Method of reverberation removal from seismic data and removal of dual sensor coupling errors

• US 5,754,492 A
• Filed: 02/12/1996
• Issued: 05/19/1998
• Est. Priority Date: 02/12/1996
• Status: Expired due to Term

• Current Assignee: PGS Tensor Incorporated
• Original Assignee: PGS Tensor Incorporated
• Inventors: Starr, Joel G.
• Primary Examiner(s): Moskowitz, Nelson
• Application Number:
  US08/599,717
• Time in Patent Office: 827 Days
• Field of Search: 367/21, 367/24, 181/110, 364/421
• US Class Current: 367/24
• CPC Class Codes: G01V 1/364 Seismic filtering G01V1/37 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
• CPC Class Codes: G01V 2210/56 De-ghosting; Reverberation compensation

Abstract

A method for eliminating the influence of multiple reflections in seismic data by determining an up going and down going vector wave-field from the vector wave-field, determining a product of the free surface reflection coefficient and the down going vector wavefield, and adding the product to the up going vector wave-field. Also provided is a method for eliminating the effects of receiver coupling from seismic data taken in a survey by describing a first cross-equalization filter as a function of the reverberation period, describing a second cross-equalization filter as a function of the seismic data, describing an inverse coupling filter as a function of the first cross-equalization filter and the second-equalization filter, and applying the coupling filter to the seismic data.

Claims

1. A method for eliminating free surface multiples from seismic data taken in a survey wherein there exists a free surface reflection coefficient, the method comprising:

determining an up going and a down going vector wave-field from the seismic data;

determining a product of the free surface reflection coefficient and the down going vector wave-field; and

adding the product to the up going vector wave-field.

2. A method as recited in claim 1, wherein said determining an up going and a down going vector wave-field further comprises the step of collocating seismic data receivers at a free surface.

3. A method as recited in claim 2, wherein the seismic data receivers are co-located mathematically at the free surface.

4. A method as recited in claim 2, wherein the free surface comprises an interface between air and water.

5. A method as recited in claim 2, wherein the free surface comprises a water bottom.

6. A method as recited in claim 2, wherein the seismic data receivers comprise a pressure response receiver and a particle velocity response receiver.

7. A method as recited in claim 1, wherein determining an up going and a down going vector wave-field further comprises the step of describing the seismic data as a function of the free surface reflection coefficient and a reverberation period in an expanded form.

8. A method as recited in claim 7, wherein the expanded form comprises a Z expansion.

9. A method as recited in claim 8, wherein the Z expansion comprises an exponential factor of a reverberation period.

10. A method as recited in claim 1, wherein determining an up going and a down going vector wave-field further comprises the step of describing the seismic data as a function of the free surface reflection coefficient and a reverberation period in an approximate closed form.

11. A method as recited in claim 10, wherein the seismic data comprises a first set of seismic data in the closed form and a second set of seismic data in the closed form.

12. A method as recited in claim 11, further comprising the step of adding the first set of seismic data in the closed form to the second set of seismic data in the closed form;

wherein the up going vector wave-field is defined.

13. A method as recited in claim 1, further comprising the step of subtracting the second set of seismic data in the closed form from the first set of seismic data in the closed form;

wherein the down going vector wave-field is defined.

14. A method as recited in claim 11, wherein the seismic data comprises pressure response data and particle velocity response data.