--> Abstract: Early Petroleum Exploration, Rocky Mountain Region, U.S.A., by R. J. Weimer; #91004 (1991)

Datapages, Inc.Print this page

Early Petroleum Exploration, Rocky Mountain Region, U.S.A.

WEIMER, ROBERT J., Consultant, Golden, CO

Historically, geology exposed on the flanks of Rocky Mountain uplifts has given unique opportunities to integrate surface and subsurface data to understand the petroleum geology of the intermontane basins. Exploration evolved from drilling near seeps to mapping of surface anticlines, to use of geophysics and subsurface data acquired by drilling. Since 1951 exploration has utilized all methods in the search for closed anticlines and subtle traps related to stratigraphic changes,

unconformities, faults or fractures, and hydrodynamic and diagenetic changes.

Oil seeps were first recorded by explorers in Wyoming in 1832 (Dallas dome, Wind River basin) and 1847 (Absaroka thrust, southwest area). Oil skimmed from springs was used for medicinal purposes and sold for wagon lubrication. The first commercial well was drilled in 1862 by an oil seep 9 mi north of Florence, Colorado. Subsequent drilling led to the discovery of the Florence field which has now produced more than 15,000,000 barrels of oil. Production is from fractured Cretaceous shale in a tilted graben with a fault trap on the updip side.

Early fields were geologically diverse and reports describing the accumulations developed concepts that guided exploration in the region. The following fields illustrate the wide range of trapping conditions.* Faults and Fractures on Homoclinal Dip:* Florence-Oil Creek area (1862) and Boulder (1901), Colorado; mining of gilsonite veins (1889), Uinta basin, Utah* Closed Anticline: Dallas dome (1884) and Salt Creek (1908), Wyoming; Rangely (1902), Colorado* Stratigraphic Change on Anticlinal Plunge or Regional Dip: Moorcroft (1888) and Shannon (1889), Wyoming* Syncline: Mexican Hat (1907), Utah; Blanco gas field (1926), New Mexico* Unconformity: Kevin-Sunburst (1922), Montana Techniques and ideas developed in areas peripheral to the Rocky Mountains also influence exploration in the over ll region, especially Kansas, Oklahoma, and Canada.

 

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)