RIO GRANDE CONE TECTONO-STRATIGRAPHIC MODEL – BRAZIL: SEISMIC SEQUENCES

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ABSTRACT
The seismic analyses integrated to interpretation techniques, processing, velocity model and geophysical data
have permitted modeling different tectonic, stratigraphy or geomorphology features. This paper is the first approach to geomorphological features for a three dimensional depth model. The initial model comprises a seismic section grid with bidimensional configuration conversed to three dimensional subvolumes. These include a two and half dimensional model. Also, an attribute analyses in image section is necessary to determine the most relevant characteristics. The geomorphologic feature corresponds to the named Rio Grande Cone, which is characterized by principal tectonic and stratigraphic structures. That is why mapping and subsurface three dimensional modeling, with geology, geophysical and geomorphologic integration is necessary. The cone geomorphology is characterized by gravitational processes, bottom currents, tectonic structures and lithological compositions which are the principal factors that have been influencing it since Neogene. Then, the seismic interpretation could extract different tectonic, sedimentary structures and geoforms, for instance, faults, folds, channels, natural levee, contourites, etc.
RESUMEN
Análisis sísmicos integrados con técnicas de interpretación, procesamiento, información de velocidades y datos
geofísicos permiten modelar diferentes rasgos de tipo tectónico, estructural o geomorfológico. Este trabajo se
constituye en una primera aproximación a un modelo tridimensional de un rasgo geomorfológico ubicado en el
fondo oceánico. El modelo inicial comprende una configuración bidimensional de una grilla interpretada a partir de secciones sísmicas llevadas a un volumen tridimensional, esto mediante la concepción de una aproximación dos y medio dimensional. Además de un cambio de configuración, se hizo un análisis de atributos sobre las imágenes de las secciones y se determinaron las características presentes desde un área de la plataforma, hasta el offshore del sudeste Brasilero. El rasgo geomorfológico a tratar es conocido como el Cono de Rio Grande, el cual pudo ser caracterizando con sus principales estructuras tectónicas y estratigráficas, mediante la cartografía y modelamiento tridimensional del subsuelo, con la integración geológica, geofísica y geomorfológica. La geomorfología del cono, se ve influenciada por procesos gravitacionales, corrientes de fondo, estructuras de tipo tectónico y composición litológica, como sus principales controladores que están presentes a partir del Neógeno. Así, a partir de la interpretación sísmica pueden ser extractados diferentes estructuras tectónicas, sedimentarias y geoformas, por ejemplo presencia de fallas, pliegues, canales, levee naturales, contornitos, etc.
Publicado el : jueves, 01 de enero de 2009
Lectura(s) : 22
Fuente : Earth Sciences Research Journal 1794-6190 (2009) Vol. 13 Num. 1
Número de páginas: 12
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EARTH SCIENCES
RESEARCH JOURNAL
Earth Sci. Res. J. Vol. 13, No. 1 (June 2009): 40-53
RIO GRANDE CONE TECTONO-STRATIGRAPHIC MODEL –
BRAZIL: SEISMIC SEQUENCES
Castillo., L.L.A¹, Kazmierczak, T. de S.², and Chemale., Jr., F.³
¹ Profesor, curso de Geofísica, Departamento de Geociencias – Universidad Nacional de Colômbia Bogota.
² Schlumberger Ltd, Brazil.
³ Professor, Instituto de Geociêcias, Universidade Federal do Rio Grande do Sul, Porto Alegre – Brazil.
Corresponding author Email: lacastillol@unal.edu.co, thaissk@povo.net and farid.chemale@ufrgs.br
RESUMEN
Análisis sísmicos integrados con técnicas de interpretación, procesamiento, información de velocidades y datos
geofísicos permiten modelar diferentes rasgos de tipo tectónico, estructural o geomorfológico. Este trabajo se
constituye en una primera aproximación a un modelo tridimensional de un rasgo geomorfológico ubicado en el
fondo oceánico. El modelo inicial comprende una configuración bidimensional de una grilla interpretada a
partir de secciones sísmicas llevadas a un volumen tridimensional, esto mediante la concepción de una
aproximación dos y medio dimensional. Además de un cambio de configuración, se hizo un análisis de atributos
sobre las imágenes de las secciones y se determinaron las características presentes desde un área de la
plataforma, hasta el offshore del sudeste Brasilero. El rasgo geomorfológico a tratar es conocido como el Cono
de Rio Grande, el cual pudo ser caracterizando con sus principales estructuras tectónicas y estratigráficas,
mediante la cartografía y modelamiento tridimensional del subsuelo, con la integración geológica, geofísica y
geomorfológica. La geomorfología del cono, se ve influenciada por procesos gravitacionales, corrientes de
fondo, estructuras de tipo tectónico y composición litológica, como sus principales controladores que están
presentes a partir del Neógeno. Así, a partir de la interpretación sísmica pueden ser extractados diferentes
estructuras tectónicas, sedimentarias y geoformas, por ejemplo presencia de fallas, pliegues, canales, levee
naturales, contornitos, etc.
