Shell is drilling in the Chukchi Sea. The semi-submersible Polar Pioneer “spudded” the Burger J well at 5 p.m. July 29, company spokeswoman Meg Baldino said. Meanwhile, an ice-management vessel sent to Oregon for repairs is now en route after police cleared protesters that were blocking the vessel.

“The Fennica is now safely on its way to Alaska and will join Shell’s exploration fleet in the Chukchi Sea — where the Transocean Polar Pioneer commenced initial drilling operations,” Baldino said in a statement. “We remain committed to operating safely and responsibly and adding to Shell’s long history of exploration offshore Alaska.

As the Polar Pioneer drills, Shell’s second drillship on the scene, the Noble Discoverer, is moored at the Burger V well location in the same area.

Until the Fennica arrives with a critical “capping stack” used to control an undersea blowout, the Bureau of Safety and Environmental Enforcement has given Shell permission to drill “top holes,” or the upper parts of wells that do not penetrate potential oil-bearing formations.

Shell may drill just one well at a time, although the second drillship can be kept nearby and ready to drill when the first vessel finishes a well. Federal rules prohibit simultaneous drilling by drill vessels within 15 miles, and Shell’s planned well locations, for this year, are nine miles apart.