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model

The Marmousi2 model completely encapsulates the origional Marmousi model which was based on the Northern Quenguela Trough in the Quanza Basin of Angola. Lithologies include sandstones,shales, limestones and marls.

In total the Marmousi2 model is 3.5 km in depth and 17 km across. The model contains 199 horizons which make the model stratigraphicaly more complex than its predecessor. Additionally the water layer was extended to 450 meters.

As Marmousi2 is an elastic model both shear and primary velocities must be defined across the entire model. Additionally a density model is included. The files vp_marmousi-ii.segy, vs_marmousi-ii.segy, and density_marmousi-ii.segy contain the velocity and density models for Marmousi2. These three files all share the same data spacing and their headers should be formatted similarily. This header format is shown in table 2

n1=2801 o1=0 d1=0.001249 label1=Depth unit1=km  
n2=13601 o2=0 d2=0.001249 label2=Position unit2=km  

Table 2. Header information for Marmousi2 velocity and density models

The file marmousi2modelSConstruct is a SCons script that fetches the three model files (VP, VS, and Density), appends the header information as necessary and produces plots of the models. This file is reproduced in table 3 and the models themselves are shown in figures 1, 2, and 3.

from rsf.proj import *
# Fetch Files from repository
modelFiles=['vp_marmousi-ii.segy','vs_marmousi-ii.segy','density_marmousi-ii.segy']
outputFiles=['vp','vs','density']
for file in modelFiles:
    Fetch(file,"marm2")
# Convert Files to RSF
counter=0
for file in modelFiles:
    if file is 'vp_marmousi-ii.segy' or file is 'vs_marmousi-ii.segy':
        Flow(outputFiles[counter],file, ''' segyread tape=$SOURCE | put 
            d1=.001249 d2=.001249 o1=0 o2=0 label1=Depth label2=Distance
            unit1=km unit2=km''')
    if file is 'density_marmousi-ii.segy':
        Flow(outputFiles[counter],file, ''' segyread tape=$SOURCE | put 
            d1=.001249 d2=.001249 o1=0 o2=0 label1=Depth label2=Distance
            unit1=km unit2=km''')
    counter = counter+1
# Plotting Section
title=['Compressional Velocity Model','Shear Velocity Model','Density Model']
counter=0
for file in outputFiles:
    Flow(file+'small',file,'prep4plot inp=$SOURCE out=$TARGET',stdin=0,stdout=-1)
    if file is 'vp' or file is 'vs':
        Result(file,file+'small',
               '''
               grey  color=I gainpanel=a allpos=y title=%s
               scalebar=y screenratio=.205 screenht=2
               scalebar=y barlabel=Velocity barunit=km/s 
               labelsz=4 wheretitle=t titlesz=6 barreverse=y 
               ''' % title[counter])
    if file is 'density':
        Result(file,file+'small',
               '''
               grey  color=I gainpanel=a allpos=y title=%s
               scalebar=y screenratio=.205 screenht=2
               scalebar=y barlabel=Density barunit="g/cm3_"
               labelsz=4 wheretitle=t titlesz=6 barreverse=y 
               ''' % title[counter])
    counter = counter+1
End()


Table 3. SCons script generating images of the Marmousi2 model

vp
vp
Figure 1.
Marmousi2 P-wave velocity model
[pdf] [png] [scons]

vs
vs
Figure 2.
Marmousi2 S-wave velocity model
[pdf] [png] [scons]

density
density
Figure 3.
Marmousi2 Density Model
[pdf] [png] [scons]


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Next: Shots Up: Marmousi2 model Previous: Introduction

2014-07-07