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

Journal Article · Tue Aug 01 00:00:00 EDT 1989 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:5659837

Law, B E; Nuccio, V F; Barker, C E ^[1]

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1. Geological Survey, Denver, CO (USA)

Vitrinite reflectance (R{sub m}) 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 pressure. The authors interpret the intersection of the shallow and intermediate R{sub m} 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 R{sub m} segments marks the approximate original boundary between overpressured gas- and 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 R{sub m} profiles occur in several Rocky Mountain basins of the US and Canada. 9 figs., 2 tabs.

• OSTI ID: 5659837
• Journal Information: AAPG Bulletin (American Association of Petroleum Geologists); (USA), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Vol. 73:8; ISSN AABUD; ISSN 0149-1423
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
030200* -- Natural Gas-- Reserves
Geology
& Exploration
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
GEOTHERMAL GRADIENTS
MACERALS
MATURATION
MINERAL RESOURCES
MOUNTAINS
NATURAL GAS DEPOSITS
OPTICAL PROPERTIES
PERMEABILITY
PHYSICAL PROPERTIES
POROSITY
RESOURCES
ROCKY MOUNTAINS
SEDIMENTARY BASINS
SOURCE ROCKS
TEMPERATURE GRADIENTS
VITRINITE