Palabras clave: Sismoestratigrafía, Modelamiento, tectonoestratigrafía, interpretación geofísica.
th
Manuscript receiver: February 03 , 2009.
th
Accepted for publication: June 01 , 2009.
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RIO GRANDE CONE TECTONO-STRATIGRAPHIC MODEL – BRAZIL: SEISMIC SEQUENCES
ABSTRACT
The seismic analyses integrated to interpretation techniques, processing, velocity model and geophysical data
have permitted modeling different tectonic, stratigraphy or geomorphology features. This paper is the first ap-
proach to geomorphological features for a three dimensional depth model. The initial model comprises a seismic
section grid with bidimensional configuration conversed to three dimensional subvolumes. These include a two
and half dimensional model. Also, an attribute analyses in image section is necessary to determine the most rele-
vant characteristics. The geomorphologic feature corresponds to the named Rio Grande Cone, which is charac-
terized by principal tectonic and stratigraphic structures. That is why mapping and subsurface three dimensional
modeling, with geology, geophysical and geomorphologic integration is necessary. The cone geomorphology is
characterized by gravitational processes, bottom currents, tectonic structures and lithological compositions
which are the principal factors that have been influencing it since Neogene. Then, the seismic interpretation
could extract different tectonic, sedimentary structures and geoforms, for instance, faults, folds, channels, natu-
ral levee, contourites, etc.
Key words: Seismic stratigraphy, Modeling, Tectono stratigraphy, Geophysical interpretation.
Grande Cone . This interpretation allowed the divisionIntroduction
of the deep sedimentary package into several sequences
Seismic stratigraphy method has improved since de-
and a driven-model from a sequential stratigraphy clas-
velopment of acquisition, processing and interpreta-
sification could be made. To define seismic units
tion processes. They include loading, processing,
(chronoestratigraphic unit referred as sequences), the
visualization and modeling tools that have allowed the
first step was to define the unconformities and then rec-
manipulation of format data, screen and the creation of
ognize the unit according to the facies, the seismic ex-
a high quality model. Data could be transformed to
pression and the attributes analyses.
different configurations like 2D, 2.5D and 3D.
The first concepts related to seismostratigraphy
interpretation refer to geometry and stratal termina-
tions (Mitchum et al. 1994).In the Brazil’s Southeast
area, the Rio Grande Cone has been influenced by
tectonic episodes since the Cretaceous until the Re-
cent. Two and half dimensional seismic interpreta-
tion on some sections along the surface and the
subsurface show the presence of some features lo-
cated on shelf. They include a fault system, geoforms
and folds that influence the slope, proximal and distal
shelf and the sea floor. The tectono-stratigraphyc
analysis make the description of some geological as-
pects in subsurface possible. As a consequence, a
geological model was obtained by means of the seis-
mic information and a velocity function within seis-
mic interpretation (Sarta, 2004).
Figure 1. Rio Grande Cone location within the Pelotas Ba-The geological mapping was obtained by means of
sin – Brazil (Modified from Google Earth).the seismic stratigraphic interpretation on the Rio
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CASTILLO., L.L.A, KAZMIERCZAK, T. DE S., AND CHEMALE., JR., F.
ë= V/f. (1)Geomorphology, geophysics and computational
disciplines are powerful tools that could be inte-
Then, ë = 3048m/s / 40 Hz = 76,2m, by the ë/4 => 76,2
grated in order to obtain a 3D approach by using a m/4 = 19,05m => 62,5 feet.
driven-model method. This model allows the genera-
These calculations determined that the obtainedtion of a more realistic feature of the subsurface geo-
thickness for a minimum layer is between 20 to 100morphology. In this preliminary research a 3D model
feet (7 to 30m), otherwise it is not tuned. The seismicobtained from seismic interpretation in the Rio
resolution limit in section data establishes what canGrande Cone will be documented.
and cannot be seen on subsurface.
