Migration Velocity Modeling for Common Imaging Point Gathers by the Wave Equation Method

Abstract

The imaging result of prestack depth migration (Pre‐SDM) is quite sensitive to migration velocity field. Reasonable migration velocity modeling becomes the key to obtain the Pre–SDM imaging with high quality. Firstly, common imaging point (CIP) gathers are extracted by using wave equation Pre‐SDM with high imaging precision. Then, based on the perturbation method, the quantitative relationship between the errors in migration velocity and those in imaged depths is established through a parameterized velocity function and the modified residual curvature analysis (RCA). Finally, migration velocity modeling is realized by using single/multi parameter joint‐iteration inversion. The test on the Marmousi model shows that the method proposed in this paper has a stronger adaptability and better modeling and imaging results for a complex geological body, and it needs only to analyze and control the main reflectors through 3 to 4 iterations to meet the required precision.

Residual curvature migration velocity analysis for angle domain common imaging gathers

“…So far the RCA methods used today are all developed from AlYahya's work. For example, Liu and Bleistein (1995), Liu (1997) and Li, et al (2003) separately proposed the perturbation method on Kirchhoff offset domain CIGs (ODCIGs) and established the quantitative relationship between the errors in migration velocity and those in imaged depth through the parameterized velocity function and the modified RCA methods. Prucha et al (1999) and Jiao et al (2002) proposed a velocity scanning method on ray-parameter CIGs (PhCIGs).…”