Content uploaded by Muhamed Fakhri Omer
Author content
All content in this area was uploaded by Muhamed Fakhri Omer on Feb 22, 2024
Content may be subject to copyright.
Iraqi Geological Journal
Aswad et al,
2023, 56 (2B), 37-50
Iraqi Geological Journal
Journal homepage: https://www.igj-iraq.org
DOI: 10.46717/igj.56.2B.3ms-2023-8-12
37
Kurra Chine Formation: Evaluation of Source Rock, Based on Rock-Eval
Pyrolysis Analysis Integrated by Selected Wells and Outcrop Samples in
Iraq's Kurdistan Region
Mahdi K. Aswad*1, Srood F. Naqshabandi1 and Muhamed F. Omer1
1
Earth Sciences and Petroleum, College of Science, Salahaddin University- Erbil, Iraq
*
Correspondence: mahdi.aswad@su.edu.krd
Abstract
Received:
23 November 2022
The current research deal with evaluating the Late Triassic Kurra Chine Formation using the
Rock-Eval Pyrolysis technique in selected wells in Sarta-2 and Tawke-17 Oil fields, and the
Sirwan Valley outcrop, in Northern Iraq. A total of twenty-six samples were selected for this
study; nineteen cuttings samples from the wells and seven outcrop samples from Sirwan
Valley. The total organic carbon wt.% of the formation in Sarta oilfield samples ranges 0.43–
2.51, and in Tawke samples ranges between 0.13–1.52, and for Sirwan Valley ranges between
0.02–0.32. Based on the total organic carbon content the Kurra Chine Formation can be
considered as poor to very good source rock in the Sarta Oil field and poor to good in Tawke,
and poor to fair source rock in Sirwan samples. Generation Potential shows some potential to
generate good source potential, moderate source potential, and poor generation potential in
the Sarta well, Tawke well, and Sirwan Valley as Generation Potential ranges between 1.47–
8.55, 0.48–4.46 and 0.02-0.11, respectively. The values of S1 range between 0.57–4.13,
0.15–1.02 and 0.01–0.03 mg HC/g rock for Sarta, Tawke, and Sirwan Valley respectively.
Based on the S1 values the Kurra Chine Formation is considered fair to excellent, fair to good
and poor source rock in the Sarta, Tawke, and Sirwan respectively. The analyzed samples
show an immature level with Tmax ranges between 292-405 and immature to early mature
with Tmax between 425-439 and immature to postmature with Tmax values between 339–
597 for Sarta, Tawke, and Sirwan respectively. Tmax-HI plot shows Kerogen types (II-III,
III-IV), (II to III), and (III-IV) for Sarta, Tawke, and Sirwan Valley respectively .
Accepted:
18 March 2023
Published:
31 August 2023
Keywords:
Rock-Eval Pyrolysis; Tawke Oil field; Sarta Oil field; Sirwan Valley outcrop;
Kurra Chine Formation; Northern Iraq
1. Introduction
Triassic Carbonate formations in Iraq are more important due to their lithological and hydrocarbon
content. Kurra Chine Formation is considered a unique petroleum system that includes source,
reservoir, and cap rocks. Rock-Eval pyrolysis is a technique that is usually used because it takes a short
time, has small samples, and costs less. Peters and Casa (1994) proved that total organic carbon (TOC)
is the main tool to determine the amount of organic matter in the source rock samples.
Petroleum production (PI) and generation potential (GP) are changed based on organic matter types.
Different types of organic matter will give different hydrocarbon generation (Tissot and Welte, 1984;).
According to Petters and Cassa (1994) starting and ending of the oil window ranged from 435-470 C
Iraqi Geological Journal
Aswad et al.
2023, 56 (2B), 37-50
38
and between 0.1 to 0.4 for Maximum Temperature (Tmax) and PI respectively. The Production Index
(PI = S1/ [S1 + S2]) was used to estimate the level of the maturation of organic matter. It shows the ratio
of the hydrocarbon produced from rock samples to the ratio of the hydrocarbon produced from the
sample through rock eval Tyson (1995).
