VIDALIA — An oil and gas company based in Dallas announced Friday they have made a $7 million purchase of the shallow rights for a Lake St. John oil field.

TriDimension Energy — known locally as Axis Onshore — bought the rights to the field, located in Concordia and Tensas parishes, that has produced more than 50 million barrels of oil since its discovery in 1942.

Until recent upswings in oil cost, much of that field was undeveloped or abandoned, TriDimension Chief Operating Officer Jamey Ryan said.

“The whole field has changed hands a number of times since 1942,” Ryan said. “We feel pretty comfortable that there are significant remaining oil reserves.”

But the recent rise in oil production costs gave TriDimension a reason to look to the St. Joseph field, Ryan said.

“At $85 a barrel, it’s kind of a new day,” he said.

TriDimension has approximately 20 employees locally, and has an office in Vidalia.