AVO inversion and Lateral prediction of reservoir properties of Amangi hydrocarbon field of the Niger Delta area of Nigeria

Well log modelling was performed using a complete suite of compressional, shear and density logs to understand and determine the expected angle dependent effects in the seismic reflection data and also to estimate wavelets for the different input stacks. The available well controls were used in wavelet estimation and we incorporated AVO modelling to properly account for AVO effects. We partitioned the 3D seismic reflection data into three partial angle stacks of near (0 o -10 o ), mid (11 o -20 o ) and far (21 o -30 o ). Wavelets were estimated separately for each angle stack to enable the inversion to compensate for offset dependent phase, bandwidth, tuning and normal moveout (NMO) stretch effects which could affect the amplitude and phase spectra of the data. We then simultaneously inverted multiple angle stacks to transform P-wave offset seismic reflection data to P-impedance and S-impedance volumes. These impedance volumes were interpreted separately. This method supported interpretation in this field where the reservoirs' sandstones and shales cannot be distinguished from the P-impedance alone.