the mid-continent oil field is a big area that has hundreds of oil fields in arkansas, kansas, louisiana, new mexico, oklahoma and texas. the area, which has various geological strata and diverse trap types, was discovered and used during the first half of the 20th century. most of the crude oil found in the onshore mid-continent oil field is the mixed base or intermediate type (a mix of paraffin base and asphalt base crude oil types).