Reservoir characterization using pre-stack inversion in one of the carbonate reservoirs of Iran

The main goal of this study is to identify different phases of existing fluids in a carbonate reservoir using seismic reservoir characterization techniques. Seismic reservoir characterization helps to find more information about reservoir rock and fluid properties in hydrocarbon exploration. The most common methods of seismic reservoir characterization are post stack, prestack and AVO (amplitude versus offset) analysis techniques. Pre-stack seismic inversion techniques produce more reliable results than post-stack inversion approaches. Pre-stack inversion methods utilize CMP gathers for inversion of seismic data. These methods invert several terms including Vp, Vs and density simultaneously. In this study, simultaneous inversion and AVO inversion were applied on pre-stack seismic data to characterize fluid distribution in the reservoir. From the AVO inversion, the intercept and gradient values were obtained, and from simultaneous inversion, Lame parameters were extracted throughout the carbonate reservoir. The obtained results were then analyzed to identify lateral fluid variations in the reservoir. After analysis of the obtained results from AVO and simultaneous inversions, it was concluded that AVO inversion was not as applicable as LMR inversion in the carbonate reservoirs.