The U.S. is seeing the highest level of crude production since 1998, the Journal Record reports. Oklahoma currently ranks No. 5 nationally, and “unconventional” drilling in shale rock formations is fueling much of the boom.

Continental Resources is one of the main players in Oklahoma and in North Dakota’s Bakken formation. Warren Henry, vice president of investor relations at Oklahoma City-based Continental, said national oil production is driven by what is known as unconventional oil, drilled from tight shale rock formations.
Read more at: journalrecord.com