PhD Thesis about the Garzan Carbonates and their log charecters, microfaices and sequence stratigraphy. Garzan Oil field and its log to micrfacies correlations.

1. Z.E.YILDIZEL
June, 2008
DEPOSITIONAL STACKING PATTERNS AND CYCLES OF
GARZAN FORMATION IN THE GARZAN-GERMİK OIL
FIELD: AN APPROACH TO CYCLE TO LOG CORRELATION
BY
ZEYNEP ELİF GAZİULUSOY YILDIZEL
June 2008

2. Z.E.YILDIZEL
June, 2008
Outline of the Presentation
1. Introduction (8 slides)
– The methodology
– The location and general geology of the study area
– General acceptances about GR and SONIC logs
1. Microfacies, cycles types, depositional environment
and stacking patterns of the Garzan Formation (10
slides)
2. An example to some of the studied wells (3 slides)
3. Cycle to log correlation (4 slides)
4. Discussions and conclusions (3 slides)

3. Z.E.YILDIZEL
June, 2008
Acknowledgements
• Prof. Dr. Demir Altıner
• Mr. Mehmet Sünnetçioğlu, Mrs. Ekmel Uygur,
• TPAO management, A. Faruk Öner (24th
October 2003 GM authorization)
• My Family
• Dr. Ali Yıldızel
• Miss. Zeynep Ezgi Yıldızel. She gives meaning to my life being my daugther

4. Z.E.YILDIZEL
June, 2008
Purpose Of The Study
• To find a direct correlation with the cycles?, facies?,
stacking patterns? with the logs of the Garzan Formation
• To achieve this purpose;
– Microfacies of the Garzan Formation are described by using
Dunham (1962)
– Depositional environment is comprehended
– Cycle types are defined from microfacies and the stacking
patterns of the Garzan Formation is outlined
– Log correlation with the cycles and stacking patterns is
interpreted
1. Introduction

5. Z.E.YILDIZEL
June, 2008
Geographical Setting and Historical Precedence of the
Garzan-Germik Oil Field
• 45km west of Siirt and 120km east of Diyarbakır town
• Fields are on surface anticline trending NW-SE
• 1944-1989 107 wells on Garzan field (73 oil well)
• 1957-1988 23 wells on Germik field (2 oil well)
• MTA discovered the field in 1950 by Garzan-2
• Second field discovered in Türkiye after Raman
• Avarage porosity is 10% and permeability is 10md in Garzan field
• Avarage porosity is 15% and permeability is 10md in Germik field.
• Thickness 190m in Garzan field.
• Thickness 150m in Germik field.
• 45810823 bbl (April 2008)
• Garzan field oils 26.4o
API
• Germik field oils 19o
API
1. Introduction
GARZAN FIELD
14
73
6
2
5
7
0
10
20
30
40
50
60
70
DRY WELL OIL WELL DRY WELL
with OIL
SHOW
ABANDONED
FOR
TECHNICAL
WATER WELL INJECTION
WELL
GERMİK FILED
3
2
0
10
7
0
0
2
4
6
8
10
DRY WELL OIL WELL DRY WELL
with OIL
SHOW
ABANDONED
FOR
TECHNICAL
WATER WELL INJECTION
WELL

6. Z.E.YILDIZEL
June, 2008
Geological Map of the Study Area
• Hoya Fm. (Middle-Upper Eocene) exposed on the crest
• Germik (U. Eocene-Oligocene) and Şelmo (Miocene)
outcrop along the flanks
• General trend is NW-SE
1. Introduction
Garzan-Germik Oil Fİeld
B. Raman Raman
Kentalan
Softek
Hazro

7. Z.E.YILDIZEL
June, 2008
Major Structures of Southeast Anatolia
modified from Perinçek et. al., 1987)
1. Introduction

8. Z.E.YILDIZEL
June, 2008
Top Garzan Formation
•Top Garzan map
•Highest subsurface
elevation is at
Garzan- 23 well
•The lowest
subsurface
elevation is at
Germik-3 well
1. Introduction

