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During the Late Cretaceous (Cenomanian), significant disruptions in the carbon cycle, global warming, and episodes of oceanic anoxia occurred, leading to the deposition of organic carbon-rich sediments. In well BED2-3, located in the BED2 gas field within the Abu Gharadig Basin (north Western Desert, Egypt), the lower-to-middle Cenomanian Bahariya Formation displays thick alternating layers of sandstones, siltstones, and shales. Detailed geochemical analyses were conducted on thirty-three cutting samples from the Bahariya Formation, focusing on total organic carbon (TOC), whole-rock elemental geochemistry, and carbonate content. These geochemical measurements provided valuable information regarding paleoredox conditions, marine biological productivity, terrigenous sediment influx, weathering and paleoclimate conditions, and mechanisms influencing organic matter accumulation. The enrichment factors (EF) of redox-sensitive trace elements were utilized to infer oxygenation conditions and marine biological productivity during the deposition of the Bahariya Formation. The stratigraphic distribution of redox-sensitive elements allowed for the Bahariya Formation to be categorized into lower and middle-upper intervals. The results revealed that the lower interval exhibited strong-to-enriched EF values of redox-sensitive elements and fair-to-rich TOC content, indicating a prevalent anoxic setting during deposition. In contrast, the middle-upper interval displayed weakly-to-slightly enriched EF values with poor-to-fair TOC content, suggesting deposition under oxic-suboxic redox conditions. By examining Al-normalized redox-sensitive ratios and their correlations with TOC content, significant relationships were observed in the lower interval, indicating a coupling between the enrichment of redox-sensitive elements and organic matter. This suggests enhanced biological productivity during deposition of the lower interval compared to the relatively low productivity during deposition of the middle-upper interval of the formation. These conditions controlled the production and preservation of organic matter in the lower interval, while the middle-upper interval suffered from organic matter dilution and destruction due to an increased influx of terrigenous material and lower biological productivity. Geochemical proxies related to detrital materials provided evidence of alternating terrigenous sediment flux, consistent with shifts between coarse- and fine-grained fractions and related facies of sandstones, siltstones, and shales. These findings align with active continental weathering in the source terrane and deposition under enhanced warm-humid climatic conditions, with intermittent arid-to-semi-arid phases. These conclusions are further supported by the palynomorph assemblages and clay mineralogy within the Bahariya Formation. [ABSTRACT FROM AUTHOR]

The Middle Jurassic was a time of marginal to shallow shelf settings dominated by organic matter-rich deposition in northern Egypt, southern Tethys. Paleoenvironmental and sequence stratigraphic reconstructions are of paramount significance for a better understanding of basin history and related reservoirs and source rock units. For this purpose, a detailed palynomorph and palynofacies analysis of the Middle Jurassic Khatatba Formation in the Dahab-Mireir Basin, north Western Desert, was conducted. A moderately to well-preserved, moderately diverse palynomorph assemblage of spores, pollen, and dinoflagellate cysts is identified. Marker dinoflagellate cysts, including Dichadogonyaulax sellwoodii, Escharisphaeridia pocokii, Gonyaulacysta adecta, Korystocysta gochtii, Pareodinia ceratophora, and Wanaea acollaris, defined a Bajocian to Callovian age. Palynofacies analysis of the Khatatba Formation revealed two assemblages, whereby PFA-1 is the most abundant in the study well and is comprised mainly of terrestrial phytoclasts deposited nearby fluvio-deltaic sources. The infrequently reported PFA-2 consists of moderate abundances of phytoclasts and AOM, deposited in an inner shelf environment. A more reliable paleoenvironmental interpretation was indicated based on three palynomorph assemblages. The spore-dominated assemblage indicated deposition in a deltaic environment, while the mixed palynomorph assemblage revealed fluvio-deltaic to marginal shallow marine conditions. The microplankton-dominated assemblage is represented by minor samples and reflects an offshore inner shelf condition. Furthermore, the Middle Jurassic relative sea level was reconstructed based on the quantitative variations in the terrestrial/marine (T:M) ratios and abundances of spores, pollen, and dinoflagellate cysts. This led to the subdivide of the Khatatba Formation into thirteen third-order transgressive-regressive sequences, which can be correlated with the global Jurassic short-term sea level changes. Active tectonics and accelerated drifting of the Eurasian Plate during the Middle Jurassic are suggested to control basin uplift/subsidence and, therefore, recurring patterns of relative sea level change. [ABSTRACT FROM AUTHOR]

The Middle Jurassic in the north Western Desert, Egypt, was a time of complex tectonics and increased environmental perturbations attributed to the predominant sedimentation of organic carbon-rich fine siliciclastic and carbonate deposits of the Khatatba Formation. Although some studies have addressed the hydrocarbon potential and source rock characteristics of the Khatatba Formation, a regional-scale investigation of the prevalent paleoenvironmental conditions and organic matter characteristics is still necessary. In this study, the Khatatba Formation is investigated for detailed palynofacies analysis and palynomorph composition to assess organic matter kerogen types and reconstruct the depositional paleoenvironmental patterns on a regional scale. For this purpose, 116 drill cuttings were collected from five wells in the Matruh, Shushan, and Dahab-Mireir Basins. Moderately diverse assemblages of spores, pollen, and dinoflagellate cysts are reported. Age-diagnostic dinoflagellate cysts, including Adnatosphaeridium caulleryi, Dichadogonyaulax sellwoodii, Korystocysta gochtii, Wanaea acollaris, and Pareodinia ceratophora, along with occasional records of Systematophora areolate and Systematophora penicillate, defined a Bajocian–Callovian age. Based on particulate organic matter (POM) composition, four palynofacies assemblages (PFAs) are identified. PFA-1 is the most common within the Khatatba Formation in the five studied wells. It contains high proportions of phytoclast fragments versus low contents of amorphous organic matter (AOM) and palynomorphs and is defined by a gas-prone kerogen Type III. PFA-2 is comprised of moderate abundances of AOM and phytoclast characteristics of oil-prone kerogen Type II. PFA-3 is dominated by phytoclasts and moderate to low proportions of AOM and palynomorphs of kerogen Type III, whereas PFA-4 consists of AOM and palynomorphs defining kerogen Type II. PFA-1 indicates predominant deposition in proximal active fluvio-deltaic sources to marginal marine conditions with enhanced contributions of terrestrial/riverine influx. PFA-2 and PFA-3 reveal deposition under an enhanced dysoxic to anoxic proximal inner neritic shelf due to the abundant occurrences of spores and coastal to shallow marine dinoflagellate cysts. PFA-4 suggests deposition under enhanced suboxic to anoxic distal inner neritic conditions because of enhanced AOM and abundant proximate and some chorate dinoflagellate cysts. Thus, the Middle Jurassic experienced a predominantly marginal to shallow water column in this part of the southern margin of the Tethyan Ocean where the Matruh, Shushan, and Dahab-Mireir Basins were located. [ABSTRACT FROM AUTHOR]

