Print Email Facebook Twitter Experimental validation of fracture aperture determination from borehole electric microresistivtiy measurements Title Experimental validation of fracture aperture determination from borehole electric microresistivtiy measurements Author Ponziani, M. Slob, E.C. Luthi, S.M. Bloemenkamp, R. Le Nir, I. Faculty Civil Engineering and Geosciences Department Geoscience & Engineering Date 2015-05-01 Abstract We studied the electric response of fractures with laboratory experiments and numerical simulations for a full-bore formation microimaging tool. The laboratory setup was designed and built to perform controlled experiments with accurate measurements of all principal properties involved for electric borehole imaging. These properties are formation resistivity, mud resistivity, fracture aperture, pad position, and button current. The experiments were conducted on two types of limestone for fracture apertures ranging from 0.1 to 0.9 mm and mud/formation resistivity contrasts varying from 1/100 to 1/10,000. A numerical model was used to reproduce the laboratory configuration and to validate the results. The model proved to be an effective tool to optimize the experimental setup, and it was also used to study the effect of standoff (up to 5 mm) on the measured integrated additional current. Linear relationships between the fracture aperture and measured integrated current were found to be valid for the laboratory experiment and the corresponding numerical simulation. The measured integrated current could therefore be used to determine the fracture aperture if the other parameters are known. Two coefficients in the relationship were found to differ from those previously found using numerical simulations for the actual borehole situation. These differences are attributed to tool- and scale-dependent factors. Subject borehole geophysicsfracturesimagingresistivity log To reference this document use: http://resolver.tudelft.nl/uuid:4189344d-ec3f-4b5d-8a46-f823342af294 Publisher Society of Exploration Geophysicists ISSN 0016-8033 Source https://doi.org/10.1190/geo2014-0334.1 Source Geophysics, 80 (3), 2015 Part of collection Institutional Repository Document type journal article Rights © 2015 Society of Exploration Geophysicists Files PDF 318115.pdf 1.22 MB Close viewer /islandora/object/uuid:4189344d-ec3f-4b5d-8a46-f823342af294/datastream/OBJ/view