000			01947nab a2200205 4500
005			20260520001830.0
008			260224s2010 xxu
100	1		_aBriqueu, L. _945612
100	1		_aZaourar, N. _945613
100	1		_aLauer-Leredde, C. _945614
245	0	0	_aWavelet based multiscale analysis of geophysical downhole measurements: Application to a clayey siliclastic sequence
260			_cabr. 2010
270			_a13/07/2010 ; 13/07/2010
300			_a9 p. ; 112-120
520			_aTranscripción del resumen del autor. In order to reveal the structural properties at small scale within a geological unit apparently homogeneous at large scale, we explore the stochastic components of petrophysical measurements recorded in a borehole drilled through the Cretaceous siliclastic units of the South-eastern Basin of France. First, we analyse the instantaneous fluctuations of gamma ray log measurements searching for scaling laws in its power spectrum. Power spectra indicate a scaling behaviour with average exponent ßa values mostly falling in the range 1 < ßa < 3, a typical fingerprint of fractional Brownian motion. We show that the changes in scaling exponents extracted from the natural gamma ray measurement by a Continuous Wavelet Transform present a close correlation with the stochastic behaviour of radioactive decay processes described by the Poisson's law. Secondly, we investigate the stochastic component of three different electrical resistivity logs. In the space/frequency domain explored by a Continuous Wavelet Transform, their local spectral densities show self-affine proprieties. An integrated statistical analysis of the local variations of the three pseudo-logs extracted from these measurements allows to point out new petrophysical heterogeneity within the silty unit.
581			_a3-4
773	0		_tJournal of Petroleum Science & Engineering _g71
942			_cARTICULO
999			_c174944 _d174944