US 7,321,526 B2
Method and apparatus for water velocity decomposition
Charles V. Carvill, Katy, Tex. (US); and Jonathan G. Fried, Lakewood, Colo. (US)
Assigned to WesternGeco, L.L.C., Houston, Tex. (US)
Filed on May 30, 2003, as Appl. No. 10/448,904.
Prior Publication US 2004/0240319 A1, Dec. 02, 2004
Int. Cl. G01V 1/38 (2006.01); G01V 1/36 (2006.01)
U.S. Cl. 367—21  [367/15; 367/50; 367/51] 22 Claims
OG exemplary drawing
 
11. A method of analyzing traces collected along a plurality of adjacent sail lines in a marine seismic survey area, comprising:
selecting a plurality of trace groups, at least one trace in each group sharing a common midpoint with at least one trace from another group;
determining an initial zero-offset travel time for each trace in the trace groups; and
generating a plurality of updated zero-offset travel times and a plurality of time corrections for the trace groups based on Tn(i, j, k)=To(j)+Δt(k), wherein Tn(i, j, k) represents the initial zero-offset travel times, To(j) represents the urdated zero-offset travel times and Δt(k) represents the time corrections; and
using Tn(i, j, k)=To(j)+Δt(k) to form a least-squares error function

OG Complex Work Unit Drawing
where To(j) represents the updated zero-offset travel times, Δt(k) represents the time corrections and λΣΔt(k)2 is a regularization term designed to restrict Δt(k) to small values in comparison to To(j).