Seismic data processing method
AssigneeNuTec Sciences, Inc.
InventorsZheng-Zheng Zhou, Jaime A. Stein, Michael S. Keehan
Life of this patent
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Abstract
A method for migrating seismic data is disclosed in which seismic traces recorded by a plurality of receivers are separated into offset bands according to the offsets of the traces. The data in each offset band is then migrated according to a downward continuation method. The downward continuation method includes the calculation of a constant that is not dependent on the value of the wave field. The constant is used to calculated the wave field for all offset bands for a given z level, thereby reducing time and computation resources consumed by the migration of the offset bands. Following the downward continuation, an imaging condition may be applied to produce a seismic image.
Claims19
A method for migrating seismic traces generated by a shot, comprising the steps of:
- grouping the seismic traces into a number of offset bands;
- migrating the data represented by the seismic traces of each offset band;
- and
- assigning an offset to the migrated data of each offset band.
A method for performing a downward continuation function on a grouping of traces selected according to the offset of the traces, comprising the steps of:
- collecting data representative of an up going wave field in the z direction at zero depth;
- calculating a first intermediate value on the basis of data representative of the up going wave field at zero depth;
- calculating a constant in the x direction, the value of the constant being independent of the value of the wave field;
- calculating in the x direction a second intermediate value, the value being dependent on the first intermediate value and the constant in the x direction;
- calculating a constant in the y direction, the value of the constant being independent of the value of the wave field;
- calculating in the y direction the final value of the wave field at the next depth level based on the second intermediate value and the constant in the y direction;
- repeating the above calculation steps to calculate the wave field at each successive depth level.
A method for migrating seismic traces, comprising the steps of:
- recording a series of seismic traces at a number of receivers;
- grouping the seismic traces into a number of offset bands;
- migrating the data represented by the seismic traces of each offset band according to a wave equation based downward continuation method;
- assigning an offset to the migrated data of each offset band that is equal to the midpoint of each offset band;
- and
- applying an image condition to the migrated data.
A method for migrating seismic traces recorded at a series of receivers, comprising the steps of:
- grouping the traces into a series of offset bands;
- migrating each offset band separately;
- wherein the migration for each offset band is accomplished according to a downward continuation in which the value of each following wave field in an x and y grid is determined on the basis of the value of the wave field in the preceding x and y grid and a constant that is not dependent on the value of the wave field;
- and
- wherein the constant is used for the downward continuation of all bands, thereby reducing the computational time and resources required for migration.
Dependencies are inferred from the claim text.