Location
Attribute Analysis
Rio de la Plata and Rio Grande Cone were formed
All information extracted from seismic data is known
during the Maastrichtian/Danian Atlantic transgres-
as Attribute and the interpretation depends on the
sion in South America. The continental shelf and the
combination of attributes, the quality of data, and the
depression are flooded by the sea. They are typical
interpreter’s experience. The Attribute is used to
examples of geoforms can be seen on the Uruguay
highlight subsurface features in order to delimit hori-
and Brazilian platforms. The Rio Grande Cone
zons, zones, seismic facies, and geometries by in-
(RGC) is a relevant geoform that extends 28900 km²
creasing the ability to define structural models and
on the Brazilian offshore (Figure 1). It is a subsurface
stratigraphic analysis. The advantage of seismic data
landscape semicircular-shaped noticeable feature
is the multiplicity, areal extension and depth penetra-
that comprises a transition from shelf to slopes with a
tion as it permits obtaining information from seismic
high amount of shale supply. Its source is the high-
attributes (Taner et al. 1977, 1979). Seismic attrib-
lands and the Brazilian craton.
utes are calculated from at least two trace input and
provide information about lateral variations in set
data. An Attribute is not restricted to structural orSeismic Data
stratigraphic analysis; it has been used to estimate
In this analysis, the data corresponds to 3577km of petrophysic properties and geomorphological ele-
seismic lines that were acquired from Brazil’s ANP, ments by combining them with well data. Historical
and other old printed sections (Fontana, 1996; Porto, development of seismic tools and techniques im-
2007). Structural and straigraphy models were gener- prove the execution of the different stages of
ated by means of software modules: Petrel 2008, seismostratigraphic analysis. Seismic stratigraphy
Matlab (v. 7.0.1), Voxler, Seismic Unix and open and attribute analysis could be considered as tools for
source seismic interpretation software (OpendTect geomorphological, geological and geophysical mod-
V3.03e). eling (Figure 2).
The dominant frequency seismic information
could be obtained from attributes analyses, i.e. an in- Seismic attributes application
stantaneous frequency map, which exhibits a were introduced in the seventy’s30-35Hz dominant frequency and 90 µs/ft slowness
first to display seismic data, then to obtain differentin the area. A 4ms sample rate, 5 to 10s record length
derived seismic measures, and finally turned into anand 28ms windows time analyses are comprised. In
analytical tool to predict lithological characteriza-
order to establish the wavelength, geophysical pa-
tion.
rameters on Pelotas Basin whose average velocity is
3050 m/s and frequency of 30Hz need to be consid- Although a direct relationship between the at-
ered. The expression for wavelength is given by: tributes and the geological characteristics of the
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RIO GRANDE CONE TECTONO-STRATIGRAPHIC MODEL – BRAZIL: SEISMIC SEQUENCES
TimeAdquisition Processing Interpretation
line
CMP Configuration
1D
1960 Synthetic Seismogram
Air Gun Marine
Digital Recording Digital Seismic Processing
Bright Spot Technology
Workstation
Digital migration
Comercial Seismic Attribute Comercial in colors2D
1970
Color Display
Introduction to3Dshot
Vertical Seismic Seismic Attribute concept
profile (Anstey) Complex Traces Analyses
Energetic Crises Trace Complex
Seismic Stratigraphy
Dip Moveout Geophysicist
2.5 D Seismic Inversion AnalysesStratigraphy
Horint Attributes
19803D Dip, zimur
AVO analysis 3D autotracking
Attribute proliferation Attributes respose
3D Seismic (Brown)Seismic Attributes
expansionOcean deep Cable Seismic Stratigraphy Sequences
Subsalt Imgen
1990
Seismic Attributes Attribute analysis
Analysis Classification4D
Coerence Attribute
Introduction
Texture Attributes
Spectral decomposition
Neural network
Analysis of Multi-Attributes Geomorfología Sísmica2000
Volumentric AttributesAttributes and Horizons
Classes
Spectral Inversion
Now
Figure 2. Historical development of the seismic method: acquisition, processing, interpretation and modeling (Adapted
from Liner, 2008; Chopra and Marfurt, 2005 and Friedman, 1998).
