Introduction

The subsurface Cretaceous sediments cover a wide area of the Northern Western Desert of Egypt and include many structurally controlled sedimentary basins where various rock facies were deposited. Western Desert has exceptional hydrocarbon potentiality and is considered an important oil province in Egypt. The north Western Desert tectonically lies in the unstable shelf (Hantar 1990). This area is characterized by two main fault trends: the first formed contemporaneous with the opening of the Neo-Tethys corresponds the Jurassic rift, and the second corresponds the Cretaceous faults. This is accompanied by periods of compressive tectonism (Deformation of the Syrian Arc). Another important aspect was the dextral or sinistral rotation of the North African plate relative to Laurasia, which had a robust modifying effect on the regional tectonic basin styles encountered in North East Africa, especially the Western Desert (EGPC 1992). Western Desert comprises eight Mesozoic basins (Shushan, Matruh, Kattaniya, Qattara, Dahab-Mireir, Natrun, Alamein, and Abu Gharadig) and a Tertiary basin (Gindi Basin). The Western Desert has been subjected for several palynological, organic geochemical, and hydrocarbon potential studies. Palynological studies play a great role currently in upstream sector. In Egypt, these investigations were started by the work of Urban et al. (1976) and followed by a series of authors (e.g., Parker 1982; Abu El Naga 1984; Labib 1984; Schlumberger 1984; unpublished report of Robertson Research International and associates; Kholeif et al. 1986; Barakat et al. 1987, 1988; Abd El-Aal and Moustafa 1988; Nakhla et al. 1992; El Beialy 1995; Schrank and Ibraheim 1995; Ibrahim 1996; Mahmoud and Moawad 2002; Baioumi and Maky 2004; Ibrahim et al. 2009; Zobaa et al. 2011; El Beialy et al. 2010; Aboul Ela and Tahoun 2010; Tahoun 2012; Tahoun et al. 2015; Tahoun and Mohamed 2013, 2020, 2015; Aboul Ela et al. 2018, 2020; Mansour et al. 2020a, 2020b). Most of these studies evaluated source rock characteristics, both qualitatively and quantitatively using traditional TOC/Rock-Eval pyrolysis along with palynofacies and palynomorph microscopy. Recently, Mohamed et al. (2019) presented a detailed palynological study, mainly of the marine-inhabited dinoflagellate cyst and their marker species for biostratigraphic reconstruction of the Santonian-Oligocene interval of the studied Drazia-1 well. This well was drilled in the East Yidma field of the Alamein Basin that is located in the northern part of the Egyptian Western Desert northeast of the Qattara Depression (Fig. 1). In the present work, we deal with the organic content of the syn Syrian Arc deposits (Khoman, Appolonia, and Dabaa formations) to discuss the relationship of the tectonic activities in the region with palynofacies change in addition to the economic importance of the study interval in the giant Alamein Basin. Therefore, we focus on a detailed microscopy through optical analysis to determine palynofacies types and the distribution of the sedimentary organic matter (SOM) in the three formations of the Drazia-1 well. Additionally, detailed characterization of hydrocarbon potential, based on TOC/Rock-Eval pyrolysis, was carried out along with the determination of Kerogen types and thermal maturity levels of the studied rock units. Generally, Alamein, Yidma, Agar, Razzak, and Horus oil fields of the Qattara–Alamein ridge are produced primarily from the Aptian Alamein dolomite and from the Cenomanian Bahariya and Abu Roash “G” reservoirs.

Fig. 1
figure 1

(A) Location map of the studied Drazia-1 well in the Alamein Basin and (B) the tectonic setting map of the study area in the context of the main Mesozoic and Early Cenozoic basins (white) of Egypt modified after Yousef et al. (2019)

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Sedimentary organic matter (SOM) analysis has been effectively employed to offer valuable source rock information when compared to the expensive instrumental geochemical analyses such as Rock-Eval pyrolysis, vitrinite reflectance (Ro%), and gas chromatography-mass spectrometry (cf. Zobaa et al. 2011; Deaf and Tahoun 2018; Aboul Ela et al. 2018; Tahoun et al. 2018; Gentzis et al. 2018a, 2018b; Deaf et al. 2020; Mansour et al. 2020c, 2020d). Tyson (1995) defined the palynofacies analysis as the palynological study of the depositional environments and hydrocarbon source rock prospective relied upon the overall assemblage of particulate organic matter. Moreover, palynofacies analysis can be useful in the interpretation of the tectonic activity in sedimentary basin, since it can distinguish the proximal-distal source of organic matter. The petroleum geochemistry is an applied science for the determination of productive and non-productive zones and properties of source rocks, oil migration, development of oil fields, and continuous production (El Nady et al. 2015).