The mid‐Cretaceous period was a time of abnormal polar temperature warming and consequent global oceanic anoxia that enhanced the widespread accumulation of organic matter‐rich marine sediments. The current contribution focuses on the late Albian oceanic anoxic subevent 1d (OAE 1d) that represents a period of increased perturbation of the global carbon cycle. Palynological and geochemical investigations, including TOC/Rock‐Eval pyrolysis and stable carbon isotope of organic matter (δ13CTOC), were conducted for the upper part of the Kharita Formation from the Abu Gharadig Basin, north Western Desert, Egypt, to (a) confirm the age of this unit, (b) assess the depositional environments and prevalent redox conditions, and (c) confirm the occurrence of the OAE 1d within the sedimentary record in this part of the southern Tethys. Based on the TOC content and Rock‐Eval pyrolysis parameters, the organic matter in the upper Kharita Formation is expected to have a limited hydrocarbon generation potential consisting of gas only. The sedimentation patterns and role of continental weathering and runoff influx were assessed through trace element ratios and relationships. Redox conditions were interpreted based on Stotal–TOC relationship, Stotal–TOC–Fetotal ternary plot, Rock‐Eval S2, trace element proxies and relationships (including Cr vs. V + Ni, V/Cr vs. Stotal, and Stotal/Fe vs. Mn/Stotal). The ratio of TOC/Ptotal was implemented to assess both marine primary productivity and oceanic anoxia during this period. Biostratigraphic constraints showed that the upper part of the Kharita Formation spanned a late Albian age (Cretacaeiporites densimurus Interval Zone). Results showed that the OAE 1d was characterized by organic matter deposition during dysoxic‐suboxic to anoxic redox conditions in a fluvio‐deltaic to shallow marine depositional environment in this part of the Tethys. A low to moderate primary productivity was also prevalent during a fairly high rate of sediment accumulation. Regional correlation of positive δ13CTOC excursion during the OAE 1d throughout the Tethys and Atlantic oceans matched well, in several parts, with the current study interval that confirm the global distribution of the OAE 1d. In this region of the southern Tethys, an overall collapse of water column stratification during the OAE 1d principally related to decreased terrestrial input at low relative sea level, as evidenced from freshwater algae Pediastrum and pteridophyte spore Crybelosporites pannuceus; however, orbital forcing likely induced monsoonal activity at low‐latitudes in the SE, N, and W Tethys. [ABSTRACT FROM AUTHOR]

This study presents a high-resolution palynological analysis for the Abu Roash 'A' Member in the hydrocarbon-rich Abu Gharadig Basin, North Western Desert, Egypt. Thirty-one rock samples, spanning the upper Coniacian to lower Campanian Abu Roash 'A' Member (180 m) from the Badr El Din (BED) 2-3 borehole, were investigated. Highly diverse and well-preserved assemblages of organic-walled dinoflagellate cysts were recorded. A total of 220 species belonging to 123 genera were identified from different levels throughout the studied succession. The marine dinoflagellate cysts represented herein by 160 species allowed three palynological assemblage zones to be recognised. These include the Satyrodinium haumuriense-Isabelidinium belfastense-Odontochitina operculata Assemblage Zone (early Campanian), Dinogymnium acuminatum-Nelsoniella aceras-Odontochitina porifera Assemblage Zone (Santonian), and Cyclonephelium filoreticulatum-Spinidinium echinoideum Assemblage Zone (late Coniacian). Approximately 17 species representing 14 dinoflagellate cyst genera are identified for the first time in the Cretaceous record of Egypt. A comparison to published palynological data from neighbouring areas reveals that several significant events are synchronous throughout the Western Desert, suggesting a common similarity of water masses. Palynofacies and palynomorph analyses of the whole samples led us to define two palynofacies assemblages, which indicate that the Abu Roash 'A' Member was deposited during a successive oscillation of sea level from distal inner to middle neritic conditions. A sequence stratigraphic framework assessment was carried out to trace the relative response of the sedimentological organic matter distribution to the changes of sea level. Four third-order transgressive–regressive sequences (SQ2–SQ5) and two incomplete transgressive–regressive sequences (SQ1 and SQ6) are constructed through the Abu Roash 'A' Member. [ABSTRACT FROM AUTHOR]

The present palynological study of the Cretaceous succession in the Drazia-1 Well has been performed on 140 cutting samples covering the Barremian to Maastrichtian interval. This study yielded 33 species of spores, 16 of gymnosperm pollen grains, 14 angiosperm pollen grains and 26 dinoflagellate cysts. Based on the quantitative and qualitative palynological analyses carried out in the studied interval, 12 informal palynozones are proposed for the succession. Eight palynofacies assemblages are differentiated based on the qualitative and quantitative analyses of particulate organic matter. Khoman, Abu Roash, and middle part of Kharita formations are characterized by kerogen type II (oil prone), while the Bahariya, lowermost part of Kharita, Dahab, Alamein, and Alam El Bueib formations show kerogen type II–III (oil to gas prone). Meanwhile the upper and lower parts of Kharita Formation display type III-IV kerogen (gas to inert material). Six depositional environments are interpreted throughout the studied succession. [ABSTRACT FROM AUTHOR]