9. Z.E.YILDIZEL
June, 2008
Geology and Stratigraphy of Garzan Formation
• Garzan Formation is firstly defined as Kıradağ reef
limestone by Schmidt in 1961 and named as Garzan Reef
limestone by Kellog in 1961 under the subsurface.
• Maastrichtian in age
• Subtidal to open marine carbonate
1. Introduction

10. Z.E.YILDIZEL
June, 2008
Base Map of the Study
1. Introduction

11. Z.E.YILDIZEL
June, 2008
Basic Terminology SONIC and GR logs
• The sonic log provides a formations interval
transit time which is the reciprocal of the
velocity. (1/v) (msec/feet).
• the sonic log is sensitive to subtle textural
variations and it can help to identify the
lithology.
• Sonic log is used for correlation because of its
distinctive characteristic.
• The radioactivity of the rock measured by GR
log tool is generally a direct function of the clay
mineral content and this grain size and
depositional environment.
• Gamma ray logs are often used to infer changes
in depositional energy, with increasing
radioactivity reflecting increasing clay content
with decreasing depositional energy.
• The GR log can be used to correlate and to
suggest facies and sequences and to identify
lithology.
• Carbonates in their pure state are not
radioactive and this aids their identification.
However, carbonates contain organic matter
and this is frequently radioactive due to
uranium.
• Shapes on gamma ray log can be interpreted as
grain size trends and by sedimentological
association as facies succession
1. Introduction
The correlation of log shape with
grain size trend is tenable only
under very limited conditions. A
universal application of gamma
ray log shape to grain size trend
and depositional facies is wrong
(Rider, 1990)

12. Z.E.YILDIZEL
June, 2008
Microfacies Types Of The Garzan Formation
• Miliolid Wackestone
• Rotalid Miliolid Wackestone
• Orbitoid Miliolid Wackestone
• Pelagic Foraminiferal Mudstone
• Rudist Wackestone
2. Microfacies
• subtidal, backshoal, shoal, foreshoal and open marine environment are present.
• The supratidal, intertidal and slope facies are not present in this study.

13. Z.E.YILDIZEL
June, 2008
Miliolid Wackestone Subtidal Environment
• miliolids 1%-20%,
• cuneolins 2%,
• other benthic foraminifers 1%-4%,
• matrix 60%-80%,
• orbitoids 1% as fragments,
• algs 1%-3%,
• pelecypods and gastropods 1%-5%,
• echinoid fragments 1%-6%,
• rotalids 1%-3%,
• osracodes 1%-4%
2. Microfacies
Miliolid Wackestone
0.43 0.93 0
6.48
3.95
0
2.4 1.48 0.55 1.04 0
2.08
78.73
1.93
0
10
20
30
40
50
60
70
80
O
R
B
IT
O
D
E
S
A
LG
R
U
D
IS
T
FR
A
G
M
E
N
T
S
M
ILIO
L
ID
A
E
U
N
D
IF
FE
R
E
N
T
IA
T
E
D
C
O
R
A
L
FR
A
G
M
E
N
T
S
E
C
H
IN
O
ID
FR
A
G
M
E
N
T
S
P
E
LE
C
Y
P
O
D
A
+G
A
ST
R
O
P
O
D
A
C
U
N
E
O
LIN
A
R
O
T
A
L
ID
A
E
P
E
LA
G
IC
F
O
R
A
M
IN
IFE
R
A
O
T
H
E
R
B
E
N
T
H
IC
FO
R
A
M
IN
IFE
R
A
M
A
T
R
IX
O
S
T
R
A
C
O
D
A
avarage%
m
d?
avarage
Germik-21 well (X4, core) (m:miliolid, d:disyclina?)

