# US 2012/0075950 A1 · Processing seismic data

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- Number: US 2012/0075950 A1
- Document ID: US20120075950A1
- Status: Published application
- Kind: A1
- Application number: 13/201,978
- Filed: 2010-01-18
- Published: 2012-03-29
- Earliest claimed: 2009-01-16
- Assignees: WesternGeco L.L.C.
- Inventors: Julian Edward Kragh; Anthony Curtis; Gabriele Busanello
- Web page: https://patentgrep.com/patent/US20120075950A1

## CPC

- G01V 1/36: Effecting static or dynamic corrections on records, e.g. correcting spread; Correlating seismic signals; Eliminating effects of unwanted energy
- G01V 1/38: specially adapted for water-covered areas (G01V1/28 takes precedence)
- G01V 2210/56: De-ghosting; Reverberation compensation
- 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

Embodiments of the invention provide a method of processing marine seismic data, the data having been acquired using a “dense over/sparse under” streamer array having N over streamers disposed at a first depth and M under streamers disposed at a second depth greater than the first depth, where 0<M<N. The method comprises: a) processing seismic data for one of the over streamer target locations and seismic data for one of the under streamer target locations; b) processing seismic data for another of the over streamer target locations; and c) combining the result of (a) and the result of (b). The one of the over streamer target locations and the one of the under streamer target locations may lie in a vertical plane.

## Claims

### Claim 1

A method of processing marine seismic data, the data having been acquired at N over streamers disposed at a first depth and at M under streamers disposed at a second depth greater than the first depth, where 0<M<N, the method comprising:
a) processing seismic data for a first streamer target location and seismic data for a first under streamer target location;
b) processing seismic data for a second over streamer target location; and
c) combining the result of (a) and the result of (b).

### Claim 2 (depends on 1)

A method as claimed in claim 1 wherein processing the seismic data for the first over streamer target location and the seismic data for the first under streamer target location comprises combining the seismic data for the first over streamer target location and the seismic data for the first under streamer target location to obtain first deghosted seismic data.

### Claim 3 (depends on 2)

A method as claimed in claim 2, further comprising redatuming the combined data to the depth of the over streamers.

### Claim 4 (depends on 1)

A method as claimed in claim 1 wherein processing the seismic data for the second over streamer target location comprises deghosting the seismic data for the second over streamer target location.

### Claim 5 (depends on 1)

A method as claimed in claim 1 wherein (c) comprises adding the results of (a) below a first frequency to the results of (b) above a second frequency.

### Claim 6 (depends on 5)

A method as claimed in claim 5 wherein the first frequency is the second frequency.

### Claim 7 (depends on 5)

A method as claimed in claim 5 wherein the second frequency is zero.

### Claim 8

A method of processing marine seismic data, the data having been acquired at N over streamers disposed at a first depth and at M under streamers disposed at a second depth greater than the first depth, where 0<M<N, the method comprising:
a) applying a first processing method to seismic data for a first over streamer target location and seismic data for a second under streamer target location;
b) combining the result of (a) with seismic data for a second over streamer target location; and
c) applying a second processing method to the result of (b).

### Claim 9 (depends on 8)

A method as claimed in claim 8 wherein applying the first processing method comprises determining the up-going component of the seismic data for the first over streamer target location.

### Claim 10 (depends on 11)

A method as claimed in claim 11 further comprising determining the up-going component of the seismic data for the second over streamer target location, and wherein (b) comprises combining the up-going component of the seismic data for the first over streamer target locations and the up-going component of the seismic data for the second over streamer target location.

### Claim 11 (depends on 8)

A method as claimed in claim 8 wherein applying the second processing method comprises taking account of the signal-to-noise ratio of the combined data.

### Claim 12 (depends on 8)

A method as claimed in claim 8 wherein the second processing method comprises applying spectral balancing to the combined data.

### Claim 13 (depends on 12)

A method as claimed in claim 12 wherein applying spectral balancing comprises applying the expected ghost response of the over streamers.

### Claim 14 (depends on 8)

A method as claimed in claim 8 and comprising further processing the data obtained at (c) to obtain information about one or more parameters of the earth.

### Claim 15 (depends on 8)

A method as claimed in claim 8 wherein the seismic data for the over first and second streamer target locations and the first under streamer target locations were acquired by respective streamers disposed at the over streamer target locations and the under streamer target location.

### Claim 16 (depends on 8)

A method as claimed in of claim 8 wherein the seismic data for at least one of the first and second over streamer target locations and/or the first under streamer target locations are simulated seismic data.

### Claim 17 (depends on 8)

A method as claimed in claim 8 and comprising:
disposing a streamer array in a water column such that the array comprises N over streamers disposed at a first depth and at M under streamers disposed at a second depth greater than the first depth, where 0<M<N;
actuating a seismic source to emit energy: and
acquiring seismic data at receivers disposed on the streamers of the array.

### Claim 18 (depends on 1)

A computer-readable medium containing instructions that, when executed on a processor, cause the processor to perform a method as defined in claim 1.

### Claim 19

An apparatus for processing seismic data, the data having been acquired at N over streamers disposed at a first depth and at M under streamers disposed at a second depth greater than the first depth, where 0<M<N, the apparatus comprising:
a) a processor for processing seismic data for an over streamer target location and seismic data for an under streamer target location;
b) a processor for processing seismic data for another over streamer target location; and
c) a combiner for combining the result of (a) and the result of (b).

### Claim 20

An apparatus for processing marine seismic data, the data having been acquired at N over streamers disposed at a first depth and at M under streamers disposed at a second depth greater than the first depth, where 0<M<N, the apparatus comprising:
a) a processor for processing seismic data for an over streamer target location and seismic data for an under streamer target location;
b) a combiner for combining the output of the processor with seismic data for another over streamer target locations and
c) a processor for processing the output of the combiner.