Geological setting

Drazia-1 well is located in East Yidma Oil Field of Alamein Basin, north western Egypt (latitude 30° 48′ 38.1″ N and a longitude 28° 57′ 37.3″ E). Stratigraphically, it includes three rock units: (1) the Khoman formation that is characterized by open marine deposits and composed of two main units—the lower unit is frequently massive dolomitic limestone with brownish-gray shale interbeds and unconformably overlies the Abu-Roash formation, mainly in the structurally higher area (Mahsoub et al. 2012). The upper unit is described as a white fine-grained, dolomite, and chalky massive limestone intercalated with chert bands (Fig. 2) with poor reservoir properties (Mahsoub et al. 2012). In the Drazia-1 well, Khoman formation extends in depth from 5990 to 5060 ft and ranges in age from Santonian to Maastrichtian (Mohamed et al. 2019). (2) The Apollonia formation consisted of white chalky limestone with minor shale. It overlies the Khoman formation and ranges in age from Paleocene to Middle Eocene (Mohamed et al. 2019). It extends over a depth interval from 5060 to 4710 ft (Fig. 2). (3) The Dabaa formation is consisted of greenish-gray shale, mostly ferruginous in its lower part. It covers the depth interval from 4710 to 3444 ft. This rock unit struggles from late Eocene to Oligocene (Mahsoub et al. 2012; Mohamed et al. 2019, Fig. 2).

Fig. 2
figure 2

Lithostratigraphic column of the studied formation and the TOC content in the Drazia-1 well, Western Desert

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In the Alamein Basin, the first Syrian-Arc inversion event took place in the Abu Roash formation, producing folds and faults, and uplifting structures. In the cores of the inversion anticlines, the Santonian and older rock units were completely eroded. The Khoman formation deposited in Tectonosequence 3 (syn-inversion) as a result of the main phase of transgression which commenced in the Campanian and led to high sea levels in the Maastrichtian. (Yousef et al. 2019). The Khoman unit thins above the crests of the hanging-wall inversion anticline structures, but illustrates remarkable thickness variations in the region of the inversion structures, demonstrating that inversion took place during the time of deposition. The Paleocene-Oligocene Apollonia and Dabaa rock units were deposited in the Tectonosequence 4 (late syn-inversion), due to compressional and persistence of the Late Cretaceous folding event which led to onlap at its margins, but with a magnitude less than that of Tectonosequence 3 (Yousef et al. 2009, 2019). The third tectonic event (Syrian Arc event) through the Late Cretaceous to Eocene age inverted several basins of the Western Desert and significantly ended generation and petroleum migration in many areas by the Early Oligocene time, which caused the cessation of hydrocarbon migration from deeper Cretaceous and Jurassic source rocks (Sedek and Al Mahdy 2012).

Materials and methods

Palynofacies analysis

A total of 59 cutting samples were recovered from the Drazia-1 well drilled in the East Yidma oil field by the Ina Naftaplin Company in March 2006. About 10–15 g was subjected to routine palynological extraction techniques (Batten 1999). All microscope slides and residues were kept in the Geology Department, Minia University, Egypt. In the present work, a total of 1000 particles per sample were counted and classified according to Tyson (1993, 1995) into three main groups: palynomorphs group (i.e., spores, pollen grains, dinoflagellate cysts, achritarchs, foraminiferal test linings, and fresh water algae), phytoclasts group (i.e., opaque and semi-opaque plus translucent woody particles), and AOM group (i.e., AOM and resin). These groups are illustrated in Tables 1 and 2. To statistically represent the counted data, a cluster analysis of samples was constructed using the statistical program (Past program of Hammer et al. 2001) to characterize the studied succession of the Drazia-1 well into distinctive palynofacies assemblages (Fig. 3a). The counted samples were then plotted on the ternary diagram of Tyson (1993), which comprises the three kerogen-end members AOM, phytoclasts, and palynomorphs (Fig. 3b).