Earth has not been established, almost all analyses toric approaches of seismic stratigraphy, sequential
describe several uses of seismic attributes i.e. stratigraphy, fluvial geomorphology and three di-
classes’ classification discriminator. mensional modeling. Seismic attributes are used in
structural, stratigraphy and geomorphologycal inter-
Recently, the seismic attribute application in-
pretation (Figure 3). An example of this is the im-
cludes surfaces, horizon, geomorphology mapping,
provement of image resolution thanks to the
sequence stratigraphic interpretation, modeling
sophistication of computational systems that allow
subsurface and geobody information. They all have
determining reservoir properties and their lateral
been accepted as tools to interpret old strata and pro-
continuity. Figure 3. Dip seismic line display of Seis-
cesses through the use of modern survey
mic Attribute analysis and seismic stratigraphy inter-
(Posamentier and Kolla, 2003). Then seismic geo-
pretation
morphology is an evolving field, building on the his-
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CASTILLO., L.L.A, KAZMIERCZAK, T. DE S., AND CHEMALE., JR., F.
Structural Seismic Attributes Stratigraphic
Sequencial Stratigraphy
Interpretation
RMS windows 9Local Flat
Dip seismic line
RMS windows 3Acoustic Impedance
Schematic Sequence
SmoothIsofrequence
Figure 3. Dip seismic line display of Seismic Attribute analysis and seismic stratigraphy interpretation
In the seismic images processing, local seismic faults and channels (Marfurt et al. 1998). This crite-
attributes analyses (LSAA) are being used to measure rion guides the interpreter in the establishment of
seismic signal characteristics of neighboring points. seismic reflection attributes and seismic facies pat-
This technique has been applied in different steps of terns. Instantaneous amplitude and frequency, which
multicomponent seismic image acquisition (Fomel, are the most frequently used, show changes in lateral
2007). In this paper Attributes were used to delineate continuous reflections.
structural (dip/azimute, ant-tracking, dip deviation,
Some attribute analyses were applied to seismic
local structural dip, structural smoothing, variance,
lines belonging to the Brazilian offshore. The most
etc), stratigraphy (iso-frequence component, local
important features are the lineaments and fractures
flatness, acoustic impedance, etc) and geomor-
found by means of local flat analyses and relative
phologic (gradient, coherence, strata slices attributes,
acoustic impedance that showed normal faults influ-
horizon slice attributes etc) features (Figures 2 and
encing the sedimentary package into the Rio Grande
3).Coherence attribute measures the similarity of a
Cone. Root meters square permits delineating strong
trace with its neighbors and display discontinuities,
reflectors that could be correlated and interpreted by
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RIO GRANDE CONE TECTONO-STRATIGRAPHIC MODEL – BRAZIL: SEISMIC SEQUENCES
a sequence stratigraphic model, and delineated by adiastrophic tectonic developed, influencing basal
geomorphological elements like channels. sequences, i.e., the Aptian-Albian sequence. Above
it more than 3000 m of sediments belonging to Rio
Grande Cone were laid (Fontana, 1996). Structural
Seismostratigraphy and sequence sequences are influenced by tectonic and sedimen-
stratigraphy of the Rio Grande Cone tary structures. Relevant structures correspond to ac-
tive system faults until Pleistocene -late Wisconsin
Rio Grande Cone is located in a passive margin basin
(Alves, 1977).
characterized by several progradational systems sup-
plied by fluvial and cratonic sediments influenced by From a structural point of view, fault systems are
sea level fluctuations. Some geological features have the most relevant factor that affects clastic sequences.
been reported by authors like Alves (1977); Fontana The first domain contains a faults system, including
(1996) and Porto (2007). listric faults, thrust and their detachment planes.
Those structures are characterized by normal faults
Seismic section and attributes permit identifying
that were originated by distensive stress generating
structural, sedimentology, and geomorphology fea-
displaced blocks located on the proximal area
tures and they allow determining structural and the
(Northeast-Southwest trends and vergence to the
stratigraphic sequences elements.
Northwest). There are some small faults on the
cone’s distal section which structural style changes to
Tectonic structures description inverse faults. This style is located to the end of the
section (Figure 4).The southeast of the Brazilian offshore is composed
by sequences influenced by rift faults causing a Some seismic section permit identifying gravita-
half-graben configuration on the basal sequence. The tional deposits associated to fault systems, generating
Rio Grande Cone comprises pos-rift sequences. The deformational and tectonic structures. Studies have
Post-rift stage starts during Aptian, in which the
Figure 4. Three-dimensional structural model of the Rio Grande Cone, Brazilian Southeast.
