EEI (Extended Elastic Impedance)
Computes Extended Elastic Impedance (EEI) well curves from P-velocity, S-velocity, and density logs. Outputs log acoustic impedance (lnAI), log gradient impedance (lnGI), and a gather of EEI curves spanning a user-defined range of chi (χ) angles.
- In the Control Panel, go to View New Single Well View.
- In the Single Well window, open the Process tab.
- At the tab header, click the blue "+" icon.
- Click on EEI (Extended Elastic Impedance).
- Type a name for the process and click OK.
Configure EEI
- Input Curves:
- Velocity type: Select whether Vp and Vsa re provided as velocity or slowness curves.
- Vp: Select a P-velocity or P-slowness curve.
- Vs: Select an S-velocity or S-slowness curve.
- Density: Select a bulk density curve (g/cc).
- Chi Scan Range: Set the range and step size of chi angles for the output EEI gather. Chi angles may range from −180° to 180°. Default: 0° to 90°, step 1°.
- EEI Parameters:
- Vp0: Specify the reference P-velocity. Typically the mean or background-trend value of Vp in the zone of interest. Default: 3000 m/s.
- Vs0: Specify the reference S-velocity. Default: 1500 m/s.
- Rho0: Specify the reference bulk density (g/cc). Default: 2.5 g/cc.
- K: Set the fluid-substitution constant ≈ (Vs/Vp)². Default: 0.25.
- Output:
- Enable custom name: Specify the name of the output curves. Each curve will be named as "[output class]_[process name]" by default, or if a custom name is supplied, "[output class]_[custom name]".
- Extent: Specify the extents of the output curves.
Output
Output Curves:
- EEI: lnAI: Log acoustic impedance —EEI at χ = 0°.
- EEI: lnGI: Log gradient impedance —EEI at χ = 90°.
- EEI: Output: A gather of EEI curves, one trace per chi angle in the configured scan range (e.g.EEI: Output [0°, 90°]).