ISTANBUL UNIVERSITY
ASSOCIATE PROF.DR. HÜSEYİN TUR
Basic seismic
interpretation
RECORDING SEISMIC DATA
Compressional (P) and Shear (S) waves


P wave: the fastest
kind of seismic
wave. The P wave
can move through
solid rock and
fluids
S wave: slower
than a P wave and
can only move
through solid rock
Surface/
seafloor
P-wave
Source
CMP
CCP
Reflector
Transmitted P and
SV waves
3C/4C
Receiver
Basic reflection theory


Refected and Transmitted waves
Reflection coefficient
the velocity increases across the
interface the reflection coefficient
will be positive (peak)
RC's are negative when moving
from a high velocity to a low
velocity (trough)
Phase: Refers to the SHAPE of a
wavelet
Polarity: Only has positive and
negative conditions
Bright Spot Dim spot and Flat Spot



Bright spot is preresented
with high ampliture
indicacate low velocity gas
sand. Sometime bright spot
may exist because of some
lithologic variation
Dim spot have nearly the
same velocity between two
layers.
Flat spot is a reflection from
the flat upper surface of a
liquid, that is a contact
between a liquid and a gas.
Only recognizable when the
other reflections around it
are not flat
Velocity
Some factors effect to velocity:
Compaction (depend on depth)
Lithology (limestone>sandstone)
Porosity
Pore fluid type (H2O>Oil>Gas)
Geologic age
Workflow
Geology
2D Seismic data acquisition
3D seismic data acquisition
Seismic data processing
Seismis data interpretation
Time to depth conversion
Location to Drill
Seismic data interpretation
Interpretation workflow (3D)
IESX
Display basemap
and seis2Dv/3Dv
Interpret
faults
Interpret horizons,
create fault contacts
Create fault
boundaries
Grid and
Contour map
CPS-3
Time to depth
conversion
Depth map
Volumetric
calculation
Location
To drill
Display Basemap
2D line
3D Survey
3D
nline) Crossline: 500-770, Increment: 20
2D
CDP increment: 50
Display Seis2DV/3DV

Display style:
VI: variable intensity
wiggle trace
VA
VI
IN-LINE AND CROSS-LINE
Source Points
4C Receivers
In-line Geophone
N

Cross-line Geophone
Method to pick the Faults
Inline 570: parallel to Fault strike
Crossline 570: perpendicular to Fault strike
Interpret Faults
Fault location
Interpret Horizons
Horizon_1
Horizon_2
Create fault boundaries
Fault_3
Fault_2
Horizon_2
Horizon_1
Fault_1
Grid and Contour Horizon_1
Time map with Fault boundaries
Time map with no Fault boundaries
Time: 680-770 (ms)
Gridding>structural Gridding
Grid and Contour Horizon_2
Time map with Fault boundaries
Time map no fault boundaries
Time: 940-1110 (ms)
Time to Depth Conversion
time to depth conversion
y = -1E-14x 5 + 1E-10x 4 - 4E-07x 3 +
0.001x 2 + 2.3851x + 0.4211
16000
Series1
Series2
Series3
Series4
Series5
14000
Series6
Series7
Series8
12000
Series9
Series10
Series11
10000
Series12
Depth
Series13
Series14
8000
Series15
Series16
Series17
6000
Series18
Series19
Series20
4000
Series21
Series22
Series23
2000
Series24
Series25
Series26
0
0
1000
2000
Time
3000
4000
Series27
Series28
Poly. (Series28)
Create Depth Map
Horizon_1: 1959-2265 (ft)
Interval: 20 (ft)
Horizon_2: 2900-3536 (ft)
Interval: 25 (ft)
Location to drill
drill
model
seismic