure curve and a modified version of his reservoir modeling software to do his complex calculations. After hours of analysis, Hsieh concluded the cap would hold and was not leaking beneath the Gulf surface, a decision that was accepted on July 16. As a result, the cap remained in place, and the well never spilled another drop of oil.

“Paul’s model provided the confidence for the government team to keep the cap and stack closed,” said Rear Adm. Kevin Cook, director of prevention policy, U.S. Coast Guard. &ldquoIt was a real game changer.”

“Paul was the one person who had the piece to the puzzle,” Cook added. “He had credibility earned over years as a scientist. I don’t think that it could have been done by just anyone.”

McNutt said she had full faith in Hsieh’s evaluation.

“Paul performed in the heat of the moment using this incredibly complex, detailed model. It not only fit the pressure data and the shape of the curve as the pressure rose, but also showed that the shape of the rise in pressure was consistent with the integrity of the well. That was the deciding factor,” McNutt said.

Hsieh said he was acutely aware that the stakes were enormous. He said he spent the entire night checking and re-checking his numbers to ensure that he correctly converted the oil industry’s measurement units to the metric system for his reservoir modeling codes.

“I knew that making one little error in conversion would give me the wrong answer,” Hsieh said. “In the back of my mind, I remembered an incident where NASA lost a Mars probe because the engineers and contactors were working in two different units.”

“I wasn’t going to let that happen,” he added.

After Hsieh’s initial presentation, he returned to Houston for the next few weeks to continue to model the rise in oil pressure as the well remained shut. Hsieh worked closely with BP scientists who also were modeling the pressure, which Hsieh said at the beginning was “stressful and tension-filled, but became increasingly collegial as time went on.”

The continued modeling by Hsieh and BP led Energy Secretary Steven Chu to see a consistent picture that the cap was working.

“Paul played a critical role in developing that picture,” Chu said.

Hsieh also used the data he developed to calculate the total amount of oil leaked into the Gulf of Mexico, a controversial issue because there had been conflicting reports throughout the environmental disaster. His calculation of 4.9 million barrels of oil spilt is the number that the government will use to base BP damages on, according to McNutt.

Originally from Hong Kong, Hsieh is a naturalized American citizen and has worked for the federal government for 33 years.

“I benefitted from the best of American society, and I went into public service, because it is the best way to use my skills and express my appreciation to the U.S. for adopting me as a citizen,” he said.

While not an expert on oil, Hsieh said there are many parallels to his work on water issues.

“Water and oil are both fluids. Oil seeps through the ground more slowly, but you can apply the science of water to oil,” said Hsieh. “Working on the oil spill is something I never expected.”

McNutt said Hsieh always had been recognized as an outstanding scientist by his peers in the research community, but he “never had an opportunity like this where his expertise was exactly what was needed to come in and save the day.”

“Anybody can be a hero, but there has to be that opportunity that you see and seize. This was Paul’s shining moment,” she said.