Hungarian police officers arrest a Greenpeace activist wearing an ice bear costume on the roof of a local petrol station in Budapest on July 19, 2012, during a protest against the Shell Oil Company's plans to drill in the Arctic. (ATTILA KISBENEDEK/AFP/GETTY IMAGES)

Shell completed its drilling season off the Arctic coast of Alaska Wednesday, falling short of its original goal of drilling as many as six exploration wells.

The company said it drilled the top portions of two wells, the Burger-A well in the Chukchi Sea and the Sivulliq well in the Beaufort Sea, without attempting to penetrate deeper reservoirs that could hold oil. The company said that the work would “go a long way in positioning Shell for another successful drilling program in 2013.”

Each well was drilled to a depth of 1,400 feet.

For months in the runup to drilling, the company’s exploration plans aroused opposition from environmental groups and many Native Americans in Alaska, but the Obama administration nonetheless issued the drilling permits the company needed to begin work.

Alaska’s open-water season is limited to about four months. And though ice receded in the Arctic region overall, it lasted longer than anticipated in the area of the Chukchi Sea where Shell was planning to drill. Even after getting its final permit, Shell had to wait while a huge ice sheet passed by.

Shell’s season ended up being even shorter because of ­delays in retrofitting a spill containment barge so that it would pass Coast Guard inspection. Shell’s oil spill containment dome was later damaged during sea trials.

When time became too short to complete an oil exploration well before the end of the open water season, the Interior Department gave Shell permission to drill the tops of its planned wells and to set in place blowout preventers. Interior said that there was not enough time for Shell to try to drill down to reservoirs that the company hopes contain oil and natural gas.

“Despite almost unlimited resources and government agencies willing to bend over backwards for the company, Shell was still derailed by an obvious lack of preparedness,” said a statement issued by Oceana, an environmental group opposed to offshore drilling.

Although American Petroleum Institute officials have complained about the Obama administration’s pace of issuing federal permits, Shell had only praise for the administration on Wednesday.

“On the permitting front, what we experienced in the last 18-months, as a result of the White House working group, is a model of how offshore permitting could and should work — not streamlined, just accountable and efficient,” Shell said in a statement. It praised the Interior Department in particular.