Phase Shift Migration
Accurate subsurface images, less noise.
Wave equation migrations (WEM), which include Phase Shift and Reverse Time Migrations (RTM), resolve wave phenomena associated with complex velocity structures. The WEM Phase Shift approach is based on downward continuation of the wavefield, using a one-way wave equation solution. The Phase Shift Migration is recommended for imaging when project turnaround time does not allow for the more compute-intensive Reverse Time Migration.
PHASE SHIFT MIGRATION IS AN INTEGRAL PART OF THESE ASPENTECH SUBSURFACE SCIENCE & ENGINEERING (SSE) SOLUTIONS:
WAVE EQUATION VS. KIRCHHOFF MIGRATION
Wave Equation Migrations offer many noticeable improvements over ray-based Kirchhoff migrations. Conventional production mode Kirchhoff migrations can normally handle only a single arrival among the existing multi-arrivals, and a special correction must be applied to preserve amplitudes and phases. Wave equation migrations allow for an unlimited number of arrivals, and therefore have the potential to obtain high-fidelity images in complex areas.
HOW DOES THE PHASE SHIFT MIGRATION WORK?
Wave-equation migrations consist of two parts. The first part is a downward continuation of the wavefields, using the one-way wave equation, from shot and receiver locations. The second part is the application of an imaging condition which is the division of the downward continued receiver wavefield by the downward continued source wavefield at each image point. For the downward continuation, GeoDepth™ wave-equation migrations use the Phase Shift Plus Correction (PSPC) operator, with multi-reference velocities (we have also tested the phase-screen operator and found the PSPC to be superior in strong lateral velocity variations).
ADVANCED MIGRATIONS ASSURE HIGHEST QUALITY IMAGING
Wave Equation Migrations are available as 3D pre-stack depth migration add-on modules for GeoDepth, the AspenTech SSE velocity model building and depth imaging system.