Table 1 Quantitative distribution of the palynofacies categories in the Drazia-1 well (depth of 4020–4990 ft), Western Desert
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Table 2 Quantitative distribution of the palynofacies categories in the Drazia-1 well (depth of 5000–5990 ft), Western Desert
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Fig. 3
figure 3

a Cluster analysis of the studied samples in the Khoman, Apollonia, and Dabaa formations; cluster A is phytoclast-AOM assemblage and cluster B is AOM assemblage. b AOM-palynomorph-phytoclast ternary plot (after Tyson 1993) of the relative numerical particle frequency (% of the total POM content) in Drazia-1 well, Western Desert, Egypt

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Total organic carbon (TOC) and CaCO3

Good oil-prone source rocks are one of the three major total petroleum system elements, besides intensive reservoirs and excellent seals. Among the critical aspects for source rock studies are the quantities of organic matter accumulated throughout deposition and alterations of the post depositional digenesis, and thermal maturation degree (Peters 1986; Peters and Cassa 1994).

For an interval to be a source rock of hydrocarbon generation, it should contain not only appropriate amounts of organic matter, but also the S2 values that represent the amount of hydrocarbons that might be produced if thermal maturation continues (Batten 1996). In the present study, thirty-nine samples were measured for their TOC using a LECO C230 carbon analyzer (Table 3) and carried out in the Department of Geodynamics and Sedimentology, University of Vienna. The carbonate content (CaCO3) was calculated using the formula

Table 3 The TOC measurements in Drazia-1 well in Western Desert
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CaCO3 = inorganic carbon × 8.333.

The minimum values that were taken for a probable source rock interval was 0.5 wt% TOC as a cutoff for fine clastics and shales and around 0.3 wt% for carbonates (e.g., Hedberg et al. 1979). Peters (1986) rated a content of TOC < 0.5 wt% as poor, 0.5–1 fair, 1–2 good, and greater than 2.0 very good, whereas Peters and Cassa (1994) noted that a minimum organic carbon content of a source rock should be within the range of 1–2 wt%.

Rock-Eval pyrolysis

Valuable information concerning the quantity, quality (type), and thermal maturity of the organic matter in a sedimentary rock can be provided by the Rock-Eval pyrolysis data (Espitalie et al. 1977. After the primary TOC showing, all samples measuring over than 1.5 wt% TOC were selected for the Rock-Eval pyrolysis in 10 distinct intervals (Table 3). Rock-Eval pyrolysis comprises passing a stream of helium through 100 mg of crushed rock heated firstly at 300 °C followed by heating at 25 °C/min to 550 °C. The vapors are analyzed with a flame ionization detector (FID) and the emitted CO2 by heating at 390 °C and is measured by thermal conductivity detector (TCD). The resulting parameters comprise S1 (free hydrocarbons), S2 (hydrocarbon yield from thermal cracking of kerogen), S3 (the trapped CO2 freed during pyrolysis), and Tmax (Rock-Eval pyrolysis oven temperature °C at maximum S2 generation). Hydrogen index (HI) is a calculated parameter based mainly on the measured TOC and S2 values [HI = (S2/TOC) × 100, mg HC/g TOC]. Oxygen index is also a calculated parameter from the formula [OI = (S3/TOC) × 100, mg CO2/g TOC]. Production index is the ratio between the released free hydrocarbons (S1) and total hydrocarbons of thermal cracking (S1 + S2), pyrolyzable carbon index; [PCI = 0.83 × (S1 + S2)] and S2/S3 together with HI are relative to the quantity of hydrogen in the kerogen and can designate the potential of the rock to generate oil (Hunt 1996). The measured values of samples by the Rock-Eval pyrolysis are summarized in Table 4.

Table 4 Guidelines for pyrolysis parameters of quality, quantity, and thermal maturity in Drazia-1 well, Western Desert (adapted and modified after both Tyson (1995) and Peters and Cassa (1994))
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Results

Palynofacies assemblages

A palynofacies is defined as the complete assemblage of organic matter and palynomorphs in a fossil deposit. Palynofacies analysis includes the incorporated study of the entire aspects of the organic matter assemblage, which includes the recognition of the individual particulate components, estimation of their relative and absolute proportions, and their size and preservation states (Combaz 1980).

The palynofacies analysis in the Drazia-1 well reflects a high abundance of AOM in the Upper Cretaceous succession compared to high concentration of brown and black phytoclasts in the Paleocene-Oligocene interval (Tables 1 and 2).

