Datapages, Inc.Print this page

Reservoir Geometry of the Regressive Fox Hills Sandstone:

Control on Aquifer Quality*


Marieke Dechesne1 and Robert G. Raynolds1


Search and Discovery Article #50025 (2005)

Posted November 27, 2005


*Oral Presentation at Rocky Mountain Section AAPG Annual Meeting, Jackson, Wyoming, September 24-26, 2005. Appreciation is expressed to Lyn George, Technical Program Chair, and Don French, for encouraging the authors to submit this presentation.


Click to view presentation in PDF format.


1Denver Museum of Nature & Science, 2001 Colorado Boulevard, Denver, CO 80205, phone 303-370-6047 ([email protected]).


In the Denver Basin the littoral to nearshore Fox Hills Sandstone was deposited during the early phase of the Laramide orogeny as the Cretaceous Interior Seaway retreated to the northeast. This approximately 68 MY regressive sandstone is composed of a series of shingles reflecting episodic seaway retreat. We illustrate the detailed geometry of the sandstone elements that make up the Fox Hills Sandstone. This unit is an important aquifer in the Denver Basin and the distribution of porosity, permeability, and facies tracts is important in predicting the performance of water wells. 

A database of thousands of oil and gas wells and thousands of water wells is available for study. A subset of these wells has been analyzed to create a three-dimensional model using ArcGIS software. Seven shingles are mapped in detail. Our three dimensional model permits the effective and efficient communication of critical reservoir parameters to resource planners. Comparisons are made to other well-studied regressive systems in the San Juan and Greater Green River basins. We propose that non-uniform subsidence has influenced the stacking pattern of this regressive succession, controlling both the distribution of net sandstone and of coal-bearing strata. These parameters are critical to predicting reservoir performance and quality. The patterns we document are relevant to any effort to extract fluids from rocks of this facies association.


Denver Basin and location of study area


Source of water supply, Denver Basin area


Fox Hills paleogeography