Sadooni (1995) studied the source rocks evaluation of the Upper Triassic (Kurra Chine Formation)
and mentioned that the Kurra Chine Formation consists of complex interfingering of limestone,
anhydrite, and dolomite with shale and lime mud affected by dolomitization. Kurra Chine’s depositional
environment is restricted shelves, shallow lagoons, and organic reefs in semi-buried shelf lagoons
(Sadooni, 1995).
Previous studies about Kurra Chine Formation discussed the Organic maturation, kerogen type,
fractures, microfacies, heterogeneity, and depositional environment of the Kurra Chine Formation.
organic maturation and Kerogen types described in northern Iraq by (Ameri et al., 2009). They found
type II and III, mature organic matter, and a lagoon depositional environment. Aqrawi et al. (2010)
described Kurra Chine Formation into four lithological units which include two evaporite and two
carbonate rocks. Awdal et al. (2016) studied the Kurra Chine Formation based on the outcrop samples
in northern Iraq and they found a high fracture on the dolomite rocks with secondary porosity. Edlibi et
al. (2019) studied the source rock of the Kurra Chine Formation and found thermally mature organic
matter. Lunn et al. (2020) divided the Kurra Chine Formation into three subdivisions that include Kurra
Chine A, B, and C which reflect the three greatest flooding surfaces. Al-Dolaimy et al. (2021) studied
the organic maturity of the Kurra Chine Formation based on cutting samples by Pr/Ph and they found a
mature to early mature organic matter. Al-Dolaimy et al. (2021) studied the pyrolysis of the Kurra Chine
Formation based on the cutting samples from three subsurface wells by Rock-Eval analysis and found
the low potential of hydrocarbon generation and immature to mature organic matter. Al Hamdani et al.
(2021) studied the microfacies of Kurra Chine and found different depositional environments. Balaky
et al. (2022) described shale as heterogeneous in the Kurra Chine Formation. In northern Iraq, subsurface
drilled wells reached the Kurra Chine Formation which can be found from Tawke field, Swaratika Field,
and Sarta Field. It shows limestone, dolomite, dolomitic limestone, shale, and gypsum.
This research is to fill the gap related to the hydrocarbon generation potential of the Kurra Chine
Formation. Recently, some international oil companies drilled and penetrated the Kurra Chine
Formation, which has a potential hydrocarbon (Fig. 1).
The main aim of this research is to identify the potential hydrocarbon and quality of the organic
matter in recently drilled wells of the Kurra Chine Formation which has not been studied before. The
result of this research will solve the uncertainty in the Kurra Chine Formation and will assist the
petroleum companies to understand the significance of the Kurra Chine Formation. This project is new
and important because it used samples from the surface and subsurface drilled well of the Kurra Chine
Formation in northern Iraq.
Iraqi Geological Journal
Aswad et al.
2023, 56 (2B), 37-50
39
Fig.1. The Locations of the oil fields in Kurdistan and the study area (Sarta, Tawke, and Sirwan Valley)
after (Yesar, 2022)
The Kurdistan region belongs to the Zagros fold belt which holds a high volume of hydrocarbon
and extends along the Turkish to the Iranian border (Jassim and Goff, 2006). This formation was first
described by Wetzel (1950) in Bellen et al. (1959) at Ora fold outcrops around the Amedy district in
Northern Iraq. According to Wetzel (1950), the thickness of the Kurra Chine Formation is 834m at the
type locality. It consists of limestone with dark brown and black colors, with thin to thick bedding of
the dolomite and breccia beds. The examined area is in the high folded zone and is part of the Zagros
fold belt. The Shnrwe Anticline in Halabja City is linked to the structurally researched outcrop area. The
structural analysis of the subsurface Sarta well is associated with the Pirmam Anticline in Erbil, and the
structural study of the subsurface Tawke well is linked with the Tawke Anticline in Zakho. The Taurus-
Zagro fold and thrust belt include the Tawke field. In 2007, the Tawke field started production of oil
and linked with a Turkey-Iraq pipeline to export oil to European marketing. Currently, the production
of crude oil in this field is about 150b/d. The Sarta field is a new field compared to the Tawke field. At
the end of 2020 production started in this field. This field has some water conning problems which
influenced the production. Currently, it has 3000 b/d due to some borehole completion problems.
