Capillary sealing in sedimentary basins; a clear field example

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doi: 10.1029/97GL03775
Author(s): Revil, A.; Cathless, L. M., III; Shosa, J. D.; Pezard, P. A.; de Larouzière, F. D.
Author Affiliation(s): Primary:
Cornell University, Ithaca, NY, United States
CEREGE, France
Laboratoire de Mesures en Forage, France
Volume Title: Geophysical Research Letters
Source: Geophysical Research Letters, 25(3), p.389-392. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0094-8276 CODEN: GPRLAJ
Note: In English. 16 refs.; illus.
Summary: Pore fluid overpressures as high as 2 MPa (full lithostatic) are observed at ODP Site 975 starting at depths of 145 mbsf (meters below the sea floor). Sediment porosity increases to near surface values below the top of overpressure, while compaction and pressures above the seal are normal. Spikes in the density log and degassing of core from the overpressured zone indicate the presence of gas. The high porosity sediments are far too permeable to allow the generation and maintainance of fluid overpressures by disequilibrium compaction alone. The presence of two fluid phases in a layered sequence of fine and coarse sediment suggests capillary sealing, and this is shown to be quantitatively feasible. Copyright 1998 by the American Geophysical Union.
Year of Publication: 1998
Research Program: ODP Ocean Drilling Program
Key Words: 07 Marine Geology and Oceanography; Basins; Capillarity; Fluid phase; Leg 161; Marine sediments; ODP Site 975; Ocean Drilling Program; Overpressure; Pore water; Porosity; Sealing; Sedimentary basins; Sediments
Coordinates: N385348 N385348 E0043036 E0043036
Record ID: 1998062742
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