Kinky vitrinite reflectance well profiles: Evidence of paleopore pressure in low-permeability, gas-bearing sequences in Rocky Mountain foreland basins

American Association of Petroleum Geologists Bulletin
By: , and 

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Abstract

Vitrinite reflectance (Rm) profiles of wells drilled in abnormally pressured, low-permeability gas-bearing sequences in Rocky Mountain foreland basins are commonly nonlinear with two or more nonparallel segments. These kinky profiles are most likely due to perturbations of the thermal gradient caused by contrasting heat transfer processes associated with the development of abnormally high pressures. We interpret the intersection of the shallow and intermediate Rm segments to mark the approximate original boundary between normal-pressured, water-bearing rocks and underlying overpressured gas- and water-bearing rocks. The intersection of the intermediate and deep Rm segments marks the approximate original boundary between overpressured gas- nd water-bearing rocks and underlying overpressured gas-bearing rocks. However, because overpressuring is a transient condition that eventually evolves into normal pressuring or underpressuring, these intersections may not coincide with the present top of abnormal pressuring. These segmented Rm profiles occur in several Rocky Mountain basins of the United States and Canada.

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Publication type Article
Publication Subtype Journal Article
Title Kinky vitrinite reflectance well profiles: Evidence of paleopore pressure in low-permeability, gas-bearing sequences in Rocky Mountain foreland basins
Series title American Association of Petroleum Geologists Bulletin
DOI 10.1306/44B4A2D0-170A-11D7-8645000102C1865D
Volume 73
Issue 8
Year Published 1989
Language English
Publisher American Association of Petroleum Geologists
Description 12 p.
First page 999
Last page 1010
Country Canada, United States
State Alberta, Colorado, Wyoming
Other Geospatial Alberta Deep basin, Greater Green River basin, Piceance basin
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