The tectonics of the studied area involves the movement of the Arabian and Eurasian orogeny. Iraq
is located in the Northeast of the Arabian Plate that collided with the Iranian plate. As a consequence of
this collision, the foreland basin formed, representing the Zagros fold belt. The Zagros fold belt is
divided into four main zones (Fig. 2). According to Aqrawi (1998), Iraq belongs to the Gondwana
Continent beside the Indian and African plates in Paleozoic Era. From the middle Permian to the Triassic
and Jurassic periods rifting and extension formed which leads to the break of the Gondwana continent
and formed the NeoTethys Ocean (Al-Sharhan and Nairn, 2003). Carbonate rocks were the main
Iraqi Geological Journal
Aswad et al.
2023, 56 (2B), 37-50
40
sedimentary rocks that formed during that period. Clastic rocks are formed by the fluvial deltaic
depositional environment. The highest thickness of Neotethys reached 4000 km during Late Triassic
(Kurrachine Formation) and middle Jurassic periods (Sadooni and Alsharhan, 2004).
Fig.2. The location and tectonic map of the studied area (after Edlibi et al., 2021)
The current research is running pyrolysis for outcrop samples and two subsurface sections. The
outcrop section is located 15km far from the southeast of Halabja city. It is located between Boyen and
Sazan villages. It is about 2.4 km from Boyen Village and 4km from Sazan Village. It locates at the
border between Iraq and Iran. The coordinate system of the studied area in Sirwan valley is located
between 35º 05' 35" N and 46º 05' 58" E. the coordinate system of the Sarta oil field is located between
43º58' 20.399" E and 36º31' 39.228" N coordination. the coordinate system of the Tawke oil field is
located between 42º58'11.1"E and 37º09' 25.6" N coordination (Fig. 2).
Kurra Chine Formation underlies Baluti Formation and overlies the Galikhana Formation. The
lower contact of the Kurra Chine Formation is unconformable whereas its upper contact is conformable
(Bellen et al., 1959).
Iraqi Geological Journal
Aswad et al.
2023, 56 (2B), 37-50
41
2. Materials and Methods
A total of 26 cutting samples have been selected from Kurra Chine Formation from two subsurface
wells and one outcrop at different locations in Northern Iraq (Fig. 3). Samples were taken from DNO
Oil company at Zaxo -Tawke oil field and Genel Energy oil company at the Erbil Sarta oil field. The
surface samples were from Sirwan valley at Halabja, near the Iraqi- the Iranian border (Fig. 4). Samples
were analyzed at Soran University research center and Tehran University. The subsurface samples were
crushed and powdered. We analyzed these samples by RockEval analysis by pyrolysis method. Pyrolysis
analyses were performed on twenty-six cutting and outcrop samples of the Kurra Chine Formation
(Table 1). Approximately 90–100 mg of each sample was prepared for pyrolysis and run on Vinci
RockEval 6 after calibration against standards. The obtained parameters include TOC (wt.%), the free
hydrocarbons (S1), the hydrocarbons that can be generated (S2), the amount of carbon dioxide (CO2)
released through heating organic matter (S3), and the highest temperature for generating a maximum
amount of hydrocarbon during pyrolysis (Tmax). Moreover, the hydrogen index (HI), oxygen index
(OI), and production index (PI) can be calculated from pyrolysis analysis based on the (Peters, 1986).
Fig.3. The collected samples from the studied area A)- Cuttings sample from Sarta and Tawke oil fields
in the Ministry of Natural Resource of Kurdistan B)- Outcrop samples from Sirwan Valley
3. Results
3.1. Quantity of Organic Matter and Hydrocarbon Potential
Two useful measurements related to the quantity of OM are the TOC and the fraction of TOC that
is generated as hydrocarbons and other compounds by pyrolysis (hydrocarbon index or HI). TOC, S2,
and HI are used to describe potential source rocks (table 1).
