000 03867nmc a2200253 4500
005 20260520005605.0
008 260224s2001 xxu ing
041 _aInglés
245 0 0 _aLateral Discrimination Of Sand Packets With 3d-Seismic-Derived Acoustic Impedances, La Itala, Golfo San Jorge, Argentina
_bSPE 69484
260 _aDallas, Texas
_bSociety of Petroleum Engineers
_c2001
270 _a12/09/06 ; 17/07/01
520 _aThe depositional environment in the west section of the Golfo San Jorge Basin is characterized by fluvial sand-shale sequences in which the reservoirs rarely have thickness that exceeds 10m, while average thickness is 4m. The acquired seismic has a tuning thickness of 17m, so that the wavelet effect and thin bed interferences make the seismic derived attribute analysis not ideal for lateral and vertical delineation of sandstone complexes. The seismic limitations of only describing interfaces without discriminating lithologies, is overcome inverting 3D seismic traces into pseudo logs of Acoustic Impedances by applying a constraint sparse spike algorithm. Both well data (lithology and compaction) and horizons (structural framework) help to constrain the process, thus the reflectivity series found meets the criteria of minimizing the residual between the synthetic model and the real 3D seismic trace. An Acoustic Impedance volume is derived from the reflectivity series, (the frequency spectrum is limited to the seismic bandwith lacking the low frequencies corresponding to compaction) and is called bandlimited. Impedance logs from key wells were generated, filtered to a range between 0-7 Hz and then interpolated (honoring both the stratigraphy and the structural framework) to generate a low frequency model of impedances. By merging the low frequency model with the bandlimited volume a total Acoustic impedance volume is obtained. Well data analysis describes that Acoustic impedances not only at well frequency but also at seismic frequency are visualized as maximum for sandstone packets. The acoustic impedances derived from the inversion process are sensitive to the presence of a stack of several sand units and hence can be used to map lateral variations of petrophysical reservoir properties. We have attempted to quantify the petrophysical properties of such sand sequences using extensive well control. To do so we first low-pass filtered the well logs to exhibit vertical variations consistent with those of the 3-D seismic data. The low-pass filtered logs were further analyzed via lithology-based cross-plots to ascertain their effective petrophysical properties. This procedure successfully provided us a quantitative model to predict vertical and lateral variations of petrophysical properties from seismic-derived acoustic impedances. We have also developed a similar procedure based on attributes extracted from the reflectivity data generated as by-product of the inversion process. This effectively allowed us to delineate the lateral and vertical petrophysical behavior of useful sand units for subsequent in-fill and step-out development operations. We have successfully tested this methodology on a number of new wells in the area.
942 _cCONGTP
100 1 _aMerletti, Germán
_96136
100 1 _aVictoria, Marcos
_96137
100 1 _aCourtade, Sergio F.
_92144
111 2 _aLatin American and Caribbean Petroleum Engineering Conference (7th : 2001 mar. 25-28 : Buenos Aires, Argentina)
_95738
700 1 _aVictoria, Marcos
_96137
700 1 _aCourtade, Sergio F.
_92144
711 2 _aLatin American and Caribbean Petroleum Engineering Conference (7th : 2001 mar. 25-28 : Buenos Aires, Argentina)
_95738
800 1 _aMerletti, Germán
_96136
999 _c130994
_d130994
856 _uhttps://biblioteca.iapg.org.ar/ArchivosAdjuntos/LACPEC2001/Spe69484.pdf