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The Tupungato oil field is situated 50 kilometers south-southwest of the city of Mendoza in west-central Argentina, in an area just east of the foothills of the Andes Mountains where the principal tectonic features are overthrust faults of late Tertiary age. The surface structure, discovered in 1932, is a closed dome with faulted west flank. The discovery well was completed in 1934 at a depth of 250 meters, and a total of 17 shallow wells were drilled to depths averaging 450 meters, most of which produced oil associated with strong flows of salt water from fractures in the upper part of the Tertiary (Pliocene) section. The discovery well of the Victor zone of Upper Triassic age was completed in 1938 at a depth of 1,796 meters. By the end of 1941, 23 wells had been drilled of which 20 were producing an average of 8,800 barrels per day. The major part of the differences between the structure of the various zones which can be identified in well samples is believed by the author to be due to the presence of low-angle thrust faults which cause variations in the thickness of the Tertiary section in different parts of the field, but this can not be definitely proved. There is some indication of the existence of a gentle fold prior to the deposition of the Tertiary.
The oil occurs in fractures and porosity in the upper part of a thick series of volcanic tuffs, but is believed to be produced almost entirely from the fractures. It is of the same type, with a high paraffine content, as that produced from lower stratigraphic levels in the other oil fields of northern Mendoza. A well to test these deeper zones is now being drilled. The Yacimientos Petroliferos Fiscales is the only operator in the field.
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