TOC is playing a role in the identification of the organic matter in the rock samples. The TOC is
varied from section to section. The TOC wt.% of the Sarta Well ranges between (0.43–2.51). Kurra
Chine Formation in the Sarta well as fair to very good hydrocarbon potential. The TOC wt.% of the
Tawke Well ranges between (0.13–1.52). Kurra Chine Formation in the Tawke well has poor to good
hydrocarbon potential. The TOC wt.% of the Sirwan Valley outcrop ranges between (0.02–0.32). Kurra
Chine Formation in the Sirwan surface samples has poor hydrocarbon potential (Fig. 5).
Iraqi Geological Journal
Aswad et al.
2023, 56 (2B), 37-50
42
Table 1. The results of rock eval pyrolysis from the Tawke and Sarta oil fields and Sirwan Valley
outcrop
Section
Sample
Depth
(m)
S1
S2
S3
Tmax
PI=
S1/(S1+S2)
TOC
wt.%
HI
OI
TI=
S1/TOC
HC
index=S2/S3
Tawke
Oil
field
3870
0.26
0.78
0.29
432
0.25
0.37
212
78
0.70
2.69
3880
0.32
1.05
0.55
429
0.23
0.27
390
203
1.19
1.91
4120
0.41
0.79
0.58
436
0.34
0.45
173
128
0.91
1.36
4130
0.15
0.64
0.27
436
0.19
0.34
187
78
0.44
2.37
4150
0.21
0.8
0.58
431
0.21
0.47
172
124
0.45
1.38
4160
0.27
0.76
0.24
439
0.26
0.46
163
52
0.59
3.17
4170
0.65
1.52
0.41
434
0.30
1.15
132
36
0.57
3.71
4200
1.02
3.44
0.83
433
0.23
1.52
226
55
0.67
4.14
4210
0.49
1.1
0.4
433
0.31
0.76
145
53
0.64
2.75
4230
0.4
0.92
0.27
436
0.30
0.92
100
29
0.43
3.41
4240
0.44
0.85
0.31
435
0.34
0.48
180
65
0.92
2.74
4300
0.17
0.31
0.29
427
0.35
0.13
243
225
1.31
1.07
4320
0.42
0.69
0.34
425
0.38
0.26
261
131
1.62
2.03
4530
0.28
0.74
0.34
435
0.27
0.2
365
168
1.40
2.18
Sarta
Oil
field
Sample
S1
S2
S3
Tmax
PI=
S1/(S1+S2)
TOC
wt.%
HI
OI
TI=
S1/TOC
HC
index=S2/S3
3470
0.59
0.88
0.36
395
0.4
0.86
150
188
1.64
2.44
3520
0.57
1.54
0.36
405
0.27
0.43
358
360
1.58
4.28
3570
4.13
4.42
1.82
300
0.48
2.5
177
238
2.27
2.43
3620
3.12
3.88
1.59
301
0.45
2.51
155
234
1.96
2.44
3670
3.08
2.56
0.87
298
0.55
1.5
171
200
3.54
2.94
Sirwan
Valley
Sample
No. and
interval
(m)
S1
S2
S3
Tmax
PI=
S1/(S1+S2)
TOC
wt.%
HI
OI
TI=
S1/TOC
HC
index=S2/S3
S3
(12) m
0.01
0.01
0.01
597
0.51
0.13
8
8
1.00
1.00
S6
(19) m
0.06
0.09
0.08
505
0.40
0.32
28
25
0.25
1.13
S15
(34) m
0.02
0.02
0.03
339
0.49
0.07
29
43
0.67
0.67
S45
(109)
m
0.03
0.02
0.03
410
0.61
0.02
150
150
1.00
0.67
S47
(115)
m
0.03
0.01
0.02
343
0.68
0.11
9
18
1.50
0.50
S49
(120)
m
0.01
0.02
0.02
346
0.38
0.03
67
67
0.50
1.00
S56
(157)m
0.01
0.01
0.02
338
0.55
0.03
33
67
0.50
0.50
TOC = Total Organic Carbon, wt%; S1 = Free hydrocarbon content, mg HC/g rock; S2= Remaining
hydrocarbon generative potential, mg HC/g rock; S3 = Carbon dioxide yield, mg CO2/g rock; HI:
Hydrogen Index = S2×100/TOC, mg HC/g TOC; OI: Oxygen Index =S3×100/TOC, mg CO2/g TOC;
Tmax = Temperature at maximum of S2 peak; PI: Production Index = S1/(S1+S2); GP: Genetic Potential
= (S1+S2), Kg HC/Ton rock.
