architectural elements and facies distribution along an actively growing deepwater basin margin ...

240 Pages·2013·13.23 MB·English

ARCHITECTURAL ELEMENTS AND FACIES DISTRIBUTION
ALONG AN ACTIVELY GROWING DEEPWATER BASIN
MARGIN, EOCENE MORILLO STRATIGRAPHIC UNIT, AINSA
BASIN, SPAIN

By
Prianto Setiawan
A thesis submitted to the Faculty and the Board of Trustees of the Colorado School of
Mines in partial fulfillment of the requirements for the degree of Master of Science
(Geology).

Golden, Colorado
Date _____________

Signed: ____________________________
Prianto Setiawan

Signed: ____________________________
Dr. Renaud Bouroullec
Thesis Advisor

Signed: ____________________________
Dr. David R. Pyles
Thesis Advisor

Golden, Colorado
Date _____________
Signed: ___________________________
Dr. John D. Humphrey
Associate Professor and Head
Department of Geology and Geological Engineering
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ABSTRACT

Deepwater depositional systems associated with actively growing basins are
important targets for hydrocarbon exploration and production. Seismic data of deepwater
basin-fills often reveal the occurrence of low amplitude/chaotic non-reservoir seismic
facies located close to basin margins. These strata separate the basin margins from high
amplitude/good continuity reservoir facies located in the axis of the basins. Outcrop
studies often focus on the nature of reservoir facies in the axial part of the basin, but little
is known about sedimentological and stratigraphic characteristics of basin margin strata.
The Eocene Morillo stratigraphic unit in the Ainsa Basin, Spain, is an outcrop
analog for sediment deposited within an actively growing deepwater basin margin. The
Morillo consists of siliciclastic-dominated strata located at the basin axis and carbonate-
dominated strata located at the basin margin. In this study, the Morillo is subdivided into
three condensed section bounding units called Morillo 1, Morillo 2, and Morillo 3. The
correlation method used allows a chronostratigrapic correlation between the siliciclastic-
dominated strata located at the basin axis and the carbonate-dominated strata located
along the basin margin.
The aims of this study are to: 1) better understand the evolution of the Morillo
stratigraphic unit through time, 2) develop a better understanding of sedimentological
characteristics (facies and architectural elements) of deepwater sediments along active
basin margins, and 3) quantify/measure the relationship that exists between basin margin
geometry, basin margin and basin axis strata. Data used in this study consist of measured
sections, paleocurrent data, photopanel interpretation, petrographic analysis, and mapping
of key-surfaces.
The Morillo stratigraphic unit is bounded by actively growing structures which
are the Mediano Anticline to the east and Boltana Anticline to the west. Morillo deposits
are delivered through four main delivery systems: (1) an east siliciclastic-dominated
slope, (2) a southeast carbonate-dominated submarine canyon, (3) a southwest stable
carbonate platform, and (4) a west mass transport complexes (MTCs)-dominated
carbonate system. Twenty 0ne facies are identified and represent the entire spectrum of
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sediment gravity flow processes ranging from slides, slumps, debris flows to turbidity
currents. Six types of architectural elements (canyon, channel, levee, MTCs, sheets, and
lobes) are identified and mapped within the basin.
The Morillo stratigraphic unit is interpreted to be deposited during a transgressive
to highstand system tract. Both carbonate and siliciclastic systems are interpreted to
display characteristics of continuous sea level rise from the Morillo 1 to the Morillo 3
depositional time. This continued sea level rise is also complicated by the local tectonics
of the growing basin margin. The sedimentary record shows that the basin bounding
structures were active at different times during the Morillo deposition.
Cross sections built along the basin margins reveals relationships between basin
margin geometry and stratal characteristics. First, slides, slumps and debris flows are
empirically related to steep basin margins. Second, the angle of basin margin at the time
of deposition is related to the width of non-reservoir quality strata (basin margin wedge)
that physically separates the basin margin to reservoir strata in the basin axis (The steeper
the basin margin is, the narrower the basin margin wedge is). These results indicate that
there are geometrical relationships between basin margin geometry, architectural element
proportion, and distance between basin margins to the reservoir strata. The result can be
used to deduce and predict architectural element and facies in seismic data using angles
relationship that can be directly measured from seismic. It is possible to use the results of
this study in similar settings to reduce uncertainty in the determination of the minimum
distance between basin margin and reservoir facies, which in turn could optimize drilling
strategy along active basin margins.

