The Graneros-Greenhorn petroleum system, a possible new resource play, Rocky Mountain region, USA

Abstract

The Graneros-Greenhorn Petroleum System is a widespread unit in the Denver Basin. Organic-rich source rocks are found in both the Graneros and Greenhorn formations (Kaiser, 2012; Durkee, 2016). Reservoir rocks are found in the Greenhorn Limestone. This petroleum system is age equivalent to the Eagle Ford Formation of the Gulf Coast region. Numerous hydrocarbon shows and some vertical well production suggest the high potential for this petroleum system in the Denver Basin (Kaiser, 2013; Durkee, 2016). Horizontal drilling and multi-stage hydraulic fracture stimulation may be keys to future production from this interval. The Graneros and Greenhorn were deposited during the Cenomanian and lower Turonian stages of the Cretaceous (~ 92.1 to 97.2 Ma, Kauffman et al., 1993) (Figures 1, 2). Paleoenvironmental reconstruction for Greenhorn time is shown by Figure 2. This paper illustrates the potential of the Greenhorn to become a resource play and some of the similarities between the Greenhorn and the existing resource play of the Niobrara Formation. The term resource play implies widespread production (continuous accumulation) with somewhat predictable, repeatable results.