An Economic Comparison of Developments in the South Field Oil-producing Region of Mexico

Abstract

The producing formation in the South Field, or "Golden Lane"structure of Mexico, is a buried ridge of reef limestone of Comanchean ageoverlain unconformably with sediments of Upper Cretaceous, Eocene andOligocene. The structure extends in a long sweeping arc, with the convex sidetoward the west, from San Geronimo, Vera Cruz, to San Isidro, south of theTuxpam River, which it crosses at the town of Alamo. It is 52 miles long andaverages 3/4 mile in width. The surface of the producing formation of EI Abra limestone consists of aseries of minor parallel highs which are separated longitudinally by synclinaltroughs and laterally by structural saddles. The presence of these highs hasbeen of utmost importance in the development of the field, especially in recentyears when the salt-water level has risen above the synclines and confined theoil to the isolated highs. In many cases, faulty information and interpretationof the subsurface has resulted in drilling costly dry holes and salt-waterwells. Development The development of the Golden Lane was started by the Mexican Eagle Oil Co. in1906. San Diego No.3, usually known as Dos Bocas, the first producing well onthe structure, was completed on July 4, 1908. This well came in unexpectedlyfor an estimated daily production of 129,000 bbl., and, as the casing was notproperly set, the well flowed wild into the Tamiahua Lagoon, causing a loss ofseveral million barrels of oil. In flowing wild the well formed a crater whichcovers an area of 48 acres, out of which salt water and small quantities of gasstill flow. Casiano No.2, the Huasteca Petroleum Co., which yielded 200 bbl. ofoil daily, and which was completed in November, 1909, was the next producingwell to be drilled on the structure. In 1910, the same company completedCasiano No.7, with an initial production of 50,000 bbl. daily, and CasianoNo.1, which produced 200 bbl. daily. In the same year, the Mexican Eagle OilCo. completed its Potrero del Llano wells 1, 2 and 4, with initial productionsof 500, 400 and 100,000 bbl. respectively.