Greta oil field, in the north-central part of Refugio County, was discovered by George E. Smith et al., May 5, 1933.
The field is in the shape of an irregular elongate oval measuring approximately 4 by 2.5 miles with its major axis extending N. 22.5° E.
The structure is almost flat on top with steep dips in the beds beginning at the periphery and extending in northeasterly, southeasterly, and southwesterly directions. There is the suggestion of a fault along the northwest side of the field.
The three pay horizons are the Catahoula, or 3,500-foot sand, the Heterostegina, or 4,400-foot (“Greta”) sand, and the Frio, or 5,900-foot sand.
At the end of 1934 there had been completed 186 oil wells with a total cumulative production of more than 5 million barrels.