Éditeur(s) : HAL CCSD Cambridge University Press (CUP)
Résumé : International audience
XFILM is a computer program for determining the thickness and composition of thin films on Substrates and multilayers by electron probe microanalysis. In this study, we describe the X-ray emission model implemented in the latest version of XFILM and assess its reliability by comparing measured and calculated k-ratios from thin-film samples available in the literature. We present and discuss examples of applications of XFILM that illustrate the capabilities of the program.
ISSN: 1431-9276

hal-00475542
https://hal.archives-ouvertes.fr/hal-00475542
DOI : 10.1017/S1431927609991218

Éditeur(s) : HAL CCSD American Association of Petroleum Geologists
Résumé : International audience
Determination of the membrane seal capacity of deformation bands is critical for managing geologic reservoirs in porous sandstones. In this study, we have analyzed a cataclastic shear-band network developed in uncemented porous sandstone in Provence, France. Geometrical analyses of the bands show significant differences between three types of bands (single strand, multistrand, and band cluster), sorted by their number of strands, their amount of shear displacement, and their thicknesses. At the microscopic scale, the image-analysis porosities and the grain-size distributions allow definition of three different types of microstructural deformation: damage zone, protocataclastic, and cataclastic. Whereas damage zone and protocataclastic deformations are observed in each type of band, cataclastic strands are observed in clusters and, sometimes, in multistrands. Cataclastic strands are characterized by a porosity reduction of 10 to 25% and a permeability reduction of three to five orders of magnitude compared to the host rock. Field observations of iron hydroxide precipitations around the bands suggest that cataclastic strands were membrane seals to water flow under vadose condition. This study therefore highlights the importance of the degree of cataclasis in shear bands as membrane seals to subsurface fluid flows in sandstone reservoirs.
ISSN: 0149-1423

hal-00766557
https://hal.archives-ouvertes.fr/hal-00766557
DOI : 10.1306/04051211097