Compaction and porosity evolution of Pliocene sandstones, Ventura basin, California

Journal Article · Wed Jun 01 04:00:00 EDT 1988 · AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States)

OSTI ID:6023686

Wilson, J C; McBride, E F

Sandstones of the Pico and Repetto formations were studied to quantify the processes involved in compaction and to determine the porosity evolution of the beds during burial. The sandstones are mineralogically immature and, except for local carbonate-cemented beds, have insufficient cement to have prevented compaction. Stratigraphic studies and graphic porosity-depth plots suggest that the samples maximum burial depths were approximately 10,000 ft (3048 m) deeper than the present-day depths of 850-13,000 ft (259-3962 m). Assuming sands had 40% initial porosity, the sandstones that are at present most deeply buried lost a total absolute porosity of 26% by all compactional processes, which includes 14% by grain rearrangement and 6% each by pressure solution and ductile grain deformation. Secondary porosity averages 20-40% of the total thin-section porosity. Secondary porosity is present at all depths, but makes up the greatest percentage of total porosity between present depths of 6000 and 9500 ft (1829 and 2896 m). Except for grain fracturing, secondary porosity formed only by dissolution of framework grains. Fractured-grain porosity contributes up to 29% of total porosity (5% absolute porosity) in some samples; fractures formed during Pleistocene tectonic episodes. 11 figures, 6 tables.

• Research Organization: Univ. of Texas, Austin (USA)
• OSTI ID: 6023686
• Journal Information: AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States), Journal Name: AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States) Vol. 72:6; ISSN AABUD
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
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& Exploration
CALIFORNIA
CENOZOIC ERA
FEDERAL REGION IX
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGY
MINERAL RESOURCES
NORTH AMERICA
PERMEABILITY
PETROLEUM DEPOSITS
PLIOCENE EPOCH
POROSITY
RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY ROCKS
SOURCE ROCKS
STRATIGRAPHY
TECTONICS
TERTIARY PERIOD
USA