BATON ROUGE, La. — A four-story containment dome is on its way to the site of the leaking oil well and when the structure is installed on Monday, BP officials hope the experimental procedure will help stem the flow of crude oil spewing into the Gulf of Mexico since an explosion rocked a drilling rig there 15 days ago.

For the first time in several days, due to light winds, crews were able to conduct a controlled burn in two of the most concentrated areas of oil. This effort came as officials started the day with some encouraging, albeit small news: engineers had succeeded in shutting off one of the three leaks from the damaged well late Tuesday night, BP said.

Though by itself the move will not reduce the amount of oil being released — estimated at 210,000 gallons a day — “it is from two locations now,” Doug Suttles, the chief operating officer of BP said at a news conference Wednesday afternoon in Robert, La.

Submersible robots, controlled remotely from a ship on the surface, were able to place a specially designed valve over the end of a leaking drill pipe lying on the sea floor in water about 5,000 feet deep, and stop oil from escaping at that point.