Seismic Data Processing
Code: ZGE 373/4
2013/2014
Dr. Amin E. Khalil
Syllabus
1- Mathematical Basis for Fourier transform
2- Sampling considerations of seismic time series
3- Main processing sequence
4- Velocity analysis
5- Deconvolution, convolution, filtering and migration in space and time (prestack).
6- Acquisition of seismic data ( land and sea).
7- 3-D seismic data processing
8- Radon transform, tau-p processing, Hilbert transform and AVO
Refernces

1- Yilmaz, O., 2001. Seismic Data Processing. Soceity of Exploration
Geophysicist (SEG)
2- Mayeda, W., 1993. Digital Signal Processing. Prentice-Hall.
Why Seismic Data Processing is important?

Because reflection seismic energy arrive later, it might be obscured by
another seismic signals like ground roll and direct waves. Hence we apply
Seismic data Processing
1- To remove unwanted Signals and Noises
2- To Enhance Signal to Noise ratio
Illustration of The Problem
Part One
Mathematical Basis for Fourier transform

•
•

Complex Numbers
Vectors

•

Matrices

•
•

Linear vector spaces
Linear systems

•
•
•
•

Determinants
Eigenvalue problems
Singular values
Matrix inversion

•
•
•

Series
Taylor
Fourier
Delta Function
Fourier integrals

•
•

The idea is to illustrate these
mathematical tools with
examples from seismology
Lecture One

Complex Numbers
●

●

Representation
●

●

Definition
Operations

Complex Conjugate
●

Importance
Complex numbers; Definition & operations
Definition:

A combination of a real and an imaginary number in the form a + bi,
where a and b are real, and i is the "unit imaginary number" √(-1),
The values a and b can be zero.
Examples:

1 + i, 2 - 6i, -5.2i, 4
imaginary number is that real number that give negative number
when it’s squared
Representation of complex numbers
Complex numbers: Basic Operations
Complex numbers are "binomials" of a sort, and are added, subtracted, and multiplied in a similar
way.

◄ Equality:
Two complex numbers
are equal if and only if their
real parts are equals and
their imaginary parts are
Equal.
Ex: 3 – 4i = x + yi
yields that x=3 and y=-4

◄ Addition and subtraction
Addition and subtraction is
done such that real parts are
added (subtracted) together
and same for imaginary parts.
Ex: two complex numbers
Z1=a + bi and Z2=c+di are
added in the form
Z1 + Z2= (a+c) + (b+d)i

◄ Multiplication is done
similar to binomial
multiplication.
Ex: Z1 * Z2 =
ac+adi+cbi-bd
simplified as:
(a c - b d) + (a d + c b) i
Complex Numbers: complex Conjugate
A complex conjugate is that number which when multiplied
with original one the result is real number. In this case the
real and imaginary parts for both numbers but the sign of
the imaginary part is reversed in such a wa that if the
complex number Z = a + b i then its complex conjugate is
Z* = a - b i. We use * supersccipt to denote complex
conjugate. The multiplication Z*Z= a2 - b2
Complex Numbers: Subdivision
Subdividing two complex numbers Z1 and Z2 is done using the
complex conjugate property, that results in the vanishing of the
imaginary part from the denumerator. Then division is carried out.
Ex.:
Solve
Sol.: First multiply by the
conjugate of the denumerator

then
Uses of complex numbers in Seismology

•
•
•
•

Discretizing signals, description with exp(iwt)
Poles and zeros for filter descriptions
Elastic plane waves
Analysis of numerical approximations
Vectors

•

Linear Vector Spaces.

•

Linear Systems.
Linear Vector Spaces
For discrete linear inverse problems we will need the concept of linear vector spaces. The
generalization of the concept of size of a vector to matrices and function will be extremely
useful for inverse problems.
Definition: Linear Vector Space. A linear vector space over a field F of
scalars is a set of elements V together with a function called addition
from VxV into V and a function called scalar multiplication from FxV into
V satisfying the following conditions for all x,y,z ∈ V and all a,b ∈ F
1.
2.
3.
4.
5.
6.
7.
8.

