BP PLC said Monday it will replace 73 percent of the pipelines from the nation’s largest oil field and that production could be closed for weeks or months, crimping the nation’s oil supplies at a time of peak demand.

BP, the world’s second-largest oil company, began shutting down the pipelines on Monday and said it would replace 16 miles of the 22 miles of transit pipeline it operates in the Prudhoe Bay field following a leak discovered Sunday.