The nearly 2,700-mile Keystone oil pipeline was shut down Tuesday morning after it ruptured in North Dakota, halting the flow of thousands of gallons of crude oil from Canada to refineries in the U.S.

South Bow Corp. says it is in the “early stages” of gauging customer interest in capacity on a cross-border pipeline linking Alberta’s Hardisty oil terminal to U.S. oil markets in Oklahoma and along ...