(x+y)+z = x+(y+z)
x+y = y+x
There is an element 0 in V such that x+0=x for all x ∈ V
For each x ∈ V there is an element -x ∈ V such that x+(-x)=0.
a(x+y)= a x+ a y
(a + b )x= a x+ bx
a(b x)= ab x
1x=x
Comparing Vectors
Linear System of Algebraic Equations

... where the x1, x2, ... , xn are the unknowns ...
in matrix form
Ax = b
System of Linear Algebraic Equations (continued)

where

A is a nxn (square)
matrix, and x and b are
column vectors of
dimension n
Matrix
A matrix is a collection of numbers arranged into a fixed number of rows and columns.
Usually the numbers are real numbers. In general, matrices can contain complex
numbers but we won't see those here. Here is an example of a matrix with three rows
and three columns:

A matrix can be subdivided into column vectors or raw vectors
Matrix Operations
Row vectors

Column vectors

Matrix addition and subtraction
Matrix multiplication
where A (size lxm) and B (size mxn) and i=1,2,...,l and
j=1,2,...,n.
Note that in general AB≠BA but (AB)C=A(BC)
Matrix Operations
Transpose

Symmetric Matrix

Identity matrix

with AI=A, Ix=x
Orthogonal Matrix
It is such that when multiplied with its transpose the result is the identity
matrix I.e:
AAT=I
Where AT is the transpose of matrix A.
In particular, an orthogonal matrix is always invertible, and
A-1=AT
Matrix Norm
How can we compare the size of vectors, matrices (and functions!)?
For scalars it is easy (absolute value). The generalization of this concept to vectors, matrices
and functions is called a norm. Formally the norm is a function from the space of vectors into
the space of scalars denoted by

∥A∥
with the following properties:

Definition: Norms.
1.
2.
3.

||v|| > 0 for any v∈0 and ||v|| = 0 implies
v=0
||av||=|a| ||v||
||u+v||≤||v||+||u|| (Triangle inequality)

