Nanoscale porosity in SAFOD core samples (San Andreas Fault)

Janssen, C.; Wirth, Richard; Reinicke, Andreas; Rybacki, E.; Naumann, Rudolf; Wenk, Hans‐Rudolf; Dresen, Georg

doi:10.1016/j.epsl.2010.10.040

Cited by 56 publications

(30 citation statements)

References 39 publications

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“…Rymer, 2007, 2012;Schleicher et al, 2010;Holdsworth et al, 2011;Bradbury et al, 2011;Lockner et al, 2011). Janssen et al (2011) suggest that the presence of abundant clay minerals is often related to the occurrence of nanoscale porosity that may indicates high fluid pressure.…”

Section: Fault Rock Compositionmentioning

confidence: 99%

“…Richard et al (2013) described foliated domains with preferred orientation, formed by pressure-solution creep mechanisms in the damaged zone and foliation without preferential orientation in the CDZ. Janssen et al (2011) supposed that porosity was enhanced by dissolution and precipitation reactions and the formation of alteration products (clay minerals). For TCDP samples, evidence for dissolutioneprecipitation processes (e.g.…”

Section: Dissolutioneprecipitation Processesmentioning

confidence: 99%

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Faulting processes in active faults – Evidences from TCDP and SAFOD drill core samples

Janssen

Wirth

Wenk

et al. 2014

Journal of Structural Geology

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a b s t r a c tThe microstructures, mineralogy and chemistry of representative samples collected from the cores of the San Andreas Fault drill hole (SAFOD) and the Taiwan Chelungpu-Fault Drilling project (TCDP) have been studied using optical microscopy, TEM, SEM, XRD and XRF analyses. SAFOD samples provide a transect across undeformed host rock, the fault damage zone and currently active deforming zones of the San Andreas Fault. TCDP samples are retrieved from the principal slip zone (PSZ) and from the surrounding damage zone of the Chelungpu Fault. Substantial differences exist in the clay mineralogy of SAFOD and TCDP fault gouge samples. Amorphous material has been observed in SAFOD as well as TCDP samples. In line with previous publications, we propose that melt, observed in TCDP black gouge samples, was produced by seismic slip (melt origin) whereas amorphous material in SAFOD samples was formed by comminution of grains (crush origin) rather than by melting. Dauphiné twins in quartz grains of SAFOD and TCDP samples may indicate high seismic stress. The differences in the crystallographic preferred orientation of calcite between SAFOD and TCDP samples are significant. Microstructures resulting from dissolutioneprecipitation processes were observed in both faults but are more frequently found in SAFOD samples than in TCDP fault rocks. As already described for many other fault zones clay-gouge fabrics are quite weak in SAFOD and TCDP samples. Clay-clast aggregates (CCAs), proposed to indicate frictional heating and thermal pressurization, occur in material taken from the PSZ of the Chelungpu Fault, as well as within and outside of the SAFOD deforming zones, indicating that these microstructures were formed over a wide range of slip rates.

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Section: Fault Rock Compositionmentioning

confidence: 99%

Section: Dissolutioneprecipitation Processesmentioning

confidence: 99%

Faulting processes in active faults – Evidences from TCDP and SAFOD drill core samples

Janssen

Wirth

Wenk

et al. 2014

Journal of Structural Geology

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“…Thus, fault core features are of utmost importance in controlling the migration of microorganisms through tectonic discontinuities behaving as aquitards, as significant cell removal is possible due to mechanical filtration and/or adsorption to clay particles (e.g., Harvey & Garabedian, 1991;Becker et al, 2003;Jiang et al, 2007;Naclerio et al, 2009). For example, Janssen et al (2011) studied porosity in core samples taken within the San Andreas Fault (California) and found the largest pores had an equivalent radius slightly greater than 200 nm, which is significantly smaller than bacterial cell size (typically up to a few microns). However, no works have analyzed the migration of microorganisms through low-permeability fault zones at field scale.…”

Section: Introductionmentioning

confidence: 99%

Bacterial migration through low-permeability fault zones in compartmentalised aquifer systems: a case study in Southern Italy

Bucci¹,

Petrella²,

Naclerio³

et al. 2014

IJS

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“…For the average porosity, the values for the MEDIUM scenario (see Annex, table 1) with a fault porosity of 18% are applied. 18% is the maximum value found in a core from the San Andreas Fault (Janssen et al 2011).…”

Section: Realistic Faults Modelmentioning

confidence: 87%

Simulating seismic chimney structures as potential vertical migration pathways for CO2 in the Snøhvit area, SW Barents Sea: model challenges and outcomes

et al. 2016

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Carbon Capture and Storage (CCS) activities at the Snøhvit field, Barents Sea, will involve carrying out an analysis to determine which parameters affect the migration process of CO2 from the gas reservoir, to what degree they do so and how sensitive these parameters are to any changes. This analysis will aim to evaluate the effects of applying a broad but realistic range of reservoir, fault and gas chimney properties on potential CO2 leakage at various depths throughout the subsurface. Fluid flow might take place through parts of or the entire extent of the overburden. One of the aims of the analysis is assessing the potential of CO2 reaching the seabed. Using the Snøhvit gas reservoir and overburden in the Barents Sea, a series of geological models were built using seismic and well-log data. We then performed numerical simulations of CO2 migration in focused fluid flow structures. Identification of potential migration pathways and their extent, such as gas chimneys and faults, and their incorporation into these models and simulations will provide a realistic insight into the migration potential of CO2. In the simulations the CO2 is injected over a 20 year period at a rate of 0.7 Mt/year and migration is allowed to take place over a 2000 year time frame for domains of approximately 21 Km 2 for the caprock fault models, 24 Km 2 for the realistic gas chimney models and 35 Km 2 for the generic gas chimney models, in a layered sedimentary succession. The total mass of CO2 injected in the reservoir during the 20-year injection period is 14 Mt. There is a strong interaction between the various parameters but the parameter that had the most influence on the CO2 migration process was probably the permeability of the reservoirs, especially the average permeability (k). Also, for the faulted caprock scenarios, it should be noted that at near surface depths the permeability of 765 mD is already adequate for a good CO2 flow. At the chimney top level (600 m) however, a further increase in permeability has an additional effect on improving CO2 flow. Overall, considering the slow upward migration velocity of the plume, this geological setup can be regarded as a suitable storage site.

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Nanoscale porosity in SAFOD core samples (San Andreas Fault)

Cited by 56 publications

References 39 publications

Faulting processes in active faults – Evidences from TCDP and SAFOD drill core samples

Faulting processes in active faults – Evidences from TCDP and SAFOD drill core samples

Bacterial migration through low-permeability fault zones in compartmentalised aquifer systems: a case study in Southern Italy

Simulating seismic chimney structures as potential vertical migration pathways for CO2 in the Snøhvit area, SW Barents Sea: model challenges and outcomes

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