Rock property modeling offers organizing and visualizing geology and geophysical data for prioritizing projects.
Porosity modeling | |
XXX Well Logs | Typical AVO Responses |
The XXX well logs could be similar to typical Gulf Coast gas sand AVO responses.
The target reservoirs could be the sands of the Early-Mid Miocene formations between 1.0 –3.0 sec. two-way time.
AVO Workflow
(1) Pre-Stack Depth Migration (PSDM) (2) Final PSDM Migration Velocity Analysis (MVA) (3) Convert from Offset to Angle Gathers using MVA velocities (4) AVO Attributes Computation
AVO Attributes
(1) Intercept = the P-wave reflection amplitude at zero offset that is related to acoustic impedance and porosity (2) Gradient = the P-wave reflection amplitude minus twice the S-wave reflection amplitude, that is related to fluid saturation in reservoir rocks (3) Poisson’s ratio = the sum of the intercept and the gradient is the approx. Poisson’s ratio change, which is an indicator of fluid saturation (4) S-wave = the difference of the intercept and the gradient, after scaling, is the approximate S-wave reflectivity
Seislink Recommendations
Interval Velocity in Depth Domain
It is recommended to use seismic PSDM / PSTM stacked volumes, velocity data for pore pressure prediction, and AVO attributes to interpret the 3D structures and the related amplitude anomalies for the reservoir estimation. A new 3D seismic survey with denser bin size should be acquired to avoid the data aliasing effects on the steep-dip events and to monitor the reservoir changes.