The statistical analysis based on the ratio of sedimentary organic material groups (palynomorphs, phytoclasts, and AOM) encountered through the three formations enabled us to differentiate two palynofacies assemblages based on cluster analysis into clusters A and B using the Ward’s method of the PAST program (Fig. 3a). Moreover, all samples were plotted on the AOM-phytoclasts-palynomorphs ternary diagram after Tyson (1993) in order to interpret their depositional environments (Fig. 3b).

Palynofacies type 1 (PF1) assemblage was proposed to cluster A and was dominated by phytoclasts and AOM. It is the dominant palynofacies assemblage in the studied samples and covers the Dabaa and Apollonia formations. It is represented by 21 samples in the Drazia-1 well and ranges from 4020 to 4990 ft, except for two samples at depths of 4844 and 4900 ft. This cluster is typified by a relatively high abundance of phytoclasts (65.5–97.2%) compared to low to high abundance of AOM (9–83%) and low palynomorph content (13–38%) mainly the terrestrial pollen grains and spores but the marine dinoflagellate cysts and acritarchs are very rare in this assemblage (Figs. 3b, 4a, b). The maximum phytoclast content is recognized in sample at a depth of 4960 ft, while the minimum content is observed at a depth of 4990 ft. The phytoclasts are dominated by brown particles of wood tracheid without visible pits as opposed to moderate to low content of black wood debris.

Fig. 4
figure 4

a, b The first palynofacies assemblage that composed mainly of phytoclasts-AOM; the photomicrographs were recovered from the depth interval of 4190 ft in Drazia-1 well. c, d The second palynofacies assemblage that is dominated by the AOM recovered from the sample at a depth of 5930 ft in Drazia-1 well. e Brown wood particles, f lath black phytoclast, g AOM, h dinoflagellate cyst, i foraminifera lining, k spores

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According to the ternary diagram of Tyson (1993), all samples of this cluster plot in the palynofacies fields I and II, which reflect deposition in a highly proximal shelf environment or basin and marginal oxic-dysoxic basin conditions, respectively (Fig. 4a, b). Additionally, these fields indicate kerogen type III of gas-prone hydrocarbons.

Palynofacies type 2 (PF2) assemblage was assigned to samples of cluster B and is considered the dominant palynofacies assemblage in the studied Khoman formation. This palynofacies includes 37 samples and ranges from 5000 to 5990 ft, except for a sample at depth of 5660–5670 ft. This palynofacies assemblage of cluster B is characterized by a relatively high abundance of AOM (74.6–92.4%); however, the sample depth 5660–5670 ft contains a relatively low AOM content (33.1%, Figs. 3b, 4c, d).

Most of the samples of the second palynofacies assemblage plot in the field IX of Tyson (1993), except for one sample that has a relatively high palynomorph content and plot in the palynofacies field VI. Additionally, one more sample plot in the palynofacies field VIII (Fig. 3b). According to Tyson (1993, 1995), the palynofacies field IX indicates deposition of samples in a distal suboxic-anoxic basin with low abundance of palynomorphs possibly owing to masking, regularly alginate-rich, deep basin, or stratified shelf-sea sediments, especially sediment-starved basins. Besides, samples of this assemblage contain oil-prone kerogen type II.

Source rock evaluation

The assessment of source rocks in the studied well is based upon the pyrolysis parameters like TOC, S1, S2, HI, OI, Tmax, and VR which provide significant information for petroleum generation potential and characterization (e.g., Peters and Cassa 1994; Tahoun et al. 2018; Gentzis et al. 2018a, 2018b; Deaf et al. 2020; Mansour et al., 2020 b, c). Additionally, common plots such as the modified van Krevelen diagram, the HI versus Tmax plot, Tmax versus PI, and TOC versus S1+S2 diagrams are integrally used to further confirm the potentiality of probable source rock layers and to define the type of produced hydrocarbon and their thermal maturity levels.

