Reservoirs Characterizing Based on Spectral Difference Anomaly at Lower-Frequency on Multi-Angle Stacking Gathers: Case Studies from China
Chen, Xuehua; Zhong, Wenli; He, Zhenhua
The characteristics of seismic reflection on fluid-bearing strata vary in different angle stacking gathers. One of the main characteristics is that the reflection amplitude varies with offsets, i.e. the well-known AVO (Rutherford and Williams, 1989; Castagna et al., 1998). Ghosh (2010) showed the difference of reflection amplitude is more distinctive on gas-sand strata than on dry sand. Another characteristic is that the spectral response also changes with both offsets and fluid types. Chen et al. (2008) performed spectral decomposition on far-angel stacking gathers. Their result showed that the spectral amplitude contrast between oil-sand and brine sand is remarkable, and the oil water contact (OWC) can be more easily distinguished at the lower frequency. Goloshubin et al. (2006) presented an example that a certain spectral components of AVO attributes section show bright anomalies at the reservoir.
Based on the above facts and inspired by the idea of fluid indicators (Goodway et al., 1997; Russell et al., 2003), we present a methodology and workflow to characterize reservoirs based on spectral difference anomaly at lower-frequency on multi-angle stacking gathers. We applied this methodology to both land and marine seismic datasets from China. The results show that the detected hydrocarbon accumulations are correlated well with the real gas production of wells.
AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013