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The multiplicity of dinoflagellate cyst biozones in Cretaceous rocks limits their correlation applications, and the variations in the scientific bases of such zonations complicates age determinations and limits the validity of reliable inter-basinal correlations. The present work provides a useful summary of the dinoflagellate cyst occurrence data in Egypt and a proposed working Egyptian biozonation scheme for the area. The most diagnostic dinoflagellate cyst bioevents, in a definite time interval which occurs widely in most of the studied Egyptian, North African and Tethyan sections, are selected to be marker taxa for the erected zones. The eastern Canadian and northern European data consistently show much higher range tops for the dinoflagellate cysts at those high latitudes. The comparison and correlation of the contemporaneous dinoflagellate cyst range tops from Egypt and geographically neighbouring North African areas are vital for selecting widely distributed marker taxa and testing their validity and applicability to intercontinental correlations in the Tethyan Realm. Based on 29 wells located across Northern Egypt, this work provides a potentially useful scheme that unifies the different previously established dinoflagellate cyst palynozonation frameworks for Cretaceous rocks. The index palyno-events represented by the last occurrence datums (LODs) of the marker dinoflagellate cyst taxa are carefully picked from palynostratigraphies established earlier and methodically, consistently used to create a new regional palynostratigraphical scheme for all of the northern Egyptian territory. Ten dinoflagellate cyst interval zones were identified and described; these are, in descending stratigraphic order from youngest to oldest, Dinogymnium acuminatum (Maastrichtian–Campanian), Odontochitina operculata (Santonian–Coniacian), Cyclonephelium vannophorum (Turonian), Dinopterygium cladoides (late–middle Cenomanian), Coronifera oceanica (middle–early Cenomanian), Oligosphaeridium complex (late–middle Albian), Subtilisphaera perlucida (early Albian), Cribroperidinium orthoceras or C. edwardsii (Aptian–late Barremian), Muderongia simplex or Pesudoceratium anaphrissum (Barremian–late Hauterivian) and Systematophora silybum (Hauterivian–Berriasian). [ABSTRACT FROM AUTHOR]

The multiple biozonal nomenclatures given for the same time segment at different locations in northern Egypt are problematic, as such multiplicity is highly confusing and considerably limits the correlative value of these nomenclatures within the Egyptian territory, in the Elaterates phytogeoprovince and in the Tethyan Realm. Thirty-one wells are selected and used in this work to establish a standard and unified, semi-formal, generalised Egyptian sporomorph palynozonation scheme for northern Egypt. Marker taxa are carefully picked and tracked from the different previously established palynostratigraphies, and they are methodically re-used in the present unified framework on a regular basis, where their first down-hole appearance [last appearance datum (LAD)] palynoevents are utilised to erect a regional palynostratigraphical scheme. Ten sporomorph interval zones (IZ) and two subzones are reconstructed, established and palynologically specified from all of the studied wells. The authors surveyed the palynofloral assemblages characterising different areas of the world in order to derive meaningful palaeobiogeographical implications. Connecting these databases furnishes a comprehensive palynostratigraphical framework for inter-continental correlations with the Egyptian assemblages. In addition, such correlations confirm the dating acquired from the recovered palynological markers and assemblages presented in the current review. Comparisons of coeval assemblages confirm that the extensions and boundary limits of the palaeoprovinces of the recorded sporomorphs exhibited a gradual change and that their areal extent evolved with time. Due to the wide geographical occurrences of the recorded marker taxa during the pre-Albian stages of North and West Africa, western Atlantic and east South America, the proposed sporomorph zones can be confidently applied in these areas. During the Albian–Cenomanian such correlations can be applied only between North and West Africa and east South America. [ABSTRACT FROM AUTHOR]

Abstract This work presents the first discovery of reworked palynomorphs in Cretaceous deposits of the Gulf of Suez, Egypt. Our examination of palynomorphs contained within the productive Raha Formation reveals a distinctive record of reworked palynomorphs of Late Palaeozoic age. As provenance indicators, these reworked palynomorphs could provide clues to the stratigraphic rock units exposed during the Cretaceous at the time of deposition of the Raha Formation. Highlights • This contribution from Egypt shows a reworking palynoevent. • First record of reworked Palaeozoic palynomorphs in Cretaceous deposits, Gulf of Suez. • A prominent occurrence of reworked Late Palaeozoic sporomorphs in Raha Formation. [ABSTRACT FROM AUTHOR]

The current investigation provides further insight into the petroliferous characteristics of the Abu Roash “G” Member, which is regarded as an important rock unit for the Egyptian oil industry. Forty-seven samples covering the “G” Member were selected from the BED 14-1 and BED 2-4 wells in the Abu Gharadig Basin and from the Abu Tunis 1X well in the Matruh Basin, both of which are located in the north Western Desert. An independent dating of the “G” rocks of BED 2-4 by benthic foraminifera and ostracods, in addition to palynological dating, suggests a middle-late Cenomanian age and provides the biochronostratigraphic framework for the sequence stratigraphic analysis. Analysis of the vertical distribution of particulate organic matter defines three palynofacies types (PF). PF-1 represents the basal “G”, where shales of the BED wells and calcareous shale of Abu Tunis 1X were deposited during a relative sea level rise in an outer middle shelf environment that experienced a notable high primary productivity. Prevailing reducing (suboxic-anoxic) conditions supported preservation of very high amounts of amorphous organic matter (AOM) in PF-1. PF-2 is equated to shales of the middle “G” of BED 14-1 and BED 2-4 and to calcareous shales and limestone of the upper “G” in Abu Tunis 1X. PF-2 was deposited during a relative sea level fall in an inner middle shelf setting under better-developed suboxic-anoxic conditions. PF-3 corresponds to the upper “G” of BED 14-1 and BED 2-4 and represents the shallowest setting, where sandy and silty shales were deposited during a pronounced sea level fall in an inner shelf environment. The same suboxic-anoxic conditions were prevailing during deposition of PF-3. Three bioevents were recorded, which could be of palaeoecological and/or biostratigraphic significance. These are Senegalinium aenigmaticum-Dinopterygium cladoides peak, Dinopterygium cladoides - Dinopterygium alatum peak, and an acme of Classopollis brasiliensis . Sequence stratigraphy of a transect of the four studied sections was carried out to understand the response of the particulate organic matter distribution and depositional system to the sea level changes. Three third-order, depositional genetic sequences were recognized and correlated with the global sea level curve (KCe 2, KCe 3, and KCe 4). The early highstand systems tract (eHST) of the genetically related KCe 3 in all wells is characterized by relatively rich organic matter, where combined remarkably low water circulation and insignificant dilution of organic matter with coarse terrigenous material probably supported good preservation of organic matter. Spatial distribution of the “G” rocks shows lateral facies changes. This was inferred from sedimentation of an organic-poor (avg. 0.8 TOC wt %), coarse clastic (sandy shales) facies in the studied area in Abu Gharadig Basin. Sedimentation changes laterally into a northeast and northwest organic-rich, finer clastic (shale, calcareous shales, and argillaceous limestone) facies in the western Matruh Basin. The robust anoxic conditions and very low dilution of organic matter by terrigenous influx enhanced the organic richness (avg. 2.4 TOC wt %) of these rocks, which resulted in the formation of promising hydrocarbon source rocks. Thus, for a successful hydrocarbon exploration in the north Western Desert, the promising source section of the “G” Member would be associated with shales, calcareous shales, and argillaceous limestone lithologies. Its depositional environment is mainly confined to outer middle and inner middle shelf settings that have widespread suboxic-anoxic conditions and show eHST pattern. In contrast, the regressive intervals that are denoted by the lowstand systems tract (LST) and/or the late HST (lHST) typify the relatively coarse clastics as good quality reservoir rocks that are characterized by poor organic richness due to dilution with terrigenous influx. [ABSTRACT FROM AUTHOR]