Hydrocarbon potential

Peters and Cassa (1994) accounted for measuring the amount of TOC and S2 to evaluate the quantity of organic matter in the studied formations. They revealed that “the samples which have TOC less than 0.5 wt% and S2 less than 2.5 mg/g are considered poor source rocks. Samples contain TOC from 0.5 to 1.0 wt % and S2 from 2.5 to 5 mg/g are fair source rocks. Samples contain TOC from 1 to 2 wt % and S2 from 5 to 10 mg/g are good source rocks and samples that contain more than 2 wt % TOC and S2 > 10 mg/g are considered very good source rocks”. In the present study, the selected samples for Rock-Eval pyrolysis analyses have high TOC content which is good and ranges from 1.1 to 1.7 wt%. The S2 values ranges between 0.66 and 1.36 mg HC/g rock (Table 4), indicating a poor hydrocarbon generating potential and accordingly a poor source rocks in the Khoman, Apollonia, and Dabaa formations. The hydrocarbon generation prospective of a source rock is the sum of the values S1 and S2 (Peters and Cassa 1994). According to Hunt (1996) and Gogoi et al., (2008), the source rocks with a generation potential of < 2 are considered poor, 2–5 fair, 5–10 good, and > 10 very good (Fig. 5). Based on the plot between S1+S2 and TOC, the Khoman, Apollonia, and Dabaa formations have a poor hydrocarbon generation potential (Fig. 5, Table 4).

Fig. 5
figure 5

The generation potential of the studied source rocks as indicated by the relationships between TOC and S1 + S2 (after Gogoi et al. 2008) in Drazia-1 well, Western Desert

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Type of kerogen

The type of organic matter is a significant factor in assessing the source rock potential and has vital control on the nature of the hydrocarbon yields (Hunt 1979; Tissot and Welte 1984; Barker 1996). From the Rock-Eval pyrolysis data, such as HI, various types of organic matter kerogens can be recognized (Waples 1985). HI values that are less than 200 mg HC/g TOC point to a possible source for gas generating (mostly type III kerogen), whereas HI ranging between 200 and 300 mg HC/g TOC contains a mixed kerogen type III/II, and as a result is capable of producing mixed gas and oil (Peters and Cassa 1994).

The investigated samples in Drazia-1 well have low HI values that range from 49.7 to 90.7 mg HC/g TOC, though OI values range from 220.6 to 362 mgCO2/g TOC (Table 4). The HI values usually lie in a typical range of kerogen type III of terrestrial organic matter (e.g., Peters and Cassa 1994; Mansour et al. 2020c). These results are further confirmed by the Van Krevelen diagram (Van Krevelen 1993), whereby all samples plot in the fields of type III to IV kerogens (Fig. 6). Additionally, the HI versus Tmax plot for the studied samples in the Drazia-1 well indicates mainly a kerogen type III of terrestrial woody material typically of gas-prone hydrocarbons (Fig. 7).

Fig. 6
figure 6

HI versus OI of the modified Van Krevelen diagram (after Van Krevelen 1993), showing the type of kerogen in the Drazia-1 well, East Yidma field

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Fig. 7
figure 7

HI versus Tmax plot (after Koeverdon et al. 2011), showing the maturity and type of Kerogen in the analyzed samples of the Drazia-1 well, East Yidma field

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Thermal maturity

Source rock maturity of the studied samples is estimated from the Tmax and production index “PI values.” Many maturity parameters, especially Tmax, based on the type of organic matter, from which they derived (Peters 1986). It was stated that oil generation from source rocks started at Tmax of ca. 435 °C that gradually increases in thermal maturity levels to 465 °C at peak of gas generation (e.g., Peters and Cassa 1994). These values are consistent with the PI values, which commonly range between 0.2 and 0.4.Therefore, the organic matter are in the immature stage for a PI value of less than 0.2, whereas the gas window is consistent with a PI value of more than 0.4 (e.g., Peters and Cassa 1994).

For the studied formations, the pyrolysis Tmax values (Table 4) are below 435 °C, representing that the source rocks are still in the immature stage. The maturity estimates from the HI versus Tmax plot also showed the same maturity level, whereby all samples were in the immature stage. Furthermore, the PI values for the Khoman, Apollonia, and Dabaa formations range from 0.08 to 0.13 in agreement with the Tmax results, which reinforce an immature stage (Fig. 8).