Iraqi Geological Journal
Aswad et al.
2023, 56 (2B), 37-50
43
Fig. 4. Stratigraphic column and field photographs. It shows the lower and upper contact of the Kurra
Chine Formation with the Galikhana and Baluti Formations. Also, it shows the location of the pyrolysis
samples
Generation potential GP is determined by the hydrocarbon potential of the rocks. GP is calculated
by submitting S1+S2. GP value for the Sarta oil field is approximately between 1.47 to 8.55mg/g which
indicates high generation potential. GP value for the Tawke oil field is approximately between 0.46 to
4.47 mg/g which indicates medium generation potential. GP value for the Sirwan outcrop is
approximately between 0.02 to 0.11 mg/g which indicates a low generation potential table 2.
Iraqi Geological Journal
Aswad et al.
2023, 56 (2B), 37-50
44
Table 2. The GP for the studied area
Fig.5. Quality of the organic matter based on petroleum potential (PP) and TOC% for the analyzed
samples
Section
Depth (m)
S1
S2
GP= S1+S2
Tawke Oil field
3870
0.26
0.78
1.04
3880
0.32
1.05
1.37
4120
0.41
0.79
1.2
4130
0.15
0.64
0.79
4150
0.21
0.8
1.01
4160
0.27
0.76
1.03
4170
0.65
1.52
2.17
4200
1.02
3.44
4.46
4210
0.49
1.1
1.59
4230
0.4
0.92
1.32
4240
0.44
0.85
1.29
4300
0.17
0.31
0.48
4320
0.42
0.69
1.11
4530
0.28
0.74
1.02
Sarta Oil field
Sample
interval
S1
S2
GP= S1+S2
3470
0.59
0.88
1.47
3520
0.57
1.54
2.11
3570
4.13
4.42
8.55
3620
3.12
3.88
7
3670
3.08
2.56
5.64
Sirwan Valley
Sample
S1
S2
GP= S1+S2
S3 (12) m
0.01
0.01
0.02
S6 (19) m
0.02
0.09
0.11
S15 (34) m
0.02
0.02
0.04
S45 (109) m
0.03
0.02
0.05
S47 (115) m
0.03
0.01
0.04
S49 (120) m
0.01
0.02
0.03
S56 (157)m
0.01
0.01
0.02
0.10
1.00
10.00
100.00
1000.00
0.1 1 10 100
PP (mg HC/g rock)
TOC (wt%)
Tawke
Sarta
Sirwan Valley
Fair
Poor
Good
Very Good
Iraqi Geological Journal
Aswad et al.
2023, 56 (2B), 37-50
45
3.2. Types of the Organic Matter
The hydrogen index (HI) vs. oxygen index plot can be used to describe the type of OM. One of the
most relationships to identify the type of organic matter is the Van Krevelen diagram (Peter, 1986). The
hydrogen index (HI) vs. Tmax plot can be used to describe the types of Organic Matter. Sarta oil field
samples show different types of organic matter which are oil-gas pron and gas pron. Tawke oil field
samples show three types of organic matter which are Oil pron, oil-gas prone, and gas pron. In contrast,
Tmax will not give the correct organic matter for outcrop samples due to the low value of S2 (Peter,
1986).
