Method and device to acquire seismic data

Patent metadata

Field	Value
Publication number	US-9383470-B2
Application number	US-201314063150-A
Country	US
Kind code	B2
Filing date	Oct 25, 2013
Priority date	Oct 14, 2010
Publication date	Jul 5, 2016
Grant date	Jul 5, 2016

Abstract

Streamer and method for deploying the streamer for seismic data acquisition related to a subsurface of a body of water. The method includes a step of releasing into the body of water, from a vessel, a body having a predetermined length together with plural detectors provided along the body; a step of towing the body and the plural detectors such that the plural detectors are submerged; and a step of configuring plural birds provided along the body, to float at a predetermined depth from a surface of the water such that a first portion of the body has a curved profile while being towed underwater.

First claim

What is claimed is:

1. A streamer for collecting seismic data related to a subsurface of a body of water, the streamer comprising:
a body having first and second portions;
plural detectors provided along the body; and
plural birds distributed along the first portion of the body,
wherein the plural birds are configured to position the body, when deployed under water, at predetermined depths from a surface of the water to impart to the first portion of the body a predetermined, variable-depth profile while being towed underwater.

2. The streamer of claim 1 , wherein the variable-depth profile is one of a parabola, a circle or a hyperbola.

3. The streamer of claim 1 , wherein the plural birds are also distributed along the second portion to achieve a flat profile of the second portion.

4. The streamer of claim 1 , wherein the non-linear, variable-depth profile is parameterized and described by z(h), which is a depth of a point of the first portion relative to the surface of the water, and satisfies the following equation:

z
⁡

(
h
)

=

z
0

+

s
0

⁢

h
⁡

(

1
-

0.5
⁢

(

h

h
c

)

)

⁢

⁢
for
⁢

⁢
h

≤

h
c

,

where h is a horizontal distance between the point and a first detector provided on the body, z 0 is a depth of the first detector relative to the surface of the water, s 0 is a non-zero slope of the body at the first detector of the streamer, and h c is a predetermined horizontal distance between the first detector and an end of the non-linear, variable-depth profile.

5. The streamer of claim 4 , wherein the second portion is described by equation z(h)=z 0 +s 0 ·0.5·h c for h>h c .

6. The streamer of claim 4 , wherein a projection of the entire body on a line substantially parallel to the surface of the water is less than h c .

7. The streamer of claim 1 , wherein the non-linear, variable-depth profile stays substantially the same during the towing.

8. The streamer of claim 1 , wherein the plural detectors include hydrophones and accelerometers.

9. A method for seismic data acquisition related to a subsurface of a body of water, the method comprising:
towing a body having plural detectors distributed along the body;
configuring plural birds along a first portion of the body, to position the body at predetermined depths from a surface of the water to impart to the first portion of the body a predetermined, variable-depth profile while being towed underwater; and
recording with the plural detectors the seismic data while towing the body.

10. The method of claim 9 , wherein the profile is a parabola, a circle or a hyperbola.

11. The method of claim 9 , wherein a second portion of the streamer has a flat profile and is connected to the first portion.

12. The method of claim 9 , wherein the non-linear, parameterized, variable-depth profile is described by z(h), which is a depth of a point of the first portion relative to the surface of the water, and satisfies the following equation:

z
⁡

(
h
)

=

z
0

+

s
0

⁢

h
⁡

(

1
-

0.5
⁢

(

h

h
c

)

)

⁢

⁢
for
⁢

⁢
h

≤

h
c

,

where h is a horizontal distance between the point and a first detector provided on the body, z 0 is a depth of the first detector relative to the surface of the water, s 0 is a non-zero slope of the body at the first detector of the streamer, and h c is a predetermined horizontal distance between the first detector and an end of the non-linear, variable-depth profile.

13. The method of claim 12 , further comprising:
towing a second portion, connected to the first portion, the second portion being described by equation z(h)=z 0 +s 0 ·0.5·h c for h>h c .

14. The method of claim 9 , wherein the plural detectors include hydrophones and accelerometers.

15. A method for processing seismic data acquired with a variable-depth profile streamer, the method comprising:
towing a body having plural se

Assignees

• Cgg Services Sa

Inventors

• Soubaras Robert

Classifications

• G01V1/3817 Primary

  Positioning of seismic devices · CPC title

• G01V1/3826 Primary

  dynamic steering, e.g. by paravanes or birds · CPC title