Thirty-eight cutting samples from the Lower Jurassic to the Upper Cretaceous succession of the Abu Tunis-1X well, north Western Desert of Egypt, were processed palynologically to extract their psilate sporomorphs. This designated practice was made to assess the digitally-quantified progressive changes in the triple Red-Green-Blue (RGB) coloration of sporomorph exine with depth. Stabilization and calibration of the illumination system was applied. Certain precautions were also implemented prior to such digital RGB measurements; for example, some exceptionally lighter (caved) or darker (reworked) specimens were excluded from RGB coloration population samples to avoid misleading results. A minimum of three and up to ten spore grains were studied according to the sample richness and two RGB readings were taken for each selected specimen. The average, standard deviation, and confidence level values for each sample were calculated due to the variable palynological productivity of the samples. In the present study, an attempt was made to monitor and distinguish which of the color components and/or parameters is the most sensitive detector of the progressive maturation changes with depth. By investigating the trends of different parameters of the RGB (i.e. total RGB, R, G, B, R/G) with depth, we were able to distinguish and deduce a linear maturation index from the triple RGB readings. Such a linear maturation index was based on the R component and was successfully correlated and calibrated with other conventional, linear maturity indices (T max ° C, vitrinite reflectance-VRo%, and thermal alteration index-TAI). The newly modified, RGB-based maturation index called the Kerogen Maturity Index (KMI) can confidently and effectively detect the subtle and progressive changes in kerogen maturation with depth. Such correlation and calibration practices presented herein enabled us to present a modern, reliable, easy to use, and inexpensive measuring technique to assess the thermal maturity of organic matter. The KMI covers the immature and most of the mature phases (early-upper mature) of kerogen and it has its own vitrinite-calibrated cut-offs, which can be correlated with both the T max and TAI parameters. This undoubtedly allows the KMI to be easily correlated and complement other classical, expensive maturity indices. This opens the door widely for the palynologists and organic petrologists to use the KMI with good confidence and high reliability for its proven good maturity appraisal. [ABSTRACT FROM AUTHOR]

The present study shows the advantage of the palynostratigraphy and paleoenvironmental inferences concepts in subdividing and interpreting the depositional environment of the Jurassic rocks, depending on two sections in two boreholes drilled in the Darag Basin, Egypt. Six Jurassic rock units representing the mixed siliciclastic and carbonate sediments were recognized from top to base; the Tauriat, Arousiah, Kehailia, Safa, Shusha and Rajabiah formations. The palynomorph assemblage associated with moderately diversified dinoflagellate cysts and fewer sporomorphs, show poor to fair preservation. About 20 dinoflagellate cysts, 8 pollen, and 3 pteridophytic spore species have been recorded. The Jurassic rocks are originated from the late Jurassic (early Oxfordian) and early (Toarcian - Aaleneian) based on the recovered marker taxa. The studied sections are differentiated into six biozones, Systematophora sp. (Callovian-Oxfordian), Gonyaulacysta jurassica (Callovian), Dichadogonyaulax sellwoodii (Late Bathonian), Sentusidinium sp. (Early Bathonian), Pareodinia ceratophora (Bajocian) and Psilate spores , Classopollis and Sphaeripollenites Acme Zone (Toarcian-Aalenian). According to the Particulate Organic Matter (POM) composition in the studied wells, the palynofacies assemblages led to identifying three depositional settings, the palynofacies −1 (PFA-1), which is characterized by opaque phytoclasts and high volume of spores and pollen grains was deposited in a marginal shallow-marine environment during a relative sea-level fall. The PFA-2 is composed of brown phytoclasts, moderate Amorphous Organic Matter (AOM) with pollen grains and dominated dinocysts. It was deposited during a slight sea level rise in a proximal inner neritic environment. Simultaneously, the PFA-3, which was dominated by AOM and dinoflagellate cysts with moderate brown phytoclast content, was deposited as a distal inner neritic environment during a relatively high relative sea level. • Jurassic sections of two boreholes in Darag Basin of Egypt were studied palynologically. • The lower and upper Jurassic successions were distinguished. • Six biozones were identified in the studied interval. • Three depositional settings were explained based on different three palynofacies assemblages. [ABSTRACT FROM AUTHOR]