14. Z.E.YILDIZEL
June, 2008
Rotalid Miliolid Wackestone Shoal to Foreshoal
• rudist fragments (2%-4%),
• miliolids (1%-20%),
• algs (1%),
• coral fragments (2%),
• echnoid fragments (1%-3%),
• pelecypods and gastropods (1%-6%),
• cuneolins (1%),
• rotalids (12%-40%),
• other benthic foraminifers (2%-5%),
• matrix (40%-70)
• ostracode (1%-5)
2. Microfacies
Rotalid-Miliolid Wackestone
0.01 0.49 0.87
10.23
0 0.52 1.61 2.04
0.46
20.54
0
2.38
57.94
2.91
0
10
20
30
40
50
60
O
R
B
IT
O
D
E
S
A
LG
R
U
D
IS
T
FR
A
G
M
EN
T
S
M
ILIO
LID
A
E
U
N
D
IF
FE
R
E
N
T
IA
T
E
D
C
O
R
A
L
FR
A
G
M
E
N
T
S
E
C
H
IN
O
ID
FR
A
G
M
E
N
T
S
P
E
LE
C
Y
P
O
D
A
+G
A
ST
R
O
P
O
D
A
C
U
N
E
O
LIN
A
R
O
T
A
L
ID
A
E
PE
LA
G
IC
F
O
R
A
M
IN
IFE
R
A
O
T
H
E
R
B
EN
T
H
IC
FO
R
A
M
IN
IFE
R
A
M
A
T
R
IX
O
S
T
R
A
C
O
D
A
avarage%
avarage
G. Germik-1 well (X4, cutting), (o: orbitoid, ro: rotalid, r:rudist).
o
ro
ro
r

15. Z.E.YILDIZEL
June, 2008
Orbitoid Miliolid Wackestone Backshoal to Shoal
• orbitoides (2%-24%),
• rudist fragments (20%-36%),
• echinoid fragments (2%-30%),
• rotalids (2%-16%),
• matrix (20%-70%),
• miliolids (%-11%),
• algs (1%),
• coral fragments (2%-7%),
• pelecypods and gastropods (2%-11%),
• cuneolins (1%),
• other benthic foraminifers (2%-10%),
• ostracodes (2%-6%)
• pelagic foraminifers are absent
Orbitoid-Miliolid Wackestone
11.30
0.61
9.41
2.06
0.00
1.41
8.86
2.99
0.08
8.30
0.00
2.35
50.43
2.20
0
10
20
30
40
50
60
O
RB
ITO
DE
S
ALGRU
D
IST
FRAG
M
EN
TS
M
ILIO
LID
A
EU
N
DIFFEREN
TIATEDCO
R
AL
FRA
G
M
EN
TS
ECH
IN
O
ID
FRAG
M
EN
TS
PELECY
PO
D
A+G
A
STRO
PO
DA
CU
N
EO
LIN
A
RO
TALIDA
E
PELA
G
IC
FO
RAM
IN
IFERA
O
TH
ER
BEN
TH
IC
FO
R
AM
IN
IFER
A
M
A
TR
IX
O
STR
ACO
D
A
avarage%
2. Microfacies
avarage
o
r
Garzan-31 well (X4, core), (o:orbitoid, r:rudist).

16. Z.E.YILDIZEL
June, 2008
Pelagic Foraminiferal Mudstone Foreshoal to Open Marine
• pelagic foraminifera (6%-20%)
• matrix (70%-90%)
• orbitoids (1%-7%),
• other benthic foraminifera
• pelecypods and gastropods (1%),
• ostracodes (5%)
Pelagic Foraminiferal Mudstone
1.90
0.00 0.00 0.00 0.00 0.00 0.00 0.02 0.00 0.00
14.77
0.33
81.00
1.98
0
10
20
30
40
50
60
70
80
90
O
R
B
IT
O
D
E
S
A
LG
R
U
D
IS
T
FR
A
G
M
E
N
T
S
M
ILIO
L
ID
A
E
U
N
D
IF
FE
R
E
N
T
IA
T
E
D
C
O
R
A
L
FR
A
G
M
E
N
T
S
E
C
H
IN
O
ID
FR
A
G
M
E
N
T
S
P
E
LE
C
Y
P
O
D
A
+G
A
ST
R
O
P
O
D
A
C
U
N
E
O
LIN
A
R
O
T
A
L
ID
A
E
P
E
LA
G
IC
F
O
R
A
M
IN
IFE
R
A
O
T
H
E
R
B
E
N
T
H
IC
FO
R
A
M
IN
IFE
R
A
M
A
T
R
IX
O
S
T
R
A
C
O
D
A
avarage%
Garzan-23 well (X10, cutting), (p: planktonic foraminifera).
2. Microfacies
avarage

