# US 7,609,585 B2 · Method for sub-salt migration velocity analysis > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,609,585 B2 - Document ID: US7609585B2 - Status: Granted - Kind: B2 - Application number: 11/495,445 - Filed: 2006-07-28 - Published: 2007-11-15 - Granted: 2009-10-27 - Earliest claimed: 2006-05-15 - Assignees: PGS Geophysical AS - Inventors: Junru Jiao; David Richard Lowrey; John Frier Willis; Daniel Solano - Web page: https://patentgrep.com/patent/US7609585B2 ## CPC - G01V 1/282: {Application of seismic models, synthetic seismograms} - G01V 2210/51: Migration - G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02) ## Abstract A method for interpreting seismic data below a salt layer includes depth migrating the seismic data to a bottom of the salt layer. The migrating including generating an initial model of velocities below the salt layer. The initial model is scaled by a plurality of scale factors at at least one image position. At least one of the plurality of scale factors for which a depth migrated image below the salt layer is optimum is selected as the scale factor. ## Claims ### Claim 1 A method for generating an image of subsurface formations below a salt layer from seismic data acquired therefrom, the seismic data representing signals acquired by deploying a seismic energy source and seismic sensors, actuating the source and detecting seismic energy resulting therefrom at the sensors, comprising: depth migrating the seismic data to a bottom of the salt layer, the migrating including generating an initial model of velocities below the salt layer; scaling the initial model by a plurality of scale factors at at least one image position; and selecting at least one of the plurality of scale factors for which a depth migrated image below the salt layer is optimum to generate an optimized image at the at least one image position. ### Claim 2 (depends on 1) The method of claim 1 further comprising converting the selected scale factor to interval scale factors for each of a plurality of events in the seismic data below the salt layer. ### Claim 3 (depends on 1) The method of claim 1 wherein the optimum image is determined when a peak amplitude of at least one event in the seismic data below the salt layer is at a maximum. ### Claim 4 (depends on 1) The method of claim 1 wherein the optimum image is determined when a frequency content of at least one event in the seismic data below the salt layer is at a maximum. ### Claim 5 (depends on 1) The method of claim 1 wherein the optimum image is determined when an event interpreted as a diffractor is present in a minimum number of image positions proximate the at least one image position. ### Claim 6 (depends on 1) The method of claim 1 further comprising determining a scale factor associated with an optimum image for each of a plurality of events in the seismic data below the salt layer, and determining an interval scale factor associated with each event below the salt layer. ### Claim 7 (depends on 6) The method of claim 6 further comprising determining an interval velocity to each event below the salt layer and calculating a migration depth to each event below the salt layer using the interval velocity associated therewith. ### Claim 8 (depends on 1) The method of claim 1 further comprising: selecting a plurality of image positions proximate to the at least one image position; generating a visual display of images for the plurality of image position and the at least one image position; and determining the optimum image wherein a visual appearance of the images is sharpest. ### Claim 9 A method for generating an image of subsurface formations below a salt layer from seismic data acquired therefrom, comprising: depth migrating the seismic data to a bottom of the salt layer, the migrating including generating an initial model of velocities below the salt layer, the seismic data representing signals acquired by deploying a seismic energy source and seismic sensors, actuating the source and detecting seismic energy resulting therefrom at the sensors; scaling the initial model by a plurality of scale factors at at least one image position; selecting at least one of the plurality of scale factors for which a depth migrated image below the salt layer is optimum; selecting a plurality of image positions proximate to the at least one image position; generating a visual display of images for the plurality of image position and the at least one image position; and determining the optimum image wherein a visual appearance of the images is sharpest. ### Claim 10 (depends on 9) The method of claim 9 further comprising converting the selected scale factor to interval scale factors for each of a plurality of events in the seismic data below the salt layer. ### Claim 11 (depends on 9) The method of claim 9 wherein the optimum image is determined when a peak amplitude of at least one event in the seismic data below the salt layer is at a maximum. ### Claim 12 (depends on 9) The method of claim 9 wherein the optimum image is determined when a frequency content of at least one event in the seismic data below the salt layer is at a maximum. ### Claim 13 (depends on 9) The method of claim 9 wherein the optimum image is determined when an event interpreted as a diffractor is present in a minimum number of image positions proximate the at least one image position. ### Claim 14 (depends on 9) The method of claim 9 further comprising determining a scale factor associated with an optimum image for each of a plurality of events in the seismic data below the salt layer, and determining an interval scale factor associated with each event below the salt layer. ### Claim 15 (depends on 14) The method of claim 14 further comprising determining an interval velocity to each event below the salt layer and calculating a migration depth to each event below the salt layer using the interval velocity associated therewith.