Seismic data processing including compensating for source and receiver ghost effects in reverse time migration

Patent metadata

Field	Value
Publication number	US-9465125-B2
Application number	US-201313859807-A
Country	US
Kind code	B2
Filing date	Apr 10, 2013
Priority date	Apr 19, 2012
Publication date	Oct 11, 2016
Grant date	Oct 11, 2016

Abstract

Methods and systems for compensating for source and receiver ghost effects in a reverse time migration (RTM) equation are described. Boundary conditions associated with the RTM acoustic wave equations for the source and recorded wavefields are modified. The resultant modified RTM acoustic wave equations are solved to generate ghost compensated modeled seismic images. In another aspect an imaging condition is also modified and the resultant RTM acoustic wave equations are solved to generate velocity and impedance perturbation images.

First claim

What is claimed is:

1. A method, stored in a memory and executing on a processor, for compensating for ghosts in a computed seismic image based on a reverse time migration (RTM) of seismic data, said method comprising:
obtaining the seismic data acquired with one or more seismic sources and one or more seismic receivers placed to explore an underground formation;
modifying a first boundary condition of a first RTM acoustic wave equation associated with a source wavefield;
modifying a second boundary condition of a second RTM acoustic wave equation associated with a recorded wavefield;
solving said first RTM acoustic wave equation and said second RTM acoustic wave equation and generating a ghost compensated computed seismic image; and
displaying said ghost compensated computed seismic image as a structural representation of the underground formation.

2. The method of claim 1 , wherein input data used in the method in a shot domain.

3. The method of claim 1 , wherein input data used in the method in a receiver domain.

4. The method of claim 1 , wherein said first RTM acoustic wave equation is associated with said one or more seismic sources.

5. The method of claim 4 , wherein a modified first boundary condition is

p
^

F

⁡

(

x
,
y
,

z
=
0

;
ω
;

x
→

s

)

=

σ
⁡

(

x
→

-

x
→

s

)

⁢

f
⁡

(
ω
)

ⅈ
⁢

⁢
ω
⁢

⁢

G
s

⁡

(

ω
,

α
s

)

.

6. The method of claim 1 , wherein said second RTM acoustic wave equation is associated with said one or more seismic receivers.

7. The method of claim 6 , wherein a modified second boundary condition is

p
^

B

⁡

(

x
,
y
,

z
=
0

;
ω
;

x
→

s

)

=

Q
⁡

(

x
,

y
;

x
s

,

y
s

;
ω

)

G
r

⁡

(

ω
,

α
r

)

.

8. The method of claim 6 , further comprising stabilizing said second RTM acoustic wave equation for aliased seismic data.

9. The method of claim 8 , wherein said stabilization is based on a regularization remedy applied when said aliased seismic data produces instability in said second RTM acoustic wave equation.

10. The method of claim 1 , further comprising modifying an imaging condition associated with said second RTM acoustic wave equation.

11. The method of claim 10 , wherein said imaging condition is

sin
2

⁢
θ
⁢

δ
⁢

⁢
v

v

+

cos
2

⁢
θ
⁢

Assignees

• Cggveritas Services Sa
• Cgg Services Sa

Inventors

• Zhang Yu
• Roberts Graham
• Duan Lian

Classifications

• G01V2210/679

  Reverse-time modeling or coalescence modelling, i.e. starting from receivers · CPC title

• G01V1/366

  by correlation of seismic signals · CPC title

• G01V1/36 Primary

  Effecting static or dynamic corrections on records, e.g. correcting spread; Correlating seismic signals; Eliminating effects of unwanted energy · CPC title

• G01V1/375

  Correlating received seismic signals with the emitted source signal · CPC title

• G01V1/38

  specially adapted for water-covered areas (G01V1/28 takes precedence) · CPC title