Yates Oil Field
The Yates Oil Field is a giant oil field in the Permian Basin of west Texas. Primarily in extreme southeastern Pecos County, it also stretches under the Pecos River and partially into Crockett County. Iraan, on the Pecos River and directly adjacent to the field, is the nearest town. The field has produced more than one billion barrels of oil, making it one of the largest in the United States, and in 2009 it remains productive, though at a diminished rate. Since fracturing has exploded in the Permian Basin, the Yates field has seen very heavy activity in the past 3 years. Estimated recoverable reserves are still approximately one billion barrels, which represents approximately 50% of the original oil in place (OOIP).
The productive area of the oil field covers approximately 26,400 acres (107 km2), or over 41 square miles (110 km2), in a roughly circular area in far eastern Pecos County, south, southwest and west of the town of Iraan. Texas State Highway 349 borders the field on the east, and U.S. Highway 190/193 borders the field on the north, passing through it going west on its way to Interstate 10, 14 miles (23 km) from Iraan. A small part of the field extends across the Pecos River into Crockett County, principally southeast of Iraan.
Terrain is hilly on the field itself, with some steep canyon walls and numerous mesas. The region is along the edge of the Edwards Plateau. Elevations range from 2,300 feet (700 m) along the Pecos River to over 2,800 feet (850 m) on the highest mesas. Average annual rainfall is about thirteen inches, and temperatures range from an average overnight low in January of 31 °F (−1 °C) to a July afternoon high of 96 degrees Fahrenheit. Native vegetation, where present – for much of the area is exposed rock – consists of desert shrubs, grasses, and scrubby live oaks. Drainage is primarily to the north and east, into the Pecos River, which flows south into the Rio Grande.
The Yates field is the southernmost of the large oil fields on the eastern rim of the Central Basin Platform in the Texas Permian Basin, the most productive petroleum-producing region in the continental United States. The Permian Basin is a geologic region, about 300 miles (480 km) long and 250 miles (400 km) across, which was downwarped during the Permian period. During this time it filled with water and became a sea, while the subsidence continued. Over tens of millions of years the sea filled with sediments – principally limestones and dolomites in the area of the Yates Field – and then as the sea evaporated, those sedimentary rocks were capped with a large layer of evaporites, such as potash and sea salt. These stratigraphic sequences are among the thickest collections of Permian rocks in the world. In areas where large anticlines formed, oil from deeper-lying source rocks was trapped in permeable rocks such as the limestone and dolomite underneath the impermeable cap of evaporite sediments.
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