Occurrence and Accumulation of Oil in Laredo District, Texas

Abstract

During the past few years the Laredo district of South Texas has come into prominence as one of the outstanding shallow oil-producing districts of the United States. The oil is recovered chiefly from shore-line sands of Jackson age, which occur at depths ranging from 160 to 3,500 feet. Accumulation of the oil therefore is in structures primarily of stratigraphic origin, that is, in buried shore-line sands. However, southeastward plunging folds, having axes approximately at right angles to the Jackson strand lines, and normal faults, with strikes oblique or transverse to the strand lines, are ordinarily either essential or important contributory factors in effecting accumulation, especially in the larger and more extensive fields.