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 PP-PS inversion using borehole-calibrated multicomponent data.

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.