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CASTILLO., L.L.A, KAZMIERCZAK, T. DE S., AND CHEMALE., JR., F.
determined that some lineaments and faults were method revealed along to Rio Grande do Sul and the
originated by fluids decompactation, and have influ- Uruguay’s continental margin a 1.8 km/s wedge, and
enced on the generation of fluid escape structures a velocity model for the sedimentary sequence
visible on the sea bottom’s surface (Fontana, 1996; (Alves, 1977). The wedge sedimentation lasted from
Middle Miocene to Pleistocene. Stages of depositionPorto, 2007).
and erosion were caused by eustatic sea level fluctua-
The Rio Grande Cone constitutes a huge sedi-
tions, originating the development of four sedimen-
mentary package characterized by the result of chan-
tary sequences. The depocenters distribution
nel system morphology, sediment waves and
suggests a source migration towards the continent,
contourities that have been influenced on the upper
maybe due to marine transgression (Alves, 1977). A
sequences by a distensional fault system that origi-
different interpretation for the Pelotas Basin and
nated normal faults to the North and inverse faults to Florianopolis shelf established eight sedimentary se-
the South. quences using seismic reflection (Gonçalves et al.
1979). Martins (1983) described the Rio Grande
Cone as a sedimentary-originated deep sea featureStratigraphic Sequence
supplied by Rio Grande do Sul highlands, within the Rio Grande Cone
progradational deposition and gravitational pro-
The seismic stratigraphic interpretation of the Pelotas
cesses (turbidities and another flux) modeled by bot-
Basin includes at least sixteen sequences (Butler,
tom current. Some researchs reports hydrate gas in
1970; Fontana, 1996 and Porto, 2007). The cone’s
the Pelotas Basin, i.e., Fontana (1989), Rosa et al.
area has geoforms, internal structures and velocity
(2006).
models that can be described with geophysical meth-
ods, for instance seismic refraction. The refraction
Figure 5. Seismic dip line (DI) interpretation of surface (SU: unconformity; MRS: Maximum Regressive and MFS: Maximum
flooding surfaces) sequences (HNR: High normal Regressive, LNR: Lowstand Normal Regressive ).
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The generated Trasgressive (T), highstand post-rift (drift) sequences. The middle and upper se-
(HNR) and Lowstand regressive (LNR) could be iden- quences belong to the Rio Grande Cone (Figures 5
tified on seismic sections (Figure 5). The shelf edge and 6). The Middle sequences correspond to onlap
suffered erosion resulting in the truncation of the transgressive sequences and downlap basinward. All
prograding sediments. The eroded sediments fed it sequences permit identifying montiforms with
via suspension or gravitational processes. This feed- bidirectional downlaps that represent the lowstand
ing was four times greater than Holocene rates. fan unit deposited on the basin’s deeper area. This is
the first lowstand stage in which a rapid decrease on
eustatic curve inflection occurs. Few continuous re-Seismo-stratigraphy and sequence
flections and variable amplitudes are found onstratigraphy description
paleoslopes. Middle sequences with erosion surfaces
In order to describe the evolution of the Rio Grande changed from Cretaceous to Tertiary. Geological
Cone, it is important to describe its tectono-stratigra- mapping considerations comprise sequences that
phy. The Cone comprises several Continental and have been influenced by different structural and
Figure 6. Sea level variations (Haq et al, 1987) and cronostratigraphy interpretation correlation in the Rio Grande Cone
(Alves, 1977; Fontana, 1996; Porto, 2007 and this paper).
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CASTILLO., L.L.A, KAZMIERCZAK, T. DE S., AND CHEMALE., JR., F.
stratigraphic styles dominated by facies variations Due to the instability of the upper sequences
that were caused by a high quantity of sediments sup- originated by steep slopes, the seismic has estab-
lished slumps geometric characteristics that lead to aply. The upper sequences that belong to the Rio
progradational system. The sediment supply in a de-Grande Cone are characterized by changes from
cline plane influenced by a higher sea level producesretrogradational to progradational sequences. Trans-
a mass flow deposit.gressive (T) and regressive features (LNR) are the re-
sult of sea level fluctuations that occurred from The highstand (HNR) is constant from Paleocene to
Aptian. In the Holocene Transgression (T), the Middle Eocene and Oligocene, through regressive in-
southeast continental margin has not received any termittent cycles that finished with an Oligocene regres-
significant quantity of terrigenous supply. Two pro- sion (This is shown by hard layering, as result of
cesses are still active: widespread pelagic and sedi- paleoshelf). There are regional Terraces and an erosive
mentation geostrophic. Contour current activity surface covered by deltaic events until Upper Pleisto-
developed along lower continental rise. Bottom-cur- cene on RiodelaPlata, (Martins, 1983; Martins etal.
