Activity in the deepwater Gulf of Mexico ( GOM) is on the upswing post-Macondo, thanks partly to seven key technologies, a Chevron executive said during a keynote address at the Louisiana Gulf Coast Oil Exposition (LAGCOE) held in Lafayette in late October. Steve Thurston, vice president of Chevron North

America E&P Co., said the industry is on a “positive turnaround” following what he called the “dark days” after the Macondo blowout in 2010. He cited various examples of deepwater GOM progress, noting that Chevron has three deepwater GOM projects set for startup in 2014: Jack/St. Malo, Bigfoot and Tubular Bells.

All told, the company has seven producing wells and five major capital projects in the deep-water GOM. Chevron also now has five deepwater drillships in the GOM, up from three ships pre-Macondo.

The portion of the deepwater GOM known as the Lower Tertiary “is clearly the emerging large trend that we see in the future for the [GOM], at least for the next couple of decades,” Thurston said.

The Lower Tertiary is a challenging place to find and recover oil, because the deposits sit under “very large, mobile salt canopies,” with the drilling taking place in 4,000 to 7,000 feet of water, he said. Also, operators must drill through 10,000 to 15,000 feet of salt canopy and sediments to depths that can reach 30,000 feet.

On the plus side, the canopies have created trap systems that hold a thick zone for oil. One gross oil interval Chevron is developing in the trend is 1,400 feet thick. “It's got some very unique challenges … but I think some very large rewards,” he said.

While exploration and projects are on the rise in the GOM, production has yet to exceed pre-Macondo levels. Some of the newest production data in the deepwater GOM comes from Cascade and Chinook fields, Thurston said. Cascade has two wells producing 3,000 to 4,000 barrels per day, while Chinook has one well averaging 7,000 to 8,000 barrels per day.

Chevron has new information from Jack/St. Malo, where six wells have been drilled recently. Four have been completed, and two have had flowback. Thurston didn't share all the data from the wells, but said that during the wells' flowback, the company was able to reach its facility limitation of 13,500 barrels per day.

To succeed with deepwater GOM projects, Thurston said companies need to have a systematic framework for operational excellence and transfer “lessons learned” from one project to the next. But he also credited seven “big” technologies: Advances in seismic data acquisition and imaging; drilling efficiency via dual-gradient drilling; completion technology, including single-trip, multizone frac packs; in-well artificial lifts; sea-floor pumping; optimized water floods; and enhanced oil recovery.

Thurston said an enhanced single-trip multizone frac pack system saved 50 days of completion on one well. With the Jack/St. Malo project, where there are actually two sites nearly 25 miles apart served by one floating production unit (FPU), subsea pumping is crucial to effectively produce at that depth and distance from the central FPU. The subsea pumps for each drill center are powerful, Thurston said, at 3.5-megawatt units with an intake pressure of 13,500 psi.

Success also requires planning and long-term capital commitment. Even in the dark days of fall 2010, the company's top leadership approved three deepwater GOM projects totaling roughly $17 billion because it understood the long-term investment needed to succeed, he said. “We need to expect breakthroughs, we need to fund them, and then the key is that we need to fund it way before we need it.”

—Robert Michel

For more on offshore exploration and technology, see EPmag.com.

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