Shallow Geohazard Assessment
Predrill shallow geohazard delineation
Identify, map, and delineate seafloor, shallow subsurface geologic, and constructed features.
Understand similarities and differences between PP and PS data
One of the key stages in processing multicomponent seismic data is to combine the results and interpretations from both the conventional and shear or converted wave. This facilitates interpretation of shallow high-resolution events, gives enhanced subgas and mud channel definition, and helps resolve amplitude anomalies with weak acoustic impedance contrasts.
In addition, the vertical Vp/Vs ratio or the vertical shear velocity can also be derived directly from the data, as well as shear impedance or a more accurate density estimation from Joint PP-PS inversion.
Combining the different results requires event correlation or registration of the reflectivity, impedance, or some other convenient attribute for all major boundaries, or at least for a part of the reflection sequence around the target. Initial registration can be guided by physically meaningful interval values and further attributes can be derived from these independent results to guide more detailed matching.
The correlation of P-wave and shear-wave results can be done exactly at a well location where depth and P and S velocity models are recorded, and where synthetic models can be matched to the seismic data.
At other locations, or where no well data exists, a new automated 3D registration based on nonrigid matching offers a highly detailed registration or Vp/Vs ratios.