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TABLE OF CONTENTS

ABSTRACT ........................................................................................................................ ii
LIST OF FIGURES ........................................................................................................... ix
LIST OF TABLES .............................................................................................................xv
ACKNOWLEDGMENTS ............................................................................................... xvi
CHAPTER 1 INTRODUCTION .........................................................................................1
1.1 Research Objectives .....................................................................................1
1.2 Study Area ...................................................................................................2
1.2.1. Location ...........................................................................................2
1.2.2. Regional Geologic Setting ...............................................................3
1.2.1.1. Tectonics and Basin Setting ................................................3
1.2.1.2. Stratigraphy .........................................................................5
1.3 Methods and Data ........................................................................................6

CHAPTER 2 LITERATURE REVIEW ............................................................................17
2.1 Deepwater Basin Margin ...........................................................................17
2.2 Sediment Gravity Flows ............................................................................19
2.2.1. Turbidity Current .............................................................................20
2.2.2. Debris Flows ....................................................................................21
2.2.3. Co-genetic Turbidite and Debrite ....................................................22
2.2.4. Mass Transport Complexes (Slumps and Slides) ............................24
2.2.5. Sediment Gravity Flows Facies Model ............................................26
2.3 Deepwater Carbonate Depositional System ...............................................28

CHAPTER 3 SEDIMENTOLOGY AND STRATIGRAPHY OF THE MORILLO
STRATIGRAPHIC UNITS ...............................................................................................45
3.1 Facies .........................................................................................................45
3.1.1 Background ....................................................................................45
3.1.2 Facies of the Morillo Stratigraphic Units .......................................45
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3.2 Architectural Elements ...............................................................................47
3.2.1 Background ....................................................................................47
3.2.2 Architectural Elements of the Morillo Stratigraphic Units ............48
3.2.2.1. Channel Element ...............................................................48
3.2.2.2. Sheet Element ...................................................................50
3.2.2.3. MTC Element....................................................................51
3.2.2.4. Lobe Element ....................................................................53
3.2.2.5. Canyon Element ................................................................54
3.2.2.6. Levee Element ..................................................................55
3. 3. Stratigraphic Cycles .......................................................................................56

CHAPTER 4 MORILLO STRATIGRAPHIC UNIT ........................................................69
4.1 Introduction ................................................................................................69
4.2 Morillo 1 Stratigraphic Unit.......................................................................70
4.2.1. Morillo 1 Siliciclastic-Dominated Domain ....................................70
4.2.1.1. Proximal Siliciclastic-Dominated Domain: Morillo
de Tou .............................................................................71
4.2.1.2. Distal Siliciclastic-Dominated Domain: Rio Ara and
Rio Sieste ........................................................................72
4.2.2. Morillo 1 Carbonate-Dominated Domain ......................................77
4.2.2.1. Morillo 1 Southeastern Carbonate-Dominated Domain ...77
4.2.2.2. Morillo 1 Western Carbonate-Dominated Domain ...........79
4.2.3. Summary of the Morillo 1 Stratigraphic Unit ............................... 82
4.3 Morillo 2 Stratigraphic Unit.......................................................................84
4.3.1. Introduction ....................................................................................84
4.3.2. Southeastern Area: Samitier to Caboplano Peninsula ...................85
4.3.3. Eastern Area: Coscojuelo de Sobrarbe to Morillo de Tou .............88
4.3.4. Southwest Area: Santa Maria de la Nuez to Castellazo .................91
4.3.5. West Central Area: Rio Ena and Morcat .......................................94
4.3.6. Northwestern Area: Rio Sieste and Rio Ara ..................................97
4.3.7. Summary of the Morillo 2 Stratigraphic Unit ..............................100
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4.4 Morillo 3 Stratigraphic Unit.....................................................................102
4.4.1. Introduction ..................................................................................102
4.4.2. Southeastern Area: Samitier to Morillo de Tou. ..........................102
4.4.3. Southwestern Area: Santa Maria de la Nuez to Castellazo..........105
4.4.4. Northwestern Area: Rio Ena to Rio Sieste area ...........................108
4.4.5. Summary of the Morillo 2 Stratigraphic Unit. ............................ 111
4.5. Summary of the Morillo Stratigraphic Unit .............................................112

