Karst Carbonate Reservoir Identification Using Frequency-dependent AVO Inversion in Tarim Basin, China

The dominate storage spaces of karst carbonate reservoir in Hadexun area, Tarim basin are dissolved pores and cavities. The influence of multi-stage structure movement makes the fluid discrimination difficult. Therefore, how to further recognise the fluid type in such reservoir is the key point. Unlike conventional post-stack methods have difficulties in fluid identification, AVOF inversion algorithm utilize P-wave dispersion property reflected by fluid to discriminate its type. Thus greatly improve the accuracy of oil exploration. In this paper, the AVOF inversion method is applied on 3D field seismic data in Hadexun area to solve the problem of fluid discrimination in karst reservoir. Field data application demonstrates that reservoirs filled up with water and hydrocarbon can be effectively separated by inverted P-wave dispersion. To be more important, by analyzing the inversion result and fault distribution, we successfully divided the faults into two groups, which are water-contained and hydrocarbon filled. In sum, the encouraging result of AVOF inversion provided robust information in karst reservoir characterization and fluid distribution, which directly offer key data for well optimization and deployment.