A palynological study of 35 cutting samples from the Middle Jurassic–Lower Cretaceous section encountered in the OBA D-8 Well in the north Western Desert of Egypt yielded palynomorphs and particulate organic matter used to interpret the biostratigraphy, palynofacies, paleoenvironment, thermal maturation, and hydrocarbon potential of the Matruh Basin. The stratigraphically significant dinoflagellate cyst and sporomorph taxa recovered, which include Murospora florida , Aequitriradites spinulosus, Pilosisporites trichopapillosus , Callialasporites trilobatus , Tenua anaphrissa , Muderongia simplex , Systematophora sp., Gonyaulacysta jurassica , Korystocysta gochtii , Pareodinia ceratophora , and Dissiliodinium sp., permit an age assignment of the studied section as Bajocian to Aptian. Seven formal dinoflagellate cyst zones and four formal sporomorph zones are proposed for this time interval, in addition to differentiating four palynofacies assemblages and using the Rock-Eval Pyrolysis method to visually and geochemically evaluate the source rock potential. The 0.45–2.82 wt% TOC values of the studied samples indicate fair to good source rocks. An inner neritic depositional environment due to relatively high sea level is deduced for the Khatatba and Masajid formations using palynological proxies, as reflected in the lower percentages of sporomorphs relative to dinoflagellate cysts. During the Lower Cretaceous, a predominance of terrestrial sporomorphs in the Alam-El Bueib Formation suggests the advance of a fluvio-deltaic environment, possibly related to a significant sea level fall and regressive phase. • The studied Bajocian- Aptian succession is divided into interval biozones. • The interval zones are based on the first downhole appearances of the zonal taxa. • Seven dioflagellate cyst biozones matched with four sporomorph biozones were established. • Four palynofacies assemblages are differentiated. • Source rock potential is evaluated visually as well as geochemically by Pyrolysis Rock-Eval method. [ABSTRACT FROM AUTHOR]

Two hundred and seventy four samples, covered the Bahariya sections encountered in 13 boreholes, drilled in three main fields of the General Petroleum Company concession, Abu Gharadig Basin, north Western Desert, were critically investigated for their palynomorphs content. A standard acid-based palynological processing technique is employed to extract the palynomorphs. Fair to moderate diversity and moderate to good preserved palynomorph assemblage has been recovered. This study yielded 107 species of spores, pollen grains and dinoflagellate cysts. Six remarkable successive first downhole appearance (FDA) sporomorph-events are defined and biostratigraphically utilized for dividing the Bahariya Formation and delineating the Bahariya/Kharita contact. The upper Bahriya unit includes the first Afropollis jardinus event dated latest early Cenomanian, while the middle Bahriya unit comprises the second Elatersporites klaszii event dated early Cenomanian. The lower Bahriya unit, dated early Cenomanian-late Albian, contains the third, fourth, and fifth Cretaceieporites densimurus , Trilobosporites laevigatus and Stellatopollis sp. events, respectively. The contact between Bahriya Formation and the upper part of the underlying Kharita Formation, dated early-middle Albian, is placed on Concavisimisporites punctatus event. The authors found the possibility of these six zones to be widely traced and provide potential bio-correlation tool for the Bahariya sections in Abu Gharadig Basin. According to the presence or absence of such six successive events and their average zonal thicknesses, the intra-formational disconformities and positions of the faults could be allocated with confidence. The remarkable thinning in the thickness of such zones could localize the position of disconformities caused by non deposition or erosion/faulting within the Bahariya sections. The aforementioned six events could be correlated and nicely matched with their equivalent six log-based cycles on the log responses. The authors encourage the Egyptian industrial geologists to follow the presented successive six sporomorph-events in the future palynological-steering exploration and production activities in the Bahariya rock unit and effectively utilize such events as intra- and inter-basinal dating tool and possible correlation control for the Bahariya sections across the northern basins of Egypt. • 13 boreholes in GPC concession, Abu Gharadig Basin, were palynologically investigated. • Six successive sporomorph-events are defined and utilized for dividing the Bahariya and delineating Bahariya/Kharita contact. • The presence/absence of such events and thinning in the thicknesses of biozones allocated disconformities. • The six events could be matched with their equivalent log-based cycles on the log responses. • These sporomorph-events are utilized for intra- and inter-basinal correlation for Bahariya. [ABSTRACT FROM AUTHOR]

The Campanian-Maastrictian black shales in Egypt comprise a significant part of the worldwide belt of organic-rich shales. These dark-colored shales stretch from the Dakhla in the Western Desert to Safaga area in the east along the Red Sea and are well known in the Middle East and North Africa. A palynological study of these shales hosted mostly in the Duwi and Dakhla formations yields a Campanian to Maastrichtian age. The extracted palynomorph assemblage from the Abu Tartur and Quseir boreholes, which is dominated by dinoflagellate cysts (dinocysts) representing a well-preserved peridinioid association (>90% of the total dinocysts), is indicative of marine origin and very high paleoproductivity. The common dinocysts are Andalusiella mauthei, Andalusiella gabonensis, Cerodinium diebelii, Senegalinium bicavatum, Senegalinium laevigatum, Palaeocystodinium golzowense and Palaeocystodinium australinum. This assemblage is comparable with the dinoflagellate cyst records of the Campanian-Maastrichtian low latitude strata in northwest Africa (Morocco and Tunisia) and southern Europe. The dinocyst distribution in the Abu Tartur and Quseir borehole sections suggests an isochronous signature during the early Maastrichtian age. • Peridiniacean dinocysts are recovered from the studied intervals. • The cored Duwi-Dakhla in Egypt yielded marine assemblage from the Abu Tartur and Quseir sections. • Correlatable dinocyst signatures across the belt of organic-rich shales are detected. [ABSTRACT FROM AUTHOR]

