Ceuta-Tomoporo field is located in the southeastern part of the Maracaibo basin in western Venezuela. It has an area of 320 km² and is producing light- to medium-grade oil. The structural framework is characterized by a major left-slip fault, and oil accumulations are associated with extensive compressional structural features. There are indications that the deposition of Eocene sediments has been controlled by normal faulting in some areas and that a period of shortening altered the character of some faults during the late Eocene, or even later. The main producing intervals are shallow water marine or fluviodeltaic sands of Miocene or Eocene age, with porosities ranging from 12 to 17% and a potential production rate of up to 3500 BOPD per well from depths of a out 17,000 ft (5180 m). Most of the oils accumulated in the basin have been derived from the organic-rich, highly oil-prone Cretaceous La Luna source rocks. The reservoirs seem to contain mixtures of hydrocarbons that probably are the results of migration from a common drainage area at different times.