CHAPTER 5 DISCUSSION ............................................................................................174
5.1 Basin Configuration During the Morillo Stratigraphic Unit Depositional
Time .........................................................................................................174
5.2 The Stratigraphic Evolution of the Morillo .............................................176
5.2.1. Paleogeography of the Morillo Stratigraphic Unit .......................176
5.2.1.1. Paleogeography of the Morillo 1 ....................................176
5.2.1.2. Paleogeography of the Morillo 2 ....................................178
5.2.1.3. Paleogeography of the Morillo 3 ....................................180
5.2.2. Sequence Stratigraphy of the Morillo Stratigraphic Unit ............181
5.2.2.1. Record of Sea Level Rise in the Basin Margin ...............181
5.2.2.2. Record of Sea Level Changes in the Basin Axis ............183
5.3. Architectural Element Distribution Along an Actively Growing Basin
Margin ......................................................................................................184
5.4. Basin Margin to Axis Relationship ..........................................................185
5.5. Application to Reservoir Characterization ...............................................187
5.5.1. Basin Scale ...................................................................................187
5.5.2. Reservoir Scale ...........................................................................189

CHAPTER 6 CONCLUSIONS .......................................................................................208
6.1. Conclusions ..............................................................................................208
6.1.1. The Evolution of the Morillo Stratigraphic Unit .........................208
6.1.2. Facies and Architectural Elements Along the Growing Basin
Margin ..........................................................................................211

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6.1.3. Axis to Margin Relationship ........................................................212
6.2. Future Research .......................................................................................213

REFERENCES CITED ....................................................................................................215

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LIST OF FIGURES

Figure 1.1. Seismic example of salt withdrawal minibasin in the Gulf of Mexico
showing axis to margin relationship ............................................................8

Figure 1.2. Geographic map of the study area ...............................................................9

Figure 1.3 Geometry of the Pyrenees orogen ..............................................................10

Figure 1.4. Geologic map of the eastern Pyreneean .....................................................10

Figure 1.5. Paleogeographic map of the south Pyreneean foreland basins ..................12

Figure 1.6. Cross section of the south Pyreneean foreland basins ...............................12

Figure 1.7. General geologic map of the Ainsa Basin ..................................................13

Figure 1.8. General stratigraphic column of the Ainsa Basin fills ...............................14

Figure 1.9. Simplified stratigraphic chart of the Ainsa Basin ......................................15

Figure 1.10. Cross section from the Ainsa to Jaca Basin ...............................................15

Figure 1.11. Data distribution map within of the study area ..........................................16

Figure 2.1. Cross section of the Gull Island Formation, Ireland ..................................30

Figure 2.2. Depositional model of ponded turbidite strata, Annot Sandstone,
France .........................................................................................................31

Figure 2.3. Main control parameters on deepwater basin margin ................................32

Figure 2.4. Four end members of sediment gravity flows ............................................33

Figure 2.5. The anatomy of turbidity current, showing head and body .......................34

Figure 2.6. Vertical velocity profile of turbidity current ..............................................35

Figure 2.7. Cross sectional view of debris flow, showing shear and plug ...................36

Figure 2.8. Genetic relationship between debris flow and turbidity current ................36

Figure 2.9. Classification of sediment gravity flows ....................................................37

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Figure 2.10. Slumps as an indicator to interpret paleoflow direction ............................37

Figure 2.11. Classic turbidite facies model ....................................................................38

Figure 2.12. Density flows facies model ........................................................................39

Figure 2.13. Turbidite facies and related processes .......................................................40

Figure 2.14. Flow dynamics concept of turbidity current ..............................................41

Figure 2.15. Comparison of turbidite facies model ........................................................42

Figure 2.16. Comparison of turbidite facies model ........................................................42

Figure 2.17. Carbonate classification scheme ................................................................43

Figure 2.18 Slope profile comparison between siliciclastic, T factory, and C
factory carbonate ramp ..............................................................................43

Figure 2.19. Standard facies belt of carbonate depositional system ............................. 44

Figure 2.20. Common modification standard facies model ...........................................44

Figure 3.1. Photographs of 21 facies observed within the Morillo stratigraphic unit ..60

Figure 3.2. Photomicrographs of carbonate pre-growth strata .....................................62

Figure 3.3. Photomicrographs of Type 2 sheet (F12 facies) ........................................63

Figure 3.4. Photomicrographs of F6, F14, and F20 facies ...........................................64

Figure 3.5. Map of the proportion between carbonate and siliciclastic strata
identified from the petrographic description ..............................................65

Figure 3.6. Architectural elements within the Morillo stratigraphic unit .....................66

Figure 3.7. Erosional and depositional channel geometries from Mutti and
Normark (1991) ........................................................................................ 67

Figure 3.8. Hierarchy of channel elements from Gardner and Borer (2000) .............. 67

Figure 3.9. Regional stratigraphic column of the Ainsa Basin ....................................68

Figure 4.1. Geologic map of the Morillo stratigraphic unit .......................................113

Figure 4.2. Panoramic view of the Morillo stratigraphic unit at Morillo de Tou .......114
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