Three-dimensional seismic survey methods using a perturbation pattern to provide bin fractionation
View Patent ↗A receiver point arrangement is deployed having one or more receiver lines, each receiver line having receivers with substantially uniform inline spacing. A seismic source is triggered at each source point in an arrangement of source points along one or more source lines, each source line having source points with substantially uniform crossline spacing. Seismic data traces are collected, each trace having an associated midpoint. A perturbation pattern is applied to at least one of the receiver point arrangement and the source point arrangement to distribute the midpoints evenly within a bin having dimensions of half the receiver inline spacing and half the source crossline spacing across multiple locations within that bin. The fractionation in the crossline and inline directions is determined by the interaction between the number of offset positions in the receiver point arrangement and number of offset positions in the source point arrangement, respectively; phase shifts of the perturbation pattern between adjacent receiver lines and between adjacent source lines, respectively; and crossline and inline fold, respectively, of a recording patch employed.
1. A method for providing even or uniform bin-fractionation for a three-dimensional seismic survey, comprising:
deploying a receiver point arrangement having one or more receiver lines, each receiver line having receivers with substantially uniform inline spacing;
triggering a seismic source at each source point in an arrangement of source points along one or more source lines, each source line having source points with substantially uniform crossline spacing; and
collecting seismic data traces, each trace having an associated midpoint,
wherein a perturbation pattern is applied to at least one of the receiver point arrangement and the source point arrangement to distribute the midpoints evenly within a bin having dimensions of half the receiver inline spacing and half the source crossline spacing across multiple locations within that bin, in which the fractionation in the crossline and inline directions is determined by the interaction between the number of offset positions in the receiver point arrangement and number of offset positions in the source point arrangement, respectively; phase shifts of the perturbation pattern between adjacent receiver lines and between adjacent source lines, respectively; and crossline and inline fold, respectively, of a recording patch employed.
2. The method of claim 1 , wherein the fractionation in the crossline and inline directions is further determined by the ratios of a period of the receiver line perturbation pattern to an interval between source lines and the period of the source line perturbation pattern to an interval between receiver lines, respectively.
3. The method of claim 1 , wherein the perturbation pattern is applied to the receiver point arrangement.
4. The method of claim 3 , wherein the receiver point arrangement comprises multiple receiver lines each having the perturbation patter, and wherein the perturbation patterns for adjacent receiver lines have a nonzero phase shift.
5. The method of claim 1 , wherein the perturbation pattern is applied to the source point arrangement.
6. The method of claim 5 , wherein the source point arrangement comprises multiple source lines each having the perturbation pattern, and wherein the perturbation patterns for adjacent source lines have a nonzero phase shift.
7. The method of claim 1 , wherein the pattern is a triangular wave pattern.
8. The method of claim 1 , wherein the pattern is a stair-step pyramid pattern.