About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 69 (1985)

Issue: 5. (May)

First Page: 851

Last Page: 851

Title: Regional Trends in Previous HitPorosityNext Hit and Permeability of J Previous HitSandstoneNext Hit in Denver Basin--Controls of Burial History: ABSTRACT

Author(s): D. K. Higley, D. L. Gautier

Article Type: Meeting abstract


The Lower Cretaceous J Previous HitsandstoneNext Hit is the principal Previous HitreservoirNext Hit for oil and gas in the Denver basin of Colorado, Wyoming, and Nebraska. Net pay of the J Previous HitsandstoneNext Hit depends strongly on Previous HitsandstoneNext Hit depositional environments, but other important aspects of Previous HitreservoirNext Hit quality reflect the burial history. Most notable of these are Previous HitporosityNext Hit, permeability, depth, and degree of thermal maturation (as indicated by vitrinite reflectance). An understanding of the regional interrelationships between these variables is important in Previous HitpredictingNext Hit Previous HitreservoirNext Hit quality and in estimating undiscovered petroleum resources in the Denver basin.

Statistical treatment of the core analysis and well-log data from 134 widespread boreholes across the basin, for which the U.S. Geological Survey has core, reveal the following. (1) Thermal maturity increases exponentially with depth, indicating increased temperature with burial. (2) Previous HitPorosityNext Hit decreases linearly with increasing Ro and depth. The presence of authigenic clays and carbonate cements are important to Previous HitporosityNext Hit reduction. In many examples across the basin, however, quartz pressure solution and precipitation processes are the main causes of Previous HitporosityNext Hit reduction, and these phenomena may be temperature-limited. (3) Permeability decreases exponentially with increasing depth. The permeability data exhibit more scatter than Previous HitporosityNext Hit, indicating a less direct relationship t depth and reflecting the effects of both Previous HitporosityNext Hit loss and increased surface area of the pore network. Authigenic clays, especially ordered illite-smectite, control the specific surface area of the pore network in the J Previous HitsandstoneTop.

End_of_Article - Last_Page 851------------

Copyright 1997 American Association of Petroleum Geologists