17. Z.E.YILDIZEL
June, 2008
Rudist Wackestone Backshoal to Shoal
• rudist fragments (3%-54%),
• echinoid fragments (3%-15%),
• pelecypods and gastropods (1%-9%)
• matrix (30%-90%)
• orbitoids and ostracodes (1%),
• miliolids (1%-4%),
• coral fragments (2%),
• rotalids (1%)
• other benthic foraminifera (3%-23%)
Rudist Wackestone
0.76 0.00
27.89
0.81 0.00 0.53
7.44
4.94
0.00 0.32 0.00
6.23
50.90
0.17
0
10
20
30
40
50
60
O
R
B
IT
O
D
E
S
A
LG
R
U
D
IS
T
FR
A
G
M
E
N
T
S
M
ILIO
L
ID
A
E
U
N
D
IF
FE
R
E
N
T
IA
T
E
D
C
O
R
A
L
FR
A
G
M
E
N
T
S
E
C
H
IN
O
ID
FR
A
G
M
E
N
T
S
P
E
LE
C
Y
P
O
D
A
+G
A
ST
R
O
P
O
D
A
C
U
N
E
O
LIN
AR
O
T
A
L
ID
A
E
P
E
LA
G
IC
F
O
R
A
M
IN
IFE
R
A
O
T
H
E
R
B
E
N
T
H
IC
FO
R
A
M
IN
IFE
R
A
M
A
T
R
IXO
S
T
R
A
C
O
D
A
avarage%
Garzan-95 well (X4, core), (r:rudist, b:bryozoan?)
2. Microfacies
avarage

18. Z.E.YILDIZEL
June, 2008
Cycle Types Of Garzan Formation
2. Cycles
• Type A
• Type B
• Type C
• Type D
• Type E

19. Z.E.YILDIZEL
June, 2008
Cycle Stacking in the Garzan Formation
2. Cycles

20. Z.E.YILDIZEL
June, 2008
Stacking Patterns and Their GR lgos
2. Stacking Patterns

21. Z.E.YILDIZEL
June, 2008
Depositonal Environment of the Garzan Formation
2. Depositional environment

22. Z.E.YILDIZEL
June, 2008
G.Germik-1
• Garzan fm (1957-
2091m)
• 134m Garzan thickness
• GR-SONIC
3. Wells

23. Z.E.YILDIZEL
June, 2008
Garzan-82
• Garzan fm (1553-1719m)
• 166m Garzan thickness
• SP-SONIC
3. Wells

24. Z.E.YILDIZEL
June, 2008
Garzan-23
• Garzan fm (1461-1524m)
• 63m Garzan thickness
• GR-Resistivity
3. Wells

25. Z.E.YILDIZEL
June, 2008
Generalized Log Patterns of the Garzan Formation
4. Cycle to Log

26. Z.E.YILDIZEL
June, 2008
GR log _Germik-21, G. Germik-1, G. Germik-2, Garzan-33, Garzan-31 and Garzan-23
• G.Germik-2 is not examined on the thin esction basis fo microfacies but the log
patterns and log to sysle stacking correlation made it possible to evaluate well and to
correlate it with the others.
• Also Garzan-31 and 33 has a limited amount of thin section but the log patterns made it
easy to be correlated with others.
4. Cycle to Log

