Quantitative Analysis of Seismic Uncertainty
Earth model uncertainty assessment
Reduce event uncertainty in oil and gas reservoirs with quantitative analysis.
Joint PP-PS Inversion
Flexible joint inversion scheme for improving confidence from shear-wave data
New information and improved confidence from shear-wave data
A flexible joint inversion scheme enables a range of P-wave and S-wave data to be combined for different inversion goals. Analyzing the results from independent datasets provides additional value and reduces risk and uncertainty. For example, joint PP-PS inversion
- helps determine fracture density and orientation
- provides fluid and lithology discrimination and characterization
- enables seismic classification of PP-PS attributes
- identifies drilling hazards, including overpressure, shallow gas, and rock strength.
Independent poststack inversion can be used as a detailed check of the event correlation or as a deliverable. PS data can be inverted directly or after transformation to S reflectivity. For wide-azimuth geometries, the AVO attributes can be analyzed for azimuthal variation. An additional refinement of standard shear-wave splitting inversion can be used to show the direction and degree of tilt in tilted fracture sets.
Schlumberger offers a range of AVO and inversion technologies for conventional P-wave and joint PP-PS datasets.
Joint inversion of PP and PS data: Borehole-calibrated PP and PS angle gathers (from left to right, panels one and two) are input to a joint AVO inversion to derive P and S impedance contrasts, plus density (panels three, four, and five) and with uncertainty bounds for all three. The final, forward-modeled PP and PS angle gathers (panels six and seven) close the loop and are compared with the input data.
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