The Rio Zulia field in northeastern Colombia lies within the southernmost part of the oil-rich Maracaibo basin. The field measures 3.4 by 0.9 mi (5.5 by 1.5 km) and is located on a faulted anticline whose southeastern flank is cut by an east-directed thrust fault. Cumulative production during the 20 years since Chevron discovered it in March 1962 is 125 million bbl. The oil is brown, paraffinic, and has a gravity of 41.5° API. Maximum production of 35,000 BOPD was reached in 1966; present production is about 4,000 BOPD.

Almost all the production has come from the Eocene Mirador Formation, a loosely consolidated fine to coarse-grained, non-calcareous sandstone with irregularly distributed clay and siltstone interbeds. The sandstone is part of the Eocene delta built out to the northeast over the Lake Maracaibo region. The Mirador of the Rio Zulia area belongs to the back-delta fluvial system.

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