This document discusses seismic data processing and describes the main processing sequences. It begins by discussing properties of IIR filters, including their general equation and transfer function. Advantages of IIR filters are using less memory than FIR filters, while disadvantages include being more susceptible to problems with finite-length arithmetic and harder to implement using fixed-point arithmetic. The document then outlines the basic processing sequence, which includes sorting seismic data through steps like CMP gathers and collecting common shot versus CMP gathers and zero-offset gathers where shots and receivers are in the same location.

1. Seismic Data Processing
Main Processing Sequence
Dr Amin Khalil
School of Physics, USM

2. Today’s Agenda
• IIR filters
And
• Main Processing Sequences

4. Properties of an IIR Filter
• The general equation of an IIR filter can be
expressed as follows:
 













M
k
k
k
N
k
k
k
M
M
N
N
za
zb
zaza
zbzbb
zH
1
0
1
1
1
10
1
1 

 ak and bk are the filter coefficients.

5. Properties of an IIR Filter
• The transfer function can be factorised to
give:
      
    
 
 zX
zY
pzpzpz
zzzzzz
kzH
N
N






21
21
 Where: z1, z2, …, zN are the zeros,
p1, p2, …, pN are the poles.

6. Properties of an IIR Filter
• The transfer function can be factorised to
give:
      
    
 
 zX
zY
pzpzpz
zzzzzz
kzH
N
N






21
21
 For the implementation of the above
equation we need the difference equation:
     
   






M
k
k
N
k
k
k
knyaknxb
knxkhny
10
0

7. Advantage
Use less memory than FIR filters
Disadvantages
•They are more susceptable to problems of finite-length arithmetic, such as
noise generated by calculations, and limit cycles. (This is a direct
consequence of feedback: when the output isn't computed perfectly and is
fed back, the imperfection can compound.)
•They are harder (slower) to implement using fixed-point arithmetic.
•They don't offer the computational advantages of FIR filters for multirate
(decimation and interpolation) applications.

8. Types of filters
Matching question.

10. Basic Processing Sequence:

13. Sorting of seismic data
This step describe the way we collect and view or
seismic data. It consists of the following:

15. CMP gather

17. Common shot vs CMP gather

18. Zero-Offset gather.
This type is applied such that both shots and receivers are at the
same location.

20. Reference for this
lecture:
Drijkoningen, G. G. and Verschuur, D.J., 2003. Seismic data processing. TU Delft.
http://geodus1.ta.tudelft.nl/PrivatePages/G.G.Drijkoningen/Lectur
eNotes/SeismicProcessing%28tg001_ta3600%29.pdf
Link

21. End
Thank you