A recent study of selected samples from the Cretaceous (Albian) Kharita Formation of Egypt revealed very good to excellent source rock (SR) potential for six intraformational, organic-rich intervals. This work investigates the SR potential of the entire Kharita Formation across the Matruh Basin, using samples from two wells: the Abu Tunis 1X well from the central part of the basin, and the Siqeifa 1X well drilled on the eastern margin of the basin. More strongly reducing conditions were developed in the centre of the basin, and resulted in the deposition of more organic-rich shales by comparison to the less reducing conditions that prevailed on the eastern basin margin, where the shales contain less organic matter. Deltaic intraformational shales and carbonates in the Kharita Formation of Abu Tunis 1X constitute a significant 120 m net of the potential SR. The lower Kharita Formation contains 34 m net shale SR of good to very good/excellent organic richness, yielding values of 1.14–11.59 wt % total organic carbon (TOC). The organic matter has low Hydrogen Index (HI) values (184–389 mg HC/g TOC) and amorphous organic matter (AOM) and relatively high non-opaque phytoclast frequencies indicating mainly gas/oil-prone organofacies (kerogen Types III/II). The upper Kharita is rather important, containing 86 m net shale/carbonate SR that has fair to good organic richness (0.8–1.8 wt % TOC), and lower HI (126–250 mg HC/g TOC), a dominance of non-opaque phytoclasts, and subordinate AOM frequencies, which together indicate gas/oil-prone organofacies (kerogen III/II). In the Siqeifa 1X well, Kharita deltaic intraformational shales and shaley dolostones comprise 80 m net SR, which has mainly fair to good to less very good organic richness (0.8–2.1 wt % TOC), whilst low HI (93–220 mg HC/g TOC), dominance of non-opaque phytoclasts and subordinate AOM indicate gas-prone organofacies (kerogen Type III). A relative upward increase in deposition of lignite and coaly carbonaceous material supports a gas-prone organofacies. Whilst thermal maturity indices only point to immature to early mature (pre- to early oil-window) SRs in both the Abu Tunis 1X and Siqeifa 1X wells, hydrocarbon exploration focussing on this potential source rock may be justified in areas to the southeast of the Matruh Basin, where modelling indicates this unit may have reached the late mature oil- to main gas-generation windows. • Intrabasinal variation in lithofacies, organic facies/richness, and organic quality are documented for the Cretaceous Kharita Formation of the Matruh Basin, Egypt. • Reducing conditions at the depocentre led to deposition of organic-rich gas/oil-prone deltaic shales in the lower Kharita Formation. • Oxic conditions at the basin margin led to deposition of organic-lean gas-prone deltaic shales in Kharita Formation. • Reflectance and Rock-Eval data indicate immature to marginally mature source rocks in both the basin centre and marginal areas. • As the southeastern part of the Matruh Basin is known to have reached thermal maturity, the Kharita Formation should be a suitable exploration target. [ABSTRACT FROM AUTHOR]

During the past decades, exploration activities carried out in the Western Desert of Egypt by several oil companies revealed the oversimplified approach to the study of sedimentary basins in this region. The current study evaluates and discusses the palynology and palynofacies of the clastic succession of the Kharita Formation (Albian) in one of the most petroliferous, deep seated, fault controlled basins in the Western Desert of Egypt, the Abu Gharadig Basin. Although the focus is on the palynofacies association, the hydrocarbon potential of the Kharita Formation will also be addressed by means of organic petrology and Rock-Eval pyrolysis. Marine Cretaceous source rocks have generated substantial quantities of oil and gas in the Abu Gharadig rift Basin. Moreover, Abu Gharadig Basin is characterized by containing not only oil/gas generating source rocks but also reservoir rocks with appreciable porosities and permeabilities. Palynological, TOC/Rock-Eval pyrolysis, and vitrinite reflectance (VR o %) data from 26 cuttings samples recovered from the Kharita Formation in the BED 2-1× well, are presented. The palynological age dating (AL-2 Palynozone) confirmed early to middle Albian age based on the first downhole appearance of the marker Concavisimisporites punctatus. The optical and visual characterization of the palynofacies associations showed two distinct palynofacies associations that alternated with each other. Kerogen type III to III/II was recorded based on the dominance of phytoclasts and opaque organics. Some intervals showed a slight dominance of amorphous organic matter (AOM). Thermal Alteration Index (TAI) values of 2+/3-measured on the psilate trilete spores, in combination with vitrinite reflectance (VRo) values in the range from 0.51 to 0.62%, and the yellow to dull-yellow colors of the liptinite macerals exhibited under UV light excitation indicate immature to the early stage of the oil window. Tmax values from Rock-Eval pyrolysis range from 426 to 438 °C also confirm the low maturity of the organic matter. Thin coal stringers were recorded within the Kharita Formation having slightly higher VRo,ran values (0.64 to 0.76%), which is possibly the result of differences in mineral matrix variations within the Kharita Formation. Based on the low TOC (avg. 0.71 wt%), S 2 (avg. 0.97 mg HC/g rock), and HI (avg. 149 mg HC/g TOC) values from pyrolysis, the hydrocarbon potential of the Kharita Formation in the studied well is considered to be low. • Palynological age dating confirmed early-middle Albian age for the Kharita Formation. • Two distinct and alternating palynofacies associations were revealed. • Reflectance and Rock-Eval data indicate marginally mature to early mature matter. • Thin coal seams and coaly stringers have higher Ro. • Hydrocarbon potential of the Kharita in the studied well is low. [ABSTRACT FROM AUTHOR]