Fig.6. Types of the organic matter of the studied samples based on HI and Tmax plots
Iraqi Geological Journal
Aswad et al.
2023, 56 (2B), 37-50
46
3.3. Maturity of the Organic Matter
The level of thermal maturation can be roughly estimated from the HI vs. OI plot described above.
In general, PI and Tmax values less than about 0.1 and 435 C, respectively, indicate immature OM. A
Tmax greater than 470 C represents the wet-gas zone. The PI reaches about 0.4 at the bottom of the oil
window (beginning of the wet-gas zone) and increases to 1.0 when the hydrocarbon-generative capacity
of the kerogen has been exhausted. Usually, some SI will remain as adsorbed dry gas, even in highly
postmature rocks. The Tmax and PI are crude measurements of thermal maturity and are partly
dependent on other factors, such as the type of OM.
PI of the Sarta samples ranged between 0.27 and 0.55 for Tawke samples ranged between 0.19 and
0.38 and for Sirwan Valley between 0.18 and 0.60. Analyzed samples show a different level of
maturation for each section. Samples from the Sarta oil field show an immature to mature level while
samples from the Tawke oil field show a mature level. Outcrop samples were incorrect due to the value
of S2 which is less than 0.2 (peter, 1986) (Fig. 7). The different ratio for the level of maturation is
different from location to location due to Tmax changes. Also, the type of organic matter will change
the level of maturation.
Fig.7. Level of maturity based on the relationship between Tmax and PI for the subsurface of the
studied samples
3.4. Kerogen Types
Kerogen types can be identified by plotting HI and OI relationships. Sarta oil field samples ranged
between 150 to 358 HI and 188 to 360 OI. This indicates type II to III and type III to IV. The Tawke oil
field samples ranged between 100 to 390 HI and 36 to 225 OI. This indicates type II to III. Sirwan
outcrop samples ranged between 8 to 150 HI and 8 to 150 OI. This indicates type III to IV Fig. 8).
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
290 315 340 365 390 415 440 465 490 515
Production Index (PI)
Maturity (based on Tmax ,oC)
Tawke
Sarta
Condensate -
Wet Gas Zone
Overmature
Intensive
Generation,
Expulsion
Low Level conversion
Dry Gas Window
Immature
Oil
Window
High Level Conversion
Iraqi Geological Journal
Aswad et al.
2023, 56 (2B), 37-50
47
Fig.8. Kerogen types identification based on OI and HI plot in three sections of the studied samples
4. Discussion
Source rock evaluation has been done based on the pyrolysis parameters. TOC was a major
parameter for the identification of the source rock evaluation. According to Peters (1986), Hunt (1996),
and Walters (2006), when TOC contents from a rock with more than 1Wt. % is considered a good source
of the rock. So, Kurra Chine Formation at the Sarta oil field will be a good source rock because most of
the samples contain TOC above 1 Wt.%. at the Tawke oil field, Kurra Chine Formation only at depths
4700 to 4200m contents TOC above 1 Wt.% while an entire remaining depth of less than 1%. On the
other hand, all the samples from Sirwan valley at outcrop show less than 1% of TOC. Thus, TOC
variation between wells and outcrop samples is related to some factors which are organic matter, rate of
sedimentation, and depositional environment (Tyson, 1995). According to peter (1986), the samples that
contain S2 less than 0.2 then give inaccurate Tmax because outcrop samples were oxidized. May need
further study because it could be highly oxidized in the studied area. The quality of the source varied
from location to location due to organic matter content, level of maturation, and sedimentation factors.
According to Al-Hamdani et al. (2021) found Kurra Chine in different depositional environments from
Ramp to Inner Ramp. Sarta Oil filed showed the good quality of source rock while Tawke and Sirwan
showed fair and poor respectively. Tmax was a high influence on the level of maturation of the samples.
Kurra Chine Formation has a similar level of maturity in subsurface samples while less mature in outcrop
samples compared to Al-Dolaimy (2021b). Sarta samples showed an mature level of maturation while
Tawke showed a mature level of maturation. Fig. 9 shows the quality of the organic matter in study
samples. Kurra Chine Formation is high TOC and low S1 and S2 compared to Edlibi et al. (2019).
