Denver basin

Belitz, K. and J. D. Bredehoeft, 1988, Hydrodynamics of Denver basin, explanation of subnormal fluid pressures. American Association of Petroleum Geologists Bulletin 72,1334-1359. 

Clayton, J. L. and P. J. Swetland, 1980, Petroleum generation and migration in Denver basin. American Association of Petroleum Geologists Bulletin 64, 1613— 1633. 

Lee, M.-K. and C. M. Bethke, 1994, Groundwater flow, late cementation, and petroleum accumulation in the Permian Lyons sandstone, Denver basin. American Association of Petroleum Geologists Bulletin 78,217-237. 

Levandowski, D.W., M. E. Kaley, S. R. Silverman and R. G. Smalley, 1973, Cementation in Lyons sandstone and its role in oil accumulation, Denver basin, Colorado. American Association of Petroleum Geologists Bulletin 57, 2217-2244. 

McConaghy, J. A., G. H. Chase, A. J. Boettcher and T. J. Major, 1964, Hydrogeo-logic data of the Denver basin, Colorado. Colorado Groundwater Basic Data Report 15. 

Wyodak-Anderson duplicate analyses USA Rocky Mountain Denver Basin 0.36—4... 

Weaver (unpublished) detrital in Cretaceous shale, Denver Basin, Colo., U.S.A. analyst I. H. Oslund. 

Chapter 5 Material Balance Considerations for the Generation of Secondary Porosity by Organic Acids and Carbonic Acid Derived from Kerogen, Denver Basin, Colorado, USA... 

The purpose of this chapter is to present material balance calculations to evaluate whether there were sufficent acidic solutions available to explain observed amounts of secondary porosity in sandstones overlying the deepest portion of the Denver Basin (Colorado, USA), which has thermally mature... 

The Denver Basin is asymmetric with a gently dipping eastern flank and a sharply upturned western flank (Fig. 1). This basin was selected for study because it is a relatively small basin with hydrocarbon production from predominantly sandstone reservoirs, which have been extensively cored. Also, considerable data are available on the source rocks in this basin. 

Fig. 1. May showing the asymmetric configuration of the Denver Basin and the area of study, Spindle and Wattenberg fields, which overlies the deep portion of the basin...

Oil in the small Lyons Sandstone reservoirs along the northwest margin of the Denver Basin has distinctly different characteristics than oil in the Cretaceous reservoirs. The source for the Lyons oil is unknown. The source for the oil in the Lower and Upper Cretaceous reservoirs has been established as Cretaceous shales and limestones (Clayton and Swetland 1980) by oil-to-rock correlation techniques. The Carlile Shale, Greenhorn Limestone,... 

Fig. 2. Columnar section for the Wattenberg area of the Denver Basin. The primary source rocks are the shales and limestones of the Dakota Group, Benton Group, and Niobrara Formation. The most important hydrocarbon reservoirs are the Dakota J Sandstone and the Hygiene and Terry sandstones of the Middle Pierre Shale. The Lyons Sandstone, Codell Sandstone of the Benton Group, and limestone of the Niobrara Formation also produce hydrocarbons...

Table 1. Source rock data for Wattenberg area, Denver Basin, used in material balance calculations. Kerogen in these source rocks is almost exclusively Type II...

The Cretaceous shales and limestones are also sources for carbon dioxide and organic acids. The richness and volume of the source rocks, as well as the type of kerogen, are determinants of the volume and type of acids. Humic-rich Type-Ill kerogen is more oxygen-rich and therefore capable of generating more carbon dioxide and organic acids (Hunt 1979). Cretaceous source rocks in the Denver Basin, however, contain Type-II kerogen almost exclusively. 

Fig. 3. Compositional ranges for Cretaceous sandstones in the Wattenberg area of the Denver Basin plotted on a modified (Pettijohn et al. 1987) Dott classification triangle...

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