Method for simultaneous collection of seismic data from shallow and deep targets

• US 5,148,406 A
• Filed: 05/25/1990
• Issued: 09/15/1992
• Est. Priority Date: 05/31/1989
• Status: Expired due to Term

• Current Assignee: GECO AS
• Original Assignee: GECO AS
• Inventors: Gateman, Jan, Brink, Munday
• Primary Examiner(s): Moskowitz, Nelson
• Application Number:
  US07/528,213
• Time in Patent Office: 844 Days
• Field of Search: 367/15, 367/20, 367/22, 367/49, 367/62, 364/421, 364/223.9, 364/924.5
• US Class Current: 367/22
• CPC Class Codes: G01V 1/28 Processing seismic data, e.g. for interpretation or for event detection G01V1/48 takes precedence
• CPC Class Codes: G01V 1/3808 Seismic data acquisition, e.g. survey design
• CPC Class Codes: G01V 2210/20 Trace signal pre-filtering to select, remove or transform specific events or signal components, i.e. trace-in/trace-out removing noise G01V2210/32

Abstract

A method for simultaneous collection of seismic data of shallow and deep targets, in which two seismic streamers are towed at different water depths (1 and 2 in FIG. 2), and only one acoustic source of seismic signals is used. The seismic data recorded by the different streamers are mixed in a subsequent processing step, seismic data being weighted before being mixed by a weight which is made dependent on the recorded two-way travel time for the respective streamers, so that data from one or several streamers located at the least water depth receive a weight which decreases with travel time, whereas data from a corresponding number of streamers of greater depths receive a weight which increases with travel time.

Claims

1. In a method for simultaneous collection of seismic data of shallow and deep targets, wherein at least two seismic streamers are towed by a vessel at a different water depth, and only one acoustic source for the seismic signals is used, the improvement comprising:

weighting seismic data recorded by different seismic streamers with a weight which is made dependent on two-way travel time recorded by the respective steamers so that data from at least one streamer positioned at the least water depth receives a weight decreasing with travel time, and data from a corresponding number of streamers at a greater water depth receive a weight increasing with travel time; and

mixing said seismic data from said different seismic streamers.

2. A method as claimed in claim 1, and further comprising:

relating and associating said two-way travel time with a certain geological structure.

3. A method as claimed in claim 1, and further comprising:

correcting said recorded seismic data to a plane of reference before said mixing.

4. A method as claimed in claim 3, and further comprising:

carrying out said mixing immediately after said correcting to the plane of reference.

5. A method as claimed in claim 1, and further comprising:

after said weighting and before said mixing stacking said data to reduce the amount of data recorded by a streamer to only one time series for each surface point.

6. A method as claimed in claim 4, and further comprising:

relating and associating said two-way travel time with a certain geological structure.

7. A method as claimed in claim 2, and further comprising:

after said weighting and before said mixing stacking said data to reduce the amount of data recorded by a streamer to only one time series for each surface point.

8. A method as claimed in claim 3, and further comprising:

after said weighting and before said mixing stacking said data to reduce the amount of data recorded by a streamer to only one time series for each surface point.