Seismic acquisition method and apparatus

Patent metadata

Field	Value
Publication number	US-2016187516-A1
Application number	US-201514957346-A
Country	US
Kind code	A1
Filing date	Dec 2, 2015
Priority date	Dec 2, 2014
Publication date	Jun 30, 2016
Grant date	—

Abstract

A technique for use in geophysical surveying acquires seismic data at low seismic frequencies to generate better starting models for subsurface attributes rather than enhancing the bandwidth of airguns for broadband imaging as in conventional practice.

First claim

What is claimed is:

1 . A method for use in a marine seismic survey, comprising:
deploying a receiver array in which the nodes are spaced on the water bottom ≧400 m apart with at least one source-receiver offset of ≧15 km; towing a seismic source at a depth ≧30 m along a plurality of shot lines spaced apart ≧400 m; and imparting a plurality of low-frequency seismic signals having a frequency <4 Hz from the seismic source as the seismic source is towed along the shot lines.

2 . The method of claim 1 , wherein deploying the receiver array includes deploying a receiver array in which the nodes are spaced apart at ≧750 m on the water bottom along at least one axis.

3 . The method of claim 2 , wherein deploying the receiver array in which the nodes are spaced apart at ≧750 m includes deploying a receiver array in which the nodes are spaced apart ˜2 km on the water bottom along at least one axis.

4 . The method of claim 1 , wherein deploying the receiver array in which the nodes are spaced with at least one source-receiver offset of ≧15 km includes deploying a receiver array in which the nodes are spaced with at least one source-receiver offset of between ˜15 km and ˜30 km.

5 . The method of claim 1 , wherein towing the seismic source at the depth of ≧30 m includes towing a source at a depth of ˜30 m to ˜60 m.

6 . The method of claim 1 , wherein towing the seismic source includes towing a source where the tow cable deviates ≦±10° off the vertical normal to the water bottom.

7 . The method of claim 1 , wherein towing the seismic source includes:
stopping a vessel from which the source is towed; and imparting the seismic signals from the seismic source at the point at which the vessel is stopped.

8 . The method of claim 1 , wherein towing the seismic source includes towing a seismic source from the side of the vessel.

9 . The method of claim 1 , wherein imparting the seismic signals includes imparting the plurality of seismic signals from the seismic source at a single point.

10 . A method for use in a seismic survey, comprising:
deploying a receiver array in which the nodes are spaced on the water bottom at ≧750 m along at least one axis with at least one source-receiver offset of 15 km; towing a seismic source along a plurality of shot lines; and imparting a plurality of seismic signals from the seismic source as the seismic source is towed along the shot lines.

11 . The method of claim 10 , wherein deploying the receiver array includes deploying a receiver array in which the nodes are spaced apart at ≧2 km on the water bottom along at least one axis.

12 . The method of claim 11 , wherein deploying the receiver array in which the nodes are spaced apart at ≧2 km on the water bottom along at least one axis includes deploying a receiver array in which the nodes are spaced apart ˜4 km on the water bottom along at least one axis.

13 . The method of claim 10 , wherein deploying the receiver array in which the nodes are spaced with at least one source-receiver offset of ≧15 km includes deploying a receiver array in which the nodes are spaced with at least one source-receiver offset of up to ˜30 km.

14 . A method for use in a marine seismic survey, comprising:
deploying a receiver array on the water bottom; towing a seismic source at a depth ≧30 m along a plurality of shot lines spaced apart ≧400 m; and imparting a plurality of seismic signals from the seismic source as the seismic source is towed along the shot lines.

15 . The method of claim 14 , wherein towing the seismic source along a plurality of shot lines includes towing the seismic source along a plurality of shot lines spaced apart at ≧750 m.

16 . The method of claim 14 , wherein towing the seismic source at the depth of ≧30 m includes towing a seismic source at a depth of ≧60 m.

17 . The method of claim 14 , wherein towing the seismic source includes towing a source at a depth at which the tow cable deviates ≦±10° off the vertical normal to the water bottom.

18 . The method of claim 14 , wherein towing the seismic source includes towing a seismic source from the side of a vessel.

19 . The method of claim 14 , wherein imparting the seismic signals from the seismic source includes imparting the seismic signal from the seismic source at a single point.

20 . A method for use in a seismic survey, comprising:
deploying a receiver array on the water bottom; towing a seismic source along a plurality of shot lines; and imparting a plurality of seismic signals from the seismic source as the seismic source is towed along the shot lines, including imparting the seismic signals from the seismic source at a point at which a vessel towing the seismic source is stopped.

21 . The method of claim 20 , wherein towing the seismic source includes towing the seismic source from the side of the vessel.

22 . A method for use in a marine seismic survey, including:
deploying a plurality of seismic receivers on the water bottom, the seismic receivers being attached to a positively buoyant element; and retrieving the seismic receivers, including:
towing a grappling device across the positively buoyant element; and
grappling the positively buoyant element.

23 . The method of claim 22 , wherein the positively buoyant element comprises a buoy.

24 . The method of claim 22 , wherein deploying the seismic receivers includes deploying a plurality of receivers from a basket coupled to a remotely operated vehicle within tens of meters from the water bottom.

Assignees

• Bp Corp North America Inc

Inventors

• Brenders Andrew James
• Dellinger Joseph Anthony
• Etgen John Theodore
• Openshaw Graham
• Ross Allan

Classifications

• G01V1/005

  with exploration systems emitting special signals, e.g. frequency swept signals, pulse sequences or slip sweep arrangements · CPC title

• G01V1/3852

  to the seabed · CPC title

• G01V1/3808 Primary

  Seismic data acquisition, e.g. survey design · CPC title

• G01V1/3843

  Deployment of seismic devices, e.g. of streamers (equipment for marine deployment in general B63B) · CPC title