000 02368nab a2200193 4500
005 20260520000224.0
008 260224s2009 xxu
245 0 0 _aFracture characterization at multiple scales using borehole images, sonic logs, and walkaround vertical seismic profile
260 _a
_b
_cnov. 2009
270 _a17/06/2010 ; 17/06/2010
300 _a14 p. ; 1503-1516
520 _aTranscripción del resumen del autor. We present a quantitative forward-modeling methodology to link and interpret several measurements relevant to mechanical properties of fractures such as borehole images, sonic anisotropy logs, and borehole seismic anisotropy. The analysis is applied to a case study from a north African tight gas field using data from a vertical well. Two studies are conducted independently using the same geological fracture data to model fracture-induced anisotropy. In the first study, we use the orientation of the natural and drilling-induced fractures interpreted on the image log to model the azimuthal fracture-induced anisotropy at the sonic scale. The mechanical effects of natural and drilling-induced fractures are treated using different compliance parameters for each fracture type. We show that modeled sonic fast shear azimuths could be biased by the presence of noncompliant fractures in each fracture type, and we propose an empirical selection criterion to reject noncompliant fractures prior to compliance estimation. Then, we estimate the fracture compliances and confirm that natural open fractures have larger compliances than drilling-induced fractures. In the second study, we apply interpreted borehole images toward modeling of the azimuthal vertical seismic profile (VSP) attributes as a function of source azimuthal position. Natural fractures inside a window of height, h, and located at depth, d, are included, and several volume sizes and positions (i.e., h and d) are considered. We find a good agreement between modeled and observed transverse-over-radial displacement trends using natural fractures within windows located at the depth of the VSP receiver, and having window heights on the order of one to two VSP shear wavelengths.
581 _a11
773 0 _tAAPG Bulletin
_g93
942 _cARTICULO
100 1 _aPrioul, Romain
_942963
100 1 _aJocker, Jeroen
_942964
999 _c171179
_d171179