Porosity corrections for smectite-rich sediments: Impact on studies of compaction, fluid generation, and tectonic history

Brown, Kevin M.; Ransom, Barbara

doi:10.1130/0091-7613(1996)024<0843:pcfsrs>2.3.co;2

Cited by 82 publications

(83 citation statements)

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“…The investigated saponites were prepared at ISTO (Orléans, France) by hydrothermal treatment as described in detail elsewhere, 40 before being sodium saturated. 20 Their structural formulas are the following: Na x (Si 8-x ,Al x )(Mg 6 )O 20 (OH) 4 , with x ) 0.8 and 1.4. The two samples are hereafter referred to as S-Na 0.8 and S-Na 1.4 , respectively.…”

Section: Methodsmentioning

confidence: 99%

Hydration Properties and Interlayer Organization of Water and Ions in Synthetic Na-Smectite with Tetrahedral Layer Charge. Part 1. Results from X-ray Diffraction Profile Modeling

Ferrage¹,

Lanson²,

Michot³

et al. 2010

J. Phys. Chem. C

210

246

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The dehydration of two Na-saturated synthetic saponites with contrasting layer charge was studied by modeling the X-ray diffraction (XRD) patterns recorded along a water vapor desorption isotherm. The interlayer configurations used to reproduce the XRD data over a large angular range include Na + cations located in the interlayer midplane and H 2 O molecules normally distributed about one or two main positions for mono-and bihydrated layers, respectively. Although strongly reduced in comparison to natural smectites, hydration heterogeneity was systematically observed for these synthetic saponites, especially along the transition between two hydration states. Using improved models for the description of the interlayer organization, the influence of layer charge on the structure of interlayer water can be precisely assessed. In addition, the comparison with water contents obtained from water vapor gravimetry experiments allows discriminating the relative contributions of H 2 O molecules from 1W and 2W interlayers (crystalline water) and from the pore space network.

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Section: Methodsmentioning

confidence: 99%

Hydration Properties and Interlayer Organization of Water and Ions in Synthetic Na-Smectite with Tetrahedral Layer Charge. Part 1. Results from X-ray Diffraction Profile Modeling

Ferrage¹,

Lanson²,

Michot³

et al. 2010

J. Phys. Chem. C

210

246

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“…For a given porosity value, Leg 156 permeabilities are somewhat lower than Leg 110 permeabilities. Brown and Ransom (1996) suggest that porosity values in the Barbados accre- Figure 5. Plot of porosity vs. permeability (after Bekins, 1995), based on data for argillaceous formations compiled by Neuzil (1994;shaded region), Leg 110 permeability measurements are from Taylor and Leonard (1990;black circles), and porosity-permeability functions are from Bekins, et al (1995;dashed and solid lines).…”

Section: Porosity Vs Permeabilitymentioning

confidence: 99%

Evaluation of hydrogeologic properties of the Barbados accretionary prism: a synthesis of Leg 156 results

Zwart¹,

Brückmann²,

Moran³

et al. 1997

Proceedings of the Ocean Drilling Program, 156 Scientific Results

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In situ and laboratory studies of permeability, conducted by Ocean Drilling Program scientists from Leg 156, provide constraints on parameters controlling the hydrogeologic system in the Barbados accretionary prism. Results from these studies indicate that core-scale and formation-scale permeability values differ by at least several orders of magnitude and are dependent on pore-fluid pressure and effective stress conditions. Direct measurement from packer experiments and indirect evidence from consolidation tests suggest that pore-fluid pressures are commonly above hydrostatic values and approach lithostatic values within the décollement zone. Permeability and fluid pressure conditions in the Barbados accretionary prism reflect the complexity of the hydrogeologic system of such an active tectonic environment.

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“…The mass balance described by equation (8) involves the total porosity [Brown and Ransom, 1996], as does the calculation of core and cuttings sample porosity values from moisture and density data, which generally agree with the lithodensity log values. In Units IIIb and IV, the difference between the effective porosity (e.g., derived from the sonic log or electric resistivity log) and total porosity (e.g., derived from the lithodensity log) reflects differences in hydrous clay mineral abundance.…”

Section: Discussionmentioning

confidence: 69%

Quantification of free gas in the Kumano fore-arc basin detected from borehole physical properties: IODP NanTroSEIZE drilling Site C0009

Doan

Conin

Henry

et al. 2011

Geochem. Geophys. Geosyst.

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[1] The Kumano fore-arc basin overlies the Nankai accretionary prism, formed by the subduction of the Philippine Sea Plate beneath the Eurasian plate offshore the Kii Peninsula, SW Honshu, Japan. Seismic surveys and boreholes within the framework of the Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) project show evidence of gas hydrates and free gas within the basin. Here we use high-quality borehole sonic data from Integrated Oceanic Drilling Program (IODP) Site C0009 to quantify the free gas distribution in the landward part of the basin. The Brie theory is used to quantify gas content from sonic logs, which are calibrated from laboratory measurements on drill cores. First, we show that the sonic data are Copyright 2011 by the American Geophysical Union 1 of 12 mainly sensitive to the fluid phase filling the intergranular pores (effective porosity), rather than to the total porosity that includes water bound to clay minerals. We then compare the effective porosity to lithodensityderived porosity that acts as a proxy for total porosity. The combination of these two data sets also allows assessment of clay mineralogy of the sediments. Second, we compute free gas saturation and find a gasrich interval that is restricted to a lithological unit characterized by a high abundance of wood fragments and lignite. This unit, at the base of the fore-arc basin, is a hydrocarbon source that should be taken into account in models explaining gas distribution and the formation of the bottom-simulating reflector within the Kumano fore-arc basin.

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Porosity corrections for smectite-rich sediments: Impact on studies of compaction, fluid generation, and tectonic history

Cited by 82 publications

References 0 publications

Hydration Properties and Interlayer Organization of Water and Ions in Synthetic Na-Smectite with Tetrahedral Layer Charge. Part 1. Results from X-ray Diffraction Profile Modeling

Hydration Properties and Interlayer Organization of Water and Ions in Synthetic Na-Smectite with Tetrahedral Layer Charge. Part 1. Results from X-ray Diffraction Profile Modeling

Evaluation of hydrogeologic properties of the Barbados accretionary prism: a synthesis of Leg 156 results

Quantification of free gas in the Kumano fore-arc basin detected from borehole physical properties: IODP NanTroSEIZE drilling Site C0009

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