Exxon failed to find oil off Alaska’s north coast.

Exxon said it plugged a $45-million exploratory well, the first one drilled in its search for oil that may have migrated out of the nearby Mukluk prospect, which oil companies abandoned last year after spending $1.6 billion on leasing rights and drilling expenses. Geologists had predicted that the oil they thought was in the Mukluk formation had migrated about 50 miles to the northwest, where Exxon was drilling. The site is about 115 miles northwest of Prudhoe Bay. Exxon said it will drill a second well, off in another direction from its platform, to further evaluate the prospect.