The oil refinery in St. Paul Park will have its fourth owner in six years after Tesoro Corp. completes its $4.1 billion purchase of Western Refining.

El Paso-based Western had taken ownership of the St. Paul Park refinery just last June with its buyout of Northern Tier Energy. Earlier this month, San Antonio-based Tesoro announced it would purchase Western and its three refineries in Texas, New Mexico and Minnesota — the largest deal in the oil refining business since 2011.

The sale includes SuperAmerica, a leading Minnesota fuel and convenience store brand whose stations have long been supplied by the St. Paul Park refinery.

There are 277 SuperAmerica outlets in Minnesota, Wisconsin and South Dakota, 168 of which are owned by Western, while the rest are franchised. Western also owns the SuperMom’s bakery in St. Paul Park, which supplies SuperAmerica stores.

Brendan Smith, a Tesoro spokesman, said it’s “too early to speculate” on any plans Tesoro may have for the St. Paul Park refinery and the SuperAmerica brand.

“We are pretty excited about the potential here, and we are interested in growing our brand portfolio in different regions,” he said.

The St. Paul Park plant, built in 1939, is the state’s oldest refinery. It has been undergoing more than $100 million in renovations during the past two years.

Western Refining, which did $10 billion in sales in its most recent fiscal year, had a significant ownership interest in Northern Tier Energy since 2013. Arizona-based Northern Tier was formed when two private equity groups jointly purchased the St. Paul Park refinery from Marathon Oil in 2010.

Tesoro, with $29 billion in revenue in its most recent fiscal year, was the nation’s seventh-largest oil refinery at the beginning of 2016, according to the U.S. Energy Information Administration. The combination with Western Refining should make it the fifth-largest. Tesoro currently has seven refineries, including two in North Dakota.

The company already has a significant presence in Minnesota through its marketing operation, which sells fuel to wholesalers. Tesoro effectively supplies fuel to 250 branded fuel outlets in Minnesota, which operate under such retail banners as Shell, Exxon, Mobil and ARCO, as well as under the Tesoro brand, according to federal securities filings.

The St. Paul Park refinery gets crude oil from Canada and North Dakota, and the majority of its output goes to SuperAmerica outlets and Marathon Petroleum-branded convenience stores.

The plant has a capacity of about 98,000 barrels per day, reflecting upgrades made since 2011, when it had 77,000 barrel-per-day capacity. St. Paul Park hosts the smaller of Minnesota’s two oil refineries. The largest, Flint Hills Resources in Rosemount, can process about 340,000 barrels per day and is owned by Wichita-based Koch Industries.