The beginning of the Late Cretaceous (Cenomanian) attested to a major marine transgression interrupted by sea level falls in north Africa, which led to significant environmental perturbation and widespread accumulation of organic matter-rich sediments. During this period, northern Egypt was located at the southern edge of the Tethys Ocean and deposition of thick siliciclastic alternations between shales, siltstones, and sandstones of the Bahariya Formation took place in the BED2 gas field of the Abu Gharadig Basin, north Western Desert. An integrated approach of palynofacies analysis and palynomorph composition, organic petrography, and geochemical analysis of total organic carbon (TOC)/Rock-Eval pyrolysis, carbonate content, XRD analysis, and clay mineralogy of thirty-nine cutting samples obtained from the lower-middle Cenomanian Bahariya Formation was conducted. This approach was used to characterize organic matter and possible occurrence of source rock intervals, paleoenvironmental and paleoclimatic conditions and their role in organic matter accumulation. Moderate to high proportions of pteridophyte and water fern spores and pollen grains of Araucariaceae (Araucariacites), Cheirolepidiaceae (mainly Classopollis), and Gnetalean (Elaterate pollen) and Afropollis versus the sparsely recorded xerophilous ephedroids (Ephedripites) indicate prevalent conditions of a warm and humid climate. This is consistent with clay mineral composition that is dominated mainly by kaolinite and smectite compared to low illite and the lack of chlorite, which indicated a predominantly warm-humid climate state. Palynofacies analysis showed two assemblages; the first one is dominated by phytoclasts and indicates gas-prone Type III kerogen and deposition in a fluvio-deltaic environment. The second palynofacies assemblage is characterized by moderate abundance of phytoclasts and AOM mostly of terrestrial origin, suggesting a mixed Type III/II kerogen and deposition in a marginal to shallow neritic shelf environment. The organic geochemical characterization showed relatively low average values of TOC, S 2 , and HI, indicating that the Bahariya Formation is characterized by Type III gas-prone kerogen. Thermal maturity of the Bahariya Formation ranges from immature to the early stage of the oil window. Additionally, organic matter characteristics of the Bahariya Formation are qualitatively and quantitatively similar to their equivalents from nearby basins. Low TOC contents are attributed to a high sedimentation rate and an increased terrestrial input of sand- and silt-sized fractions at shallow water column settings that controlled strong dilution and decomposition versus low burial efficiency of the organic matter. • Cenomanian Bahariya Formation was studied using palynology, geochemistry and organic petrography. • Spores and pollen confirmed a warm-humid climate during the Cenomanian in this part of the southern Tethys. • The Bahariya Formation has poor source rock potential, but the lower intervals show very good potential. • Organic matter assessment is characterized mainly by type III gas-prone kerogen. • T max and VRo indicate immature to early mature oil window consistent with spore color analysis. [ABSTRACT FROM AUTHOR]

The Early Cretaceous (Albian) was a time of equatorial to polar temperature warming and increased environmental perturbations of the global carbon cycle and oceanic anoxia, which resulted in the widespread accumulation of organic carbon-rich sediments. During the Albian, the southern margin of the Tethys Ocean was characterized by marginal to shallow water conditions with minor phases of enhanced stratification and bottom water anoxia in northern Egypt. At this time, accumulation of the thick siliciclastic succession of sandstones versus shale intercalations of the Kharita Formation took place in the Abu Gharadig Basin. The Kharita Formation is investigated for palynological composition and palynofacies analysis, organic matter characterization, hydrocarbon generation potential, and thermal maturity assessment based on 30 and 26 drill cuttings samples from the BED2-3 and BED2-1x wells, respectively. A rich palynological assemblage of herbaceous hygrophilous plants, including pteridophyte spores and water ferns, along with Elaterates and Afropollis pollen indicated warm humid climate conditions. Furthermore, abundant occurrences of Araucariaceae and Cheirolepidiaceae, including Araucariacites , Inaperturopollenites , and Classopollis , reinforcing warm climatic conditions and their climax in areas near coastal vegetation. Statistical cluster analysis identified two palynofacies assemblages (PFA) based on stratigraphic variation in the particulate organic matter (POM). The PFA-1 characterized all samples of the BED2-3 and some intervals of the BED2-1x wells and comprised moderate abundances of phytoclasts and amorphous organic matter (AOM) that defined a kerogen Type II, whereas the PFA-2 was recorded only in the BED2-1x well and is dominated by phytoclast fragments of kerogen Type III. The geochemical screening revealed, based on the low average values of TOC (1.2 wt%), S 2 (1.8 mg HC/g rock), and HI (146 mg HC/g TOC), that the Kharita Formation is characterized by a kerogen Type III of gas-prone hydrocarbon but with low generation potential. T max and vitrinite reflectance measurements along with greenish-to golden-yellow liptinite macerals indicated that the thermal maturity of preserved organic matter is still in the immature to the early mature stage of the oil window. Inconsistency in kerogen types between PFA-1 and geochemical deductions was interpreted in terms of microscopic investigations of the recovered AOM. Morphologic characteristics observed that most AOM particles were of terrigenous origin due to the impact of biodegradation and transformation of phytoclast particles into AOM, confirming a kerogen Type III of gas-prone hydrocarbons instead of Type II that was elucidated by palynofacies ternary diagrams. The occurrence of coaly matter in the BED2-1x infers closer proximity to fluvio-deltaic sources during deposition of the lower part of the Kharita Formation than in the BED2-3. • Albian Kharita Formation was investigated based on palynology, geochemistry and organic petrography. • The Kharita Formation has poor to good source rock potential, but few intervals show very good to excellent potential. • Organic matter is characterized by gas-prone type III kerogen according to palynofacies analysis and Rock-Eval HI values. • Organic matter is in the immature to early mature oil window based on spore color analysis, T max and VRo values. [ABSTRACT FROM AUTHOR]

Borehole image logs are used to overcome the lack of core samples and other conventional open-hole logs in many subsurface reservoirs around the world, significantly reducing the likelihood of petroleum resource exploration. These image logs can provide high-resolution data to visualize sedimentary structures, facies types, lithofacies, geomechanical characteristics, and depositional trends. Sedimentologists recognize the Bahariya Formation of the North-Western Desert of Egypt as the typical coastal -shallow marine depositional model that emphasizes a typical heterogeneous sandstone reservoir with many obstacles in production profile. One of the most significant issues related to the heterogeneous Bahariya reservoir that confronts hydrocarbon producers is the loss of productive target zones due to spatial facies changes. This research aims to overcome the exploration and development challenges of the complex and heterogeneous sandstone reservoir of the Albian – Cenomanian Bahariya Formation that lies in the Abu Gharadig Basin, Southern Tyths, Egypt. In this work, we used integrated image logging in conjunction with palynofacies, core samples, and sequence stratigraphy to provide high resolution information that can aid in better resource exploitation. Furthermore, we utilized the integrated work in the definition of the high-resolution para-sequences, sequences boundaries, lithofacies characteristics and paleocurrent analysis of each facies association. The interpretation of coastal shallow marine facies from four BHI-logs was established and calibrated with two core sets in order to define the best hydrocarbon reservoir intervals and focus on improving the development plan of the study area. Our findings show that the Bahariya Formation is characterized by eleven facies associations which have been interpreted based on the integrating of the twenty-seven electrofacies extracted from the FMI images, wireline logs, and core photographs. The identified facies associations were classified into five depositional sequences and their boundaries were determined using dipmeter patterns and extracted lithofacies from BHI. The LST and MFS deposits in both the fourth and fifth depositional cycles, respectively, whereas the HST deposits are found only in the third depositional cycle. According to our findings, the development of the shoreface sandy facies of cycles three and five represents the maximum rate of sea-level rise, as well as the development of the offshore sand bar system, which represents high-quality sandstone reservoirs. This case study demonstrates how image logs can be used to better understand the spatial distribution and geometries of sandstone bodies in the Bahariya Formation. Furthermore, it provides a reference imaging fingerprint of high-resolution coastal shallow marine, high-frequency sequences analysis, sedimentary structures, and extracted electrofacies analogues that can be used in the basin and elsewhere. • Five high resolution depositional cycles are defined with numerous para-sequences. • Eleven facies associations are defined within the Bahariya Formation based on 27 FMI-electrofacies. • The Bahariya Formation is influenced by sea level fluctuations that result in reservoir complexity. • The study provides a reference imaging fingerprint of high-resolution shallow marine sediments. • High-resolution image logging help in reconstructing the basin depositional settings. [ABSTRACT FROM AUTHOR]