We will only deal with the so-called lp Norm.
Thank you

End of Lecture

Seismic data processing introductory lecture

  • 1.
    Seismic Data Processing Code:ZGE 373/4 2013/2014 Dr. Amin E. Khalil
  • 2.
    Syllabus 1- Mathematical Basisfor Fourier transform 2- Sampling considerations of seismic time series 3- Main processing sequence 4- Velocity analysis 5- Deconvolution, convolution, filtering and migration in space and time (prestack). 6- Acquisition of seismic data ( land and sea). 7- 3-D seismic data processing 8- Radon transform, tau-p processing, Hilbert transform and AVO
  • 3.
    Refernces 1- Yilmaz, O.,2001. Seismic Data Processing. Soceity of Exploration Geophysicist (SEG) 2- Mayeda, W., 1993. Digital Signal Processing. Prentice-Hall.
  • 4.
    Why Seismic DataProcessing is important? Because reflection seismic energy arrive later, it might be obscured by another seismic signals like ground roll and direct waves. Hence we apply Seismic data Processing 1- To remove unwanted Signals and Noises 2- To Enhance Signal to Noise ratio
  • 5.
  • 6.
  • 7.
    Mathematical Basis forFourier transform • • Complex Numbers Vectors • Matrices • • Linear vector spaces Linear systems • • • • Determinants Eigenvalue problems Singular values Matrix inversion • • • Series Taylor Fourier Delta Function Fourier integrals • • The idea is to illustrate these mathematical tools with examples from seismology
  • 8.
  • 9.
    Complex numbers; Definition& operations Definition: A combination of a real and an imaginary number in the form a + bi, where a and b are real, and i is the "unit imaginary number" √(-1), The values a and b can be zero. Examples: 1 + i, 2 - 6i, -5.2i, 4 imaginary number is that real number that give negative number when it’s squared
  • 10.
  • 11.
    Complex numbers: BasicOperations Complex numbers are "binomials" of a sort, and are added, subtracted, and multiplied in a similar way. ◄ Equality: Two complex numbers are equal if and only if their real parts are equals and their imaginary parts are Equal. Ex: 3 – 4i = x + yi yields that x=3 and y=-4 ◄ Addition and subtraction Addition and subtraction is done such that real parts are added (subtracted) together and same for imaginary parts. Ex: two complex numbers Z1=a + bi and Z2=c+di are added in the form Z1 + Z2= (a+c) + (b+d)i ◄ Multiplication is done similar to binomial multiplication. Ex: Z1 * Z2 = ac+adi+cbi-bd simplified as: (a c - b d) + (a d + c b) i
  • 12.
    Complex Numbers: complexConjugate A complex conjugate is that number which when multiplied with original one the result is real number. In this case the real and imaginary parts for both numbers but the sign of the imaginary part is reversed in such a wa that if the complex number Z = a + b i then its complex conjugate is Z* = a - b i. We use * supersccipt to denote complex conjugate. The multiplication Z*Z= a2 - b2
  • 13.
    Complex Numbers: Subdivision Subdividingtwo complex numbers Z1 and Z2 is done using the complex conjugate property, that results in the vanishing of the imaginary part from the denumerator. Then division is carried out. Ex.: Solve Sol.: First multiply by the conjugate of the denumerator then
  • 14.
    Uses of complexnumbers in Seismology • • • • Discretizing signals, description with exp(iwt) Poles and zeros for filter descriptions Elastic plane waves Analysis of numerical approximations
  • 15.
  • 16.
    Linear Vector Spaces Fordiscrete linear inverse problems we will need the concept of linear vector spaces. The generalization of the concept of size of a vector to matrices and function will be extremely useful for inverse problems. Definition: Linear Vector Space. A linear vector space over a field F of scalars is a set of elements V together with a function called addition from VxV into V and a function called scalar multiplication from FxV into V satisfying the following conditions for all x,y,z ∈ V and all a,b ∈ F 1. 2. 3. 4. 5. 6. 7. 8. (x+y)+z = x+(y+z) x+y = y+x There is an element 0 in V such that x+0=x for all x ∈ V For each x ∈ V there is an element -x ∈ V such that x+(-x)=0. a(x+y)= a x+ a y (a + b )x= a x+ bx a(b x)= ab x 1x=x
  • 17.
  • 18.
    Linear System ofAlgebraic Equations ... where the x1, x2, ... , xn are the unknowns ... in matrix form Ax = b
  • 19.
    System of LinearAlgebraic Equations (continued) where A is a nxn (square) matrix, and x and b are column vectors of dimension n
  • 20.
    Matrix A matrix isa collection of numbers arranged into a fixed number of rows and columns. Usually the numbers are real numbers. In general, matrices can contain complex numbers but we won't see those here. Here is an example of a matrix with three rows and three columns: A matrix can be subdivided into column vectors or raw vectors
  • 21.
    Matrix Operations Row vectors Columnvectors Matrix addition and subtraction Matrix multiplication where A (size lxm) and B (size mxn) and i=1,2,...,l and j=1,2,...,n. Note that in general AB≠BA but (AB)C=A(BC)
  • 22.
  • 23.
    Orthogonal Matrix It issuch that when multiplied with its transpose the result is the identity matrix I.e: AAT=I Where AT is the transpose of matrix A. In particular, an orthogonal matrix is always invertible, and A-1=AT
  • 24.
    Matrix Norm How canwe compare the size of vectors, matrices (and functions!)? For scalars it is easy (absolute value). The generalization of this concept to vectors, matrices and functions is called a norm. Formally the norm is a function from the space of vectors into the space of scalars denoted by ∥A∥ with the following properties: Definition: Norms. 1. 2. 3. ||v|| > 0 for any v∈0 and ||v|| = 0 implies v=0 ||av||=|a| ||v|| ||u+v||≤||v||+||u|| (Triangle inequality) We will only deal with the so-called lp Norm.
  • 25.