New Orleans, Louisiana (CNN) -- An abandoned well struck by a barge in southeastern Louisiana early Tuesday is still spewing a mixture of oil, gas and water, and it could take 10 days before it is capped.
That was the word Thursday from the U.S. Coast Guard, which is overseeing efforts to contain the well and limit environmental damage.
"They've got a better handle on it now," said Coast Guard spokeswoman Elizabeth Bordelon, after a Texas firm hired to cap the well worked overnight to study the leak and come up with plans to seal it.
Wild Well Control, Inc. of Houston, Texas, outlined the plan to authorities on Thursday.
Sealing the well will be difficult, because it's in a relatively shallow area in a lake off Louisiana's Barataria Bay. An array of barges and firefighting equipment will have to navigate those shallow waters.
"Before they could consider bringing in those barges, they basically needed a road map of where they're going," Bordelon said. "We don't want to wind up doing any more damage."
Once everything is in place, mud will be pumped into the well to seal it -- in an effort similar to the "static kill" planned for BP's crippled well in the Gulf of Mexico, although this work will take place on the surface because the wellhead is spewing directly into the air.
The well is classified as "orphaned" by the Louisiana Department of Natural Resources. But the last owner of record was Cedyco Corp. of Houston, and U.S. and state officials say Cedyco ultimately is responsible for containing it.
For now, the Coast Guard has tapped the Oil Spill Liability Trust Fund, which the federal government makes available for natural resource damage assessments.
Authorities are not sure exactly how fast or how much of the mixture of oil, gas and water has leaked. When it was in use, the well produced 33 barrels of oil a day.
The sheen from the spill now covers about six square miles of water.
In addition to Wild Well Control, another company, Environmental Safety and Health Inc., has been contracted for the cleanup.
So far, 32,900 feet of boom have been laid out to stop the mixture from spreading. Another 4,400 feet of absorbent boom have been arrayed to soak it up. About 150 people are involved in the cleanup, with crews working overnight. Skimming ships are being used to collect the oil and gas.
The barges that will be used in pumping mud into the well were due to arrive in the area Thursday night.
"Our No. 1 priority right now is containing the damage," Bordelon said.
The abandoned well was hit around 1 a.m. Tuesday, when a dredging barge that was being pushed by a tugboat struck the wellhead. The Coast Guard is investigating exactly how it happened.
CNN's Vivian Kuo, Erin Lowry, MaryLynn Ryan and Tristan Smith contributed to this report.