27. Z.E.YILDIZEL
June, 2008
SONIC log _ Germik-21, G. Germik-1, G. Germik-2 and Garzan-82
4. Cycle to Log
?

28. Z.E.YILDIZEL
June, 2008
Germik-21 (GR), Garzan-33 (GR), Garzan-43 (Resistivity) and Garzan-82
4. Cycle to Log

29. Z.E.YILDIZEL
June, 2008
Results
•Type A and D cycles are retrogradational meaning net landward
movement of the facies. Meaning deepening in the cycle.
•They have to have an increasing trend in the GR so that the
relatively deeper facies overly relatively shallower facies.
•On the contrary they show decreasing tren in GR values.
•Type E cycle is progradational meaning net movement of facies
towards basin. It has to show a decreasing trend in GR readings
menaing that the shallower facies overly the deeper ones.
(decrease in clay content)
•On the contrary type E cycle has relatively increasing trend in GR.
5. Discussion and Conclusions
50o

30. Z.E.YILDIZEL
June, 2008
Results
•The deposition of the Garzan
Formation is a deepening upward
cycle and is deposited during the
major transgression of Maastrichtian .
•The stacking patterns of more deeper
faices on to shallower ones
represents the trangressive phase
and the other two high stand systems
tract are generally characterized by
aggradational type except type E
cycle.
•The cycles are capped by Miliolid
Wackestone facies (type A, B, C, and
E cycles) and Pelagic Foraminiferal
Mudstone facies (type D cycle)
because o f the rise on sea level is so
much that the carbonate production
could not keep up and grade into
more clay rich facies.
•subtidal environment enlarges
because of rapidly rising sea level.
This leads to the domination of muddy
cycles in the environment.
•At the top of the Garzan Formation
deposition the rapid rising reached to
a maximum level that the open marine
conditions start to dominate the
deposition
5. Discussion and Conclusions

31. Z.E.YILDIZEL
June, 2008
Conclusions
• Orbitoid Miliolid Wackestone and Rudist Wackestone of back shoal to shoal , Miliolid Wackestone facies
of subtidal, Rotalid Miliolid Wackestone of shoal to fore shoal and Pelagic Foraminiferal Mudstone of fore
shoal to open marine environment.
• type A cycle (retrogradational) deposited during transgressive systems tract, type B cycle (aggradational)
deposited during high stand systems tract, type C cycle (aggradational) deposited during high stand
systems tract, type D cycle (retrogradational) deposited during the upper transgressive systems tract,
type E cycle (progradational) deposited during high stand systems tract deposition. there is also the
maximum flooding surface located usually at the top of type D cycle .
• The base Garzan starts with type E and C cycles. Then type A cycle overlies type C cycle and this onset is
represented by type 2 sequence boundary. Over type A cycle there is an alternation of type B and C cycles
and this part of the deposition is an aggradational type of deposition. The top Garzan is defined by type D
cycle and maximum flooding surface ends up the Garzan Formation deposition. Below the type D cycle
there is the second type 2 sequence boundary.
• The maximum flooding surfaces are located towards the top of the wells at the onset of Alt Germav
deposition.
• The overall Garzan Formation deposition is transgressive and the formation shows deepening upward
trend which is deposited during the major transgression of Maastrichtian.
• The standard GR interpretation is not applicable in most of the carbonates and in Garzan Formation in
Garzan-Germik oil field. In Garzan deposition a decrease in GR readings indicates a decrease in energy
and relatively deepening with domination of deeper facies.. Besides an increase in GR readings indicate
an increase in energy and the domination of shallow water facies. In carbonate depositional environments
when GR reading increases in API this should not be interpreted as trangressive cycles without any
facies control.
• The Garzan Formation in Garzan- Germik oil field can be interpreted on the basis of cycles and system
tracts without any microfacies control by using the generalized log patterns. This correlation can be
carried out whole through the field.
5. Discussion and Conclusions

32. Z.E.YILDIZEL
June, 2008
DEPOSITIONAL STACKING PATTERNS AND CYCLES OF
GARZAN FORMATION IN THE GARZAN-GERMİK OIL
FIELD: AN APPROACH TO CYCLE TO LOG CORRELATION
BY
ZEYNEP ELİF GAZİULUSOY YILDIZEL
June 2008