Mineralogical, chemical and isotopic perturbations induced in shale by fluid circulation in a fault at the Tournemire experimental site (Aveyron, France)

Peyaud, Jean-Baptiste; Pagel, Maurice; Cabrera, Justo; Pitsch, H.

doi:10.1016/j.gexplo.2005.09.001

Cited by 12 publications

(15 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The internal architecture and the geometry of the fault zones were determined by small-scale mapping of the galleries' walls and floor and through the geological and geophysical logging of .25 boreholes (Figure 1). F1 and F2 have a similar dip and dip-direction varying spatially between N1708-to-N0108 and 608-to-808W (Lefevre et al, 2015) and are characterized by reverse left-lateral strike slip movement (Peyaud et al, 2006). The F1 fault zone exhibits a complex array of anastomosed fault surfaces consisting of brittle fractures and ductile shear bands, whereas F2 presents two main architectural elements: a central fault core which accommodates most of the displacement and a surrounding fault damage zone.…”

Section: Methodsmentioning

confidence: 99%

The internal architecture and permeability structures of faults in shale formations

Dick¹,

Wittebroodt²,

Courbet³

et al. 2016

Filling the Gaps - From Microscopic Pore Structures to Transport Properties In Shales

View full text Add to dashboard Cite

The evaluation of fluid flow through fractures and faults is of primary importance for the long-term performance assessment of radioactive waste repositories in shale formations and could be used to assess CO 2 storage security or the integrity of caprocks and reservoir capacity. This study focuses on the structural evolution within brittle to ductile shear zone in order to understand permeability enhancement and sealing processes affecting a strike-slip fault system within the Toarcian shale formation from the Tournemire Underground Research Laboratory (URL), southern France. A combination of quantitative field measurements and laboratory and in situ experiments was used to estimate the fluid-flow properties of a fractured shale formation. Results indicate that microfractures govern the matrix porosity in the damage zone and play an increasingly dominant role in fluid flow along the boundary between fault core and fault damage zone.

show abstract

Section: Methodsmentioning

confidence: 99%

The internal architecture and permeability structures of faults in shale formations

Dick¹,

Wittebroodt²,

Courbet³

et al. 2016

Filling the Gaps - From Microscopic Pore Structures to Transport Properties In Shales

View full text Add to dashboard Cite

show abstract

“…Our analysis is showing that the size of the pyrite grain is typically in the range 0.1-1 mm. Peyaud et al (2006) mentioned that the filling of most of the large-scale fractures consists of calcite veins with the presence of pyrite and sometimes barite. Because of the lack of prior knowledge about the amount of pyrite in the material filling these fractures, we performed also a mineralogical analysis of the filling material using the X-ray diffraction method.…”

Section: Detection Of the Calcite-filled Fracturesmentioning

confidence: 99%

Localization and characterization of cracks in clay‐rocks using frequency and time‐domain induced polarization

Okay

Cosenza

Ghorbani

et al. 2012

Geophysical Prospecting

View full text Add to dashboard Cite

International audienceInduced polarization (IP) is a geophysical method that is potentially sensitive to the presence of cracks in porous rocks and therefore to damage. We performed time-domain and frequency domain IP measurements at the Tournemire Underground Research Laboratory (URL, Aveyron, France) in areas where different types of cracks are observed. These cracks correspond to both tectonic fractures and new cracks associated with stress release and desiccation resulting from the excavation of a gallery. These measurements were performed both in eastern and northern galleries of the test site. The eastern gallery was excavated in 1996 while the northern gallery was excavated recently in 2008. This gives us the opportunity to study the electrical characteristics of the excavation damaged zone surrounding the galleries with respect to the age of the excavation. Longitudinal profiles were performed along the floor of the galleries with 48 Cu/CuSO4 electrodes separated by a distance of 20 cm. Chargeability and resistivity were inverted using a Gauss-Newton iterative approach assuming an isotropic heterogeneous clay-rock material. The resulting IP tomograms show a correlation between high values of chargeability and the presence of calcite-filled tectonic fractures. X-ray analysis indicates that the presence of pyrite in these fractures is a potential source of the observed IP signals. The cracks associated with the mechanical damage of the formation exhibit low values of chargeability, on the same order of magnitude than the chargeability of the clay-rock matrix and are therefore hardly observable. A smaller IP response associated with the presence of these cracks is observed in the older gallery and this observation is qualitatively related to the desaturation process associated with these cracks. In a specific area of one of the galleries, the presence of calcareous nodules is observed to be an important source of anomalous chargeability. This signature seems to be associated with the presence of pyrite

show abstract

“…If this is the case, then the rock-buffered fluid system was replaced by the fluid-buffered one close to the fault zones (cf. Peyaud et al, 2006). All syntectonic fluid systems are not necessarily rock buffered by an immediate host rock.…”

Section: Constrained Fluid Flowmentioning

confidence: 99%

Litho-stratigraphic effect on Variscan fluid flow within the Prague synform, Barrandian: Evidence based on C, O, Sr isotopes and fluid inclusions

Slobodník

Melichar

Hurai

et al. 2012

Marine and Petroleum Geology

View full text Add to dashboard Cite

Mineralogical, chemical and isotopic perturbations induced in shale by fluid circulation in a fault at the Tournemire experimental site (Aveyron, France)

Cited by 12 publications

References 17 publications

The internal architecture and permeability structures of faults in shale formations

The internal architecture and permeability structures of faults in shale formations

Localization and characterization of cracks in clay‐rocks using frequency and time‐domain induced polarization

Litho-stratigraphic effect on Variscan fluid flow within the Prague synform, Barrandian: Evidence based on C, O, Sr isotopes and fluid inclusions

Contact Info

Product

Resources

About