0
100
200
300
400
500
600
700
800
900
1000
0 100 200 300 400 500
HI
OI
Tawke
Sarta
Sirwan
Type I
Type II
Type IV
Type III
Iraqi Geological Journal
Aswad et al.
2023, 56 (2B), 37-50
48
Kerogen types can be classified based on the relationship between HI, S2, and S3 ratios, Peters and
Cassa (1994) (table. 3).
Figs. 6 and 8 show different types of kerogen in the Kurra Chine Formation. They are II, III, and
IV kerogen types. Balaky et al. (2022) identified shale in Kurra Chine as a heterogeneity that highly
reduced the quality of the pore spaces.
Fig.9. The quality of the organic matter in three sections of the studied samples
Table 3. kerogen types and maturity level based on Peters and Casan (1994)
Kerogen
Type
HI
(mg HC/g TOC)
S2 / S3
Atomic H/C
Main expelled at
peak maturity
I
> 600
> 15
> 1.5
Oil
II
300 – 600
10 - 15
1.2 - 1.5
Oil
II/III
200 – 300
5 - 10
1.0 - 1.2
Mixed oil + gas
III
50 – 200
1 - 5
0.7 - 1.0
Gas
IV
< 50
< 1
< 0.7
None
5. Conclusions
The following were concluded of the study
• Kurra Chine Formation contains high TOC (total organic matter) in the Sarta Oil field samples
while fair to poor in Tawke and Sirwan Valley samples respectively.
• Kurra Chine Formation has good quality organic matter in the Sarta Oil field while fair to poor in
Tawke and Sirwan Valley respectively.
• Samples from the Sarta oil field show an immature to mature level while samples from the Tawke
oil field show a mature level. Outcrop samples vary from immature, mature, and post-mature levels.
• Kerogen types of the Tawke Oil field were type II and III while the Sarta Oil field and Sirwan
Valley were types (II-III, III-IV, and III-IV) respectively.
The low rate of S2 at Outcrop samples was identified which gave inaccurate Tmax in all plots.
Excell
ent
Good
Fair
Excellent
Fair
Good
V.good
Poor
Poor
HI=50
HI=20
HI=100
HI=200
HI=600
HI=1000
Iraqi Geological Journal
Aswad et al.
2023, 56 (2B), 37-50
49
Acknowledgments
The authors would like to thank the Earth Sciences and Petroleum Department for conducting this
research and for lab use. The authors would like to thank the Ministry of Natural Resources for providing
the cutting samples. The authors would like to thank Tehran and Soran University for analyzing the
samples at the laboratory. The authors would like to thank Dr. Rushy Samad and Dr.Sameer for their
help during the sample analysis and processes. The authors would like to thank Mr. Bzhar and Mr. Goran
Fakher, for their help in mapping and sample transferring. The authors would like to thank Mr. Eugene
Sam Okyere for his help in language corrections.
References
Al-Ameri, T.K., Al-Dolaimy, Q.H., Al-Khafaji, A.J., 2009. Palynofacies and hydrocarbon generation potential
of the upper Triassic Kurrachine Formation and lower part of the Baluti Formation, Mosul Block,
Northwestern Iraq. Arabian Journal of Geosciences 2, 273-283
Al-Dolaimy, A.M.S., Al-Beyati, F.M., Al-Mallah, A.Y., 2021a. Distribution of steranes and triterpenes
biomarkers as an indication of depositional environment and maturity of sargelu and kurra chine
formations in different wells in northern Iraq. Iraqi Geological Journal 54, 87–100
Al-Dolaimy, A.M.S., Al-Mallah, A.Y., Abdel-Fattah, M.I., Al-Beyati, F.M., 2021b. Source rock characteristics
of Sargelu and kurra chine formations from the selected wells in northern Iraq. Iraqi Geological Journal 54,
60–74.
