Resumo

RUEDA, Jenny et al. METHODOLOGY TO DETERMINE DENSITY OF MICROFRACTURE ON ROCKS FROM ANISOTROPICS PARAMETERS: AN APPROXIMATION IN SYNTHETICS CORES. bol.geol. [online]. 2010, vol.32, n.1, pp.79-93. ISSN 0120-0283.

The anisotropy is a property of the rocks which is generated by diverse factors. To understand which are those factors, is required an extensive analysis. To contribute in the analysis mentioned before, this investigation studied the microfractures density planning that the microfractures anisotropy generators in the rocks. To evaluate the impact of the microfractures in the anisotropy, this work develops an experimental laboratory methodology, in which synthetic models of rocks were used. This models were elaborated with simulated microfractures (inclusions), varying their density. The anisotropy was obtained thanks to ultrasound measurements (an ultrasound device measurement was build up), finding how influences the space density of the microfractures in the speeds of the longitudinal waves or compression (P) and shears (S). As of the obtained results was establish a quantitative relationship between the microfractures density and the anisotropy from ultrasonic waves (S) when they spread through a fractured layer of synthetic composition, contributing with laboratory evidence due to the fact that (1) the microfractures role as anisotropy generators; (2) the direct relationship between the anisotropy from wave S and the density of microfractures from 0% to 4.96% and for values bigger than 4.96% the anisotropy will decrease; and (3) the relative variation of the anisotropy of the waves P and waves S.

Palavras-chave : Anisotropy; microfracture density; anisotropic parameters; simulation of microfracture; ultrasound waves.

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