AVO Forward Modeling Of Thin Beds Of Sandstone With Clay Content

Thin sandstone reservoirs are often encountered in oil and gas exploration and development in China.Because of the influence of clay content,saturated fluid type and thin beds,the seismic response of thin sandstone reservoirs is more complex.The identification of fluid in reservoirs has become a difficult problem in oil and gas exploration.In this paper,by means of forward modeling combined with seismic physics and numerical simulation,considering the actual reservoir and seismic parameters in the study area,and considering the factors such as different reservoir thickness,clay content and fluid saturation,two simulation areas are designed and made,including four mud-bearing reservoir models with variable reservoir parameters.Two-dimensional data of two reservoir parameter models are processed,and the wave field characteristics and AVO characteristics are analyzed.It is found that the thickness,fluid saturation type and clay content all cause AVO characteristics changes.Because of the tuning effect,the AVO response changes.The absolute values of intercept and gradient decrease with the increase of thickness.When the thickness is greater than ?/2,it will not change.The AVO response of sand body is the strongest when the thickness is close to ?/4.The change of AVO caused by the change of thickness in a small range is not affected by clay content,and the response of AVO will decrease with the increase of clay content(from 0 to 20%).For thin sandstone with clay content,saturated sandstone and saturated sandstone are located in the same area near offset.With the increase of offset,saturated sandstone will have phase inversion,which can be qualitatively analyzed.