Fig. 8
figure 8

PI versus Tmax (°C) showing the thermal maturation levels of the Drazia-1 well, East Yidma field (adopted after GeoMark sheet)

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Discussion

The palynofacies analysis in the Drazia-1 well reflects two different marine environments. The relatively deeper one which is characterized by a high abundance of AOM and carbonate contents were recognized in the Upper Cretaceous succession (Khoman formation). The relatively shallower environment is characterized by a high abundance of phytoclasts and siliciclastic contents in the Paleocene-Oligocene interval (Dabaa and Appolonia formations). The relative changes in the water depth of the Upper Cretaceous and Paleogene may be related to the variations in the region of the inversion structures by the Syrian Arc System which took place during the time of deposition (e.g., Yousef et al. 2009, 2019). Ruban et al. (2010) confirmed that, in the Northeastern Africa, mainly Western Desert, there is a discrepancy between documented transgression-regression patterns and the eustatic sea level changes in the Paleocene period. The regional subsidence or uplift controlled transgressions and regressions locally. The very low hydrocarbon potential and moderate to low content of organic matter preserved within the studied Khoman and Apollonia formations can be referred to various environmental processes that include carbonate effect during deposition, redox conditions, role of sediment supply, and sedimentation rate (e.g., Mansour et al. 2020a). For this purpose, we plotted the TOC values versus CaCO3 to address the relationship between both variables in the carbonate-rich intervals (Fig. 9). The relationships between TOC versus CaCO3 content were proposed by Ricken (1996). In this model, the CaCO3 content varies and organic matter and siliciclastics were assumed to be constant. In other words, the relative increase in CaCO3 would result in a dilution of accumulated organic carbon content and lead to an overall decrease in the TOC in sediments. For the Khoman and Apollonia formations, a moderate R2 value (0.48) was observed between the TOC and CaCO3 (Fig. 9), confirming a moderate relationship between both variables during deposition within the Late Cretaceous marine ecosystem (e.g., Mansour et al. 2020a, 2020e). Additionally, the normal distribution between samples in Fig. 9 showed a negative correlation, confirming the proposed hypothesis of Ricken (1996). However, redox conditions and role of sediment supply require more geochemical data to be addressed, providing a recommendation for future studies of such important succession.

Fig. 9
figure 9

Plot of TOC versus CaCO3 for carbonate-rich intervals of the Khoman and Apollonia formations to interpret the relationship between both variables during deposition

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The thermal immature stage of the Khoman, Apollonia, and Dabaa formations is thought to be attributed to two main factors, the local to regional tectonic activity and burial thickness of sediments. The northern region of Egypt, including the north Western Desert, Nile Delta, and Sinai Peninsula, has been influenced by several structural processes during the Late Cretaceous to Cenozoic (EGPC (Egyptian General Petroleum Corporation) 1992). This included the Syrian Arc System that initiated from the Turonian-Santonian and reached the main phase of activity during the middle Eocene. Additionally, the other tectonic cycle was represented in the Red Sea opening and Gulf of Suez rifting phase that activated during the Oligocene to Miocene (EGPC (Egyptian General Petroleum Corporation) 1992). Since the studied formations were deposited during the Late Cretaceous to Oligocene, these tectonic activities that influenced northern Egypt are suggested to uplift the sedimentary succession in the studied area. The uplifting consequently reduced the burial depth and led to the immaturity for source rock hydrocarbon.

Conclusion

The palynofacies analysis were carried out on 59 cutting samples. The organic geochemical TOC were conducted on 39 samples and the Rock-Eval pyrolysis was conducted on 10 samples, from the Khoman, Apollonia, and Dabaa rock units in the Drazia-1 well, East Yidma Oil Field, Alamin Basin. Two palynofacies assemblages were proposed for the studied succession. The Paleocene-Oligocene succession was assigned to the first palynofacies assemblage that is typified by a high abundance of brown and black phytoclasts and reinforces deposition in a proximal shelf or basin of gas-prone kerogen type III. A high abundance of AOM in the Upper Cretaceous succession of the second palynofacies assemblage indicates a distal suboxic-anoxic basin of oil-prone kerogen type II. In the Alamien Basin, the palynofacies analysis indicates relatively deeper marine environment in the Upper Cretaceous, since it is characterized by an abundance of marine dinocysts and AOM, and shallower environment in the Paleogene which is characterized by abundance of terrestrial pollen grains, spores, and phytoclasts. This variation is related to the tectonic movements in the northern Egypt, mainly the Syrian Arc System. The local uplifting in the Alamein Basin reduced the burial depth and thermal maturation for organic matter in the Khoman, Apollonia, and Dabaa formations of the Drazia-1 well.

The organic matter content in Khoman, Apollonia, and Dabaa formations of the Drazia-1 well is not potential for those that are gas-prone. Furthermore, the Tmax and PI values indicated that the Khoman, Apollonia, and Dabaa formations were in the immature stage.