FUTURE PETROLIFEROUS PROVINCES OF VENEZUELA

摘要

Recent regional studies have indicated that a resource potential greater than 40 billion barrels oil equivalent remains to be found in Venezuela. Evidence for new petroliferous provinces that hold this potential are discussed in this paper. Venezuela is a showcase for the exceptional foredeep basins of northern South America, along with outstanding oil-source rocks and reservoirs associated with unconformities within these foredeeps. In the southwest of the country, sandstones above and below the foredeep unconformity form potential stratigraphic traps, a possible western extension of the prolific Eastern Venezuelan Basin. This would be an exceptional area to evaluate weathered/fractured basement plus Jurassic fills of half grabens located below the passive-margin sequence. Also in the west, the northern and southern flanks of the Merida Andes, with 70 oil seeps, remain virtually unexplored. Other areas with significant petroleum potential are the 7600m (25,000 ft) of mostly Neogene sediments offshore the Orinoco Delta, where five wells have tested 5 trillion cubic feet of gas plus condensate; a diapir wall 160 km (100 miles) in the middle of the Eastern Venezuelan Basin with three major fields; and the 110-km-long (70-mile-long) downthrown Anaco inverted structure, tested in two localities. The mountain fronts to the north are being drilled to evaluate the northern extension of the giant Furrial trend and a new thrust play to the northwest. The 150,000-km~2 (60,000-mile~2) offshore area has only 50 wildcats, most drilled as tests for conventional traps. However, complex strike-slip structures, stratigraphic traps, and deep-water plays could exist. Oil seeps and shows in wells indicate that this is an oil-prone area.