rents deposits result from upslope flowing processes, 1990). They have similar geometries to the Rio Grande
while gravity deposits result from downslope pro- Cone. Sedimentary effects in the Paleocene cycles
cess. Recent drift sequences allow identifying slope could be evident in quiescence tectonic causing stabil-
features deposited by bottom-currents, slump and ity. In the final cycle, as result of Andean tectonics, a
gravity deposits process (Alves, 1977). Regional tilt from West South American took place and
Figure 7. 3D Model obtained from seismic stratigraphic interpretation showing paleoshelf and several stratigraphic se-
quences and highlights the tectono stratigraphic features of the Rio Grande Cone.
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RIO GRANDE CONE TECTONO-STRATIGRAPHIC MODEL – BRAZIL: SEISMIC SEQUENCES
caused the beginning of the sea level decrease and the to eustatic episodes with sea level changes that are
deposition of progradantional sequences. This event controlled by Andean orogenic pulses.
could be coincident with Haq curve (Figure 6).
ConclusionThe feature named Rio Grande Cone
could be defined as a huge semicircular shape geo-Rio Grande Modeling and MappingThe bound-
logical body with a thick package of sediments. It isaries and horizon picking obtained in 2,5-D configu-
mainly a shale geoform. The area is influenced byration permitted constructing the three-dimensional
complex structures that affect the whole sedimentarysubsurface image of the Rio Grande geoform (Figure
package. The Rio Grande Cone is overlying an older7). Seismic stratigraphic analyses and basal sequence
inferior and a middle sedimentary sequence that con-mapping permit identifying platforms with regres-
stitute the Pelotas Basin sequences. The cone com-sive progradational sediments. The sequences are
prises the basin’s younger sequence which is thecomprised by sequential systems in a marginal sag
upper sequence.The three dimensional analysis com-type since late Cretaceous. These correspond to the
prises an academic research of seismic data appliedPelotas Basin sequences.
to the modeling and visualization for interactive un-
The semicircular-shaped plan-view morphology derstanding. This will permit a paleogeomorpholgy
extends to the Southeast and strike to the North. The reconstruction of Rio Grande Cone.
thick recent sequences are crossed by faults systems
A methodology and a typical sequence of seis-
and by the presence of geophysics anomalies, for in-
mic interpretation are given in this paper. The pur-
stance a reflector that simulates the bottom surface
pose is to show the importance of visualization,
(BSR). This reflector is an anomaly generated by the
attribute analysis and modeling, especially in sequen-
high impedances caused by hydrate gas presence.
tial stratigraphy.
Below 500 ms, a system faults extends cutting all up-
per sequences. It is important to emphasize the use of different
computational technologies as tools for data interpre-
Near offset or proximal sector it includes some
tation, visualization, and the recovery of information
clinoform set which has been separated by internal
for the subsurface image by means of a velocity
downlap surfaces and are not faulted. Visualization
model.
and 3D modeling has allowed defining fault systems
geometries (Figure 7), showing details of normal
faults. This process includes fault propagation and Acknowledgments
could be interpreted as a polygonal faults system
This article was written for the Doctorate Program
due to contraction factors and early fluid expulsion
Research in the Federal University of Rio Grande do
during possible burial, where compaction acts in
Sul (UFRGS - Porto Alegre, Brazil) sponsored by Na-
different directions on clay rich sediments.The Rio
tional University of Colombia. Thanks to National
Grande Cone progradational layering produce con-
Petroleum Agency for providing some of the seismic
tinuous offlap, evidencing features like the conti-
lines used in this paper. Thanks to Schlumberger for
nental slope, the Marginal Cone, Progradational
the software contribution, especially to the technical
systems, and the upper interval that constitute recent
support for Petrel’s (Module and tools 2008), pro-
continental Shelf (Urien et al. 2003). The last stage
cessing, visualization and seismic interpretation with
during the inferior Holocene sedimentary disper-
the geophysical integration data.
sion included erosive process through submarine
sedimentation.
References
Eustatic changes are less evident during the Neo-
gene. The Highstand and Lowstand alternation could Al-Husseini, M., Glover J. and Barley B. (1981).
be aged Miocene and Pliocene. They are associated Dispersion Patterns of the Ground Roll in East-
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