Story of big wells

In NE. Dimmit, SE. Zavala counties, approx. 75 miles southwest of San Antonio, the Big Wells field is developing as a fairly large, significant stratigraphic trap oil field. The San Miguel Sand of the Upper Taylor (Upper Cretaceous) is a section noted for tight sand conditions and small 5 to 10 well oil fields. Ranging from 5,300 to 5,700 ft in depth, with a minimum of 200 ft and possibly 440-ft oil column, the field was found by Sun Oil in Jan. 1969. First drilled in the N. part of the field, tight sand conditions were encountered casting doubt on the economics involved. Through the Superfrac (hot oil) method of treating, economical rates of production resulted. Southward of the original drilling much better sand conditions were encountered, resulting in full allowable flowing wells (142 bopd in March 1971). In mid-March, the field was 12 miles long and 3 miles wide. Ten rigs were operating in the field in March 1971. With 145 wells completed in mid-March, the E.-W. limits of the field are still not defined. Drilled on 80-acre spacing, approx. 250 to 300 wells are anticipated for the field. Daily production in March 1971 was between 14,000 to 15,000 more » bbl of oil. « less