Pre-stack inversion for caved carbonate reservoir prediction: A case study from Tarim Basin, China

The major storage space types in the carbonate reservoir in the Ordovician in the TZ45 area are secondary dissolution caves. For the prediction of caved carbonate reservoir, post-stack methods are commonly used in the oilfield at present since pre-stack inversion is always limited by poor seismic data quality and insufficient logging data. In this paper, based on amplitude preserved seismic data processing and rock-physics analysis, pre-stack inversion is employed to predict the caved carbonate reservoir in TZ45 area by seriously controlling the quality of inversion procedures. These procedures mainly include angle-gather conversion, partial stack, wavelet estimation, low-frequency model building and inversion residual analysis. The amplitude-preserved data processing method can achieve high quality data based on the principle that they are very consistent with the synthetics. Besides, the foundation of pre-stack inversion and reservoir prediction criterion can be established by the connection between reservoir property and seismic reflection through rock-physics analysis. Finally, the inversion result is consistent with drilling wells in most cases. It is concluded that integrated with amplitude-preserved processing and rock-physics, pre-stack inversion can be effectively applied in the caved carbonate reservoir prediction.