The History of Oil and Gas Development in the Denver Basin

Abstract

The Denver Basin encompasses an area of about 70,000 square miles in eastern Colorado, southeastern Wyoming, and southwestern Nebraska. More than 1.3 billion barrels of oil, 7.4 trillion cubic feet of natural gas, and 3.6 million barrels of water have been produced from more than 47,000 wells across the basin. Petroleum production is from Mississippian through Upper Cretaceous strata. The first oil well in the basin was completed in 1881 in the Upper Cretaceous Pierre Shale in the Florence field, the oldest active oil field in the United States. Depths of production across the basin vary from less than 900 feet (270 meters) from the Pierre Shale in the Florence field to about 10,000 feet (3,048 meters) in Lower Cretaceous Muddy (J) Sandstone in the Wattenberg field. Focus of conventional production in the basin is the Muddy (J) Sandstone. There is scattered Paleozoic conventional production along the borders of the basin, in Nebraska, Lincoln County in southeast Colorado, and structural traps along the northern boundary of the Wattenberg field. Knowledge of petroleum source rock(s) and resources for Paleozoic strata within the basin are limited by lack of deep drilling; oil and gas in Mississippian and Pennsylvanian units in Lincoln County may have sourced from Paleozoic strata of the Denver Basin, or migrated westward from the Anadarko Basin. Unconventional, primarily horizontal oil and gas wells are concentrated in the Wattenberg field area of the deep basin; production from low-permeability sandstones of the Muddy (J) began in 1970. Exploration and production from tight calcareous shale of the Upper Cretaceous Niobrara Formation was initiated in the early 1900s in the basin, accelerated in the early 1980s, and continues to expand outward from the Wattenberg field, particularly to the northeast. Unconventional sweet spots are concentrated in an area of elevated basement heat flow that enhanced oil and gas generation from bounding organic-rich shales and the Niobrara Formation.

AAPG Datapages/Search and Discovery Article #90216 ©2015 AAPG Annual Convention and Exhibition, Denver, CO., May 31 - June 3, 2015