The Cretaceous Golden Lane reef fields are in northeastern Veracruz state, east-central Mexico. They partly underlie the coastal plain and partly the adjacent submerged continental shelf of the Gulf of Mexico. This paper is concerned mainly with the offshore fields and, more specifically, with a 45-mi-long belt of the Golden Lane reef south of Arrecife Medio field.

For many years several geologists postulated that the spectacular Golden Lane fields are only one segment of an atoll whose eastern part is beneath the continental shelf of the Gulf of Mexico. This working hypothesis led to an extensive and detailed seismic exploration program which, complemented and integrated with the discovery of the fields herein described, confirmed the presence of the postulated atoll. In essence, the atoll is a Middle to Late Cretaceous feature with a maximum north-south diameter of about 85 mi and a minimum east-west diameter of about 40 mi.

The earliest seismic survey was begun in 1957, and the first discovery, Isla de Lobos No. 1-B, was completed on June 28, 1963. Several discoveries have been made since Isla de Lobos; all are on topographic and/or structural highs of middle Cretaceous reef or reef-associated limestone, which generally is overlain unconformably by strata that range in age from Late Cretaceous to Oligocene.

The various offshore fields are discussed from north to south. The Arrecife Medio field, drilled from August 1963 to November 1966, has 3 producers and 5 dry holes. Approximately 1,450 b/d of oil and 444 Mcf/d of gas are produced from the field. Isla de Lobos field--the first offshore discovery--drilled from May 1963 to July 1964, has eight producers. Approximately 7,300 b/d of oil and 1,200 Mcf/d of gas are produced. Tiburon field has been drilled since July 1964, and has 5 producers, 2 dry holes, and 1 well abandoned because of mechanical difficulties. Approximately 2,635 b/d of oil and about 470 Mcf/d of gas are produced. Atun field was discovered in 1967 and is being developed. Of the completed wells, 2 produce only gas, 2 produce oil and gas, and 1 was plugged because it reached he reef below the oil-water contact. This field presently can produce 6,856 b/d of oil and approximately 5,100 Mcf/d of gas.

The following wells are considered as discoveries of fields similar to some of those described. Esturion No. 1 produces 623 b/d of oil and 188 Mcf/d of gas; Bagre No. 1-A produces 950 b/d of oil and 614 Mcf/d of gas; Pez Vela No. 1 found a gas reservoir whose potential was not determined.

The following discoveries were considered noncommercial. Robalo No. 1 produced approximately 180 b/d of oil and 46 Mcf/d of gas; and Tintorera No. 1 produced approximately 55 b/d of oil and an insignificant amount of gas. Three wells found salt water, probably because of a low structural and/or paleotopographical position. These are Pulpo Nos. 1-A and 2 and Pargo 1.

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