Al-Hamdani, A.M., Ali, M.S., Al Dabagh, M.M., 2021. Microfacies Valuation of Kurra Chine Formation (Late
Triassic) and Scenario of Depositional Basin Development in Northern and North Western Iraq. Journal of
Petroleum Research & Studies, (33).
Al-Sharhan A.S., Nairn A.E., 2003. Sedimentary basins and petroleum geology of the Middle East. Elsevier
Science.
Aqrawi, A.A., Goff, J.C., Horbury, A.D., Sadooni, F.N., 2010. The petroleum Geology of Iraq. Scientific press
Ltd.
Aqrawi, A.A.M., 1998. Paleozoic Stratigraphy and Petroleum Systems of the Western and Southwestern Deserts
of Iraq. GeoArabia 3, 417–418. https://doi.org/10.2113/geoarabia0302417.
Awdal, A., Healy, D., Alsop, G.I., 2016. Fracture patterns and petrophysical properties of carbonates
undergoing regional folding: A case study from Kurdistan, N Iraq. Marine Petroleum Geology, 71, 149–
167.
Balaky, S.M., Al-Dabagh, M.M., Asaad, I.S., Tamar-Agha, M., Ali, M.S., Radwan, A.E., 2022.
Sedimentological and petrophysical heterogeneities control on reservoir characterization of the Upper
Triassic shallow marine carbonate Kurra Chine Formation, Northern Iraq: Integration of outcrop and
subsurface data.Marine and Petroleum Geology, 106085.
Bellen, R.C., Dunnington, H.V., Wetzel, R., Morton, D.M., 1959. Lexique Stratigraphic International Paris, V.
ІІІ, Asia, Fascicule 10a Iraq, 333.
Edilbi, A.N.F., Kolo, K., Muhammed, N.R., Yasin, S.R., Mamaseni, W.J., Akram, R., 2019. Source rock
evaluation of shale intervals of the Kurra Chine Formation, Kurdistan Region-Iraq: An organic geochemical
and basin modeling approach. Egyptian Journal of Petroleum 28, 315–321.
Hunt, J. M., 1996. Petroleum Geochemistry and Geology, 2nd ed. W.H. Freeman and Company, New York, 743.
Jassim, S.Z., Goff, J.C., 2006. Geology of Iraq, Prague and Moravian Museum, Brno, Czech Republic, Dolin.
Lunn, G.A., 2020. Dating and correlation of the Baluti Formation, Kurdistan, Iraq: Implications for the regional
recognition of a Carnian “marker dolomite”, and a review of the Triassic to Early Jurassic sequence
stratigraphy of the Arabian Plate. Journal of Petroleum Geology, 43(1), 109-125.
Peters, K. E., Cassa, M. R., 1994. Applied source rock geochemistry, chapter 5. In Magoon L. B. and W. G. Dow,
eds, The petroleum system-from source to trap: American Association of Petroleum Geologists Memoir,
60, 93-120.
Iraqi Geological Journal
Aswad et al.
2023, 56 (2B), 37-50
50
Peters, K. E., 1986. Guidelines for evaluating petroleum source rock using programmed pyrolysis, The American
Association of Petroleum Geologists Bulletin, 70 (3), 318-329.
Sadooni, F.N., 1995. Petroleum Prospects of Upper Triassic Carbonates in Northern Iraq. Journal of Petroleum
Geology 18, 171–190.
Sadooni, F.N., Alsharhan, A.S., 2004. Stratigraphy, lithofacies distribution, and petroleum potential of the Triassic
strata of the northern Arabian plate. American Association of Petroleum Geologists Bulletin 88, 515–538.
Tissot, B.P., Welte, D.H., 1984. Petroleum Formation and Occurrence: A New Approach to Oil and Gas
Exploration, 2nd ed.: Springer-Verlag, Berlin, 699.
Tyson, R.V., 1995. Sedimentary Organic Matter-Organic Facies and Palynofacies. Chapman and Hall, London,
615.
Yesar, A. 2022. Iraqi Kurdistan Gas Expansion Work Suspended After Attacks.
