Protester blocked the oil fields over alleged neglect at the hands of the Colombian government and the multinational oil companies in the region, Colombia Reports said.
"The people want social investment, like healthcare, education and the creation of jobs," said journalist Emiro Goyeneche, who was at the protest.
Violence between protesters and police has been ongoing since Tuesday, Goyeneche said.
"The people don't want to fight," Goyeneche said, adding that authorities initiated the clashes. "But the people had to defend themselves."
President Juan Manuel Santos told state radio that the protests were illegal.
"Moreover there are accusations that these organizations are supported by guerrilla groups," he said.
Santos said he planned to travel to Arauca Saturday to assess the situation.