The palynological and biostratigraphical studies have been carried out on 59 subsurface cutting samples from three formations (Khoman, Apollonia and Dabaa) represent the Santonian-Oligocene succession of the Drazia-1 well in East Yidma oil field (north Western Desert, Egypt). A total of 115 dinoflagellate cysts species have been identified and utilized in distinguishing five interval dinoflagellate cyst zones for the first time in the Western Desert from old to young: 1) Odontochitina operculata (Santonian-Campanian), 2) Cerodinium diebelii (Maastrichtian), 3) Danea californica (Danian-Selandian), 4) Apectodinium homomorphum (Thanetian–Bartonian), and 5) Deflandrea phosphoritica (Priabonian-Chattian). The established palynozones have been correlated with equivalent Late Cretaceous-Paleogene dinocyst biozones in Egypt and worldwide. • First biostratigraphical results for the Santonian-Oligocene succession of the Drazia-1 well in North Western Desert of Egypt. • Five dinoflagellate cyst biozones have been recognized. • The identified biozones are important in age dating of Late Cretaceous-early Oligocene successions in Western Desert of Egypt. [ABSTRACT FROM AUTHOR]

The depositional phases of the Nile Delta are investigated based on the palynofacies and geochemical analyses in samples from two studied wells Baltim-1 and NDOB-1 wells. These depositional phases determine the ability to produce and preserve the organic carbon. The Nile Delta's hydrocarbon system is based mainly on the Neogene rocks, particularly those ranging from the Late Miocene to the Pleistocene, where environmental conditions governed organic matter accumulation. The depositional history in this region is related to the activity of sediment input by the different phases of the Nile River and their ability to transfer the sediments and terrigenous organic matter. Multivariate statistical analyses of the palynofacies revealed four types, namely distal-high oxic type A, proximal-suboxic type B, proximal-dysoxic type C, and distal-oxic type D. In addition, proximal-distal and oxygen depletion trends were identified based on the values of the principal components analysis (axis 1). The characterization of the palynofacies types incorporated inorganic geochemical analysis of trace elements to determine environmental gradients, were compared to the values of organic matter (0.27–1.18 wt% TOC). Organic matter concentrations were low during most depositional phases despite the active influx of the terrigenous organic matter and the productivity of marine organic matter. These results can be attributed to the Nile Delta region's depositional phases identified from the palynofacies types and major element oxides. It is inferred that the Nile River delivered a high rate of sediments into the basin, in addition to nutritious material that increased the sea surface paleoproductivity of marine organic matter. However, the high sedimentation rate during the different depositional phases did not attain the optimum threshold to preserve organic carbon in high concentrations. • Distribution of Hydrocarbon source rocks Neogene Section from Nile Delta is studied. • The study is based on palynofacies and inorganic geochemistry. • The study revealed proximal-distal and oxygen depletion trends in the studied section. • Organic matter quality and quantity are deposited in oxic to dysoxic conditions. • Composition of organic matter is greatly influenced by terrigenous input. [ABSTRACT FROM AUTHOR]

Neogene succession in the offshore Nile Delta region is essential to the hydrocarbon petroleum system. Up to date, little is known about the nature and distribution of organic matter and its potential to generate hydrocarbon. This potential is tested through extensive palynofacies and organic geochemical analyses in a new approach in this region. Based on the palynofacies analysis, the samples from NDOB-1 and Baltim-1wells are discriminated into four types using the statistical application of cluster and principal component analyses. These four types are distal-High Oxic type A, proximal-suboxic type B, proximal-dysoxic type C, and distal-oxic type D. In addition, the analysis leads to identifying the proximal-distal and oxygen depletion trends based on the values of the principal component analysis (axis 1). This palynofacies analysis is used as an environmental framework for hydrocarbon source rock evaluation. This evaluation is integrated with the organic geochemical parameters by pyrolysis (Rock-Eval and gas chromatography) and spectroscopic (Fourier Transform Infrared) methods. This study reveals that the dominant kerogen types are IV (inert) and III (gas-prone) which are remarked by the opaque and brown translucent phytoclasts palynofacies types A and D, respectively. Kerogen type II is presented in a minor abundance in palynofacies types B and C that are distinguished with AOM. However, kerogen type II organic matter is much diluted with kerogen type IV and III, leading to poor to fair organic geochemical quality (S 2 and hydrogen index). Both wells' maturity levels are detected within the Kafr El Shiekh Formation. Nevertheless, the poor hydrocarbon source rock quality becomes important if considered with the volume and thickness of the Neogene sediment, as indicated by the source potential index that has a cumulative value of 2.5 t HC/m2 in NDOB-1 well and 2.8 t HC/m2in Baltim-1 well. These values are comparable to some of the prolific hydrocarbon fields in other places. • Distribution of Hydrocarbon source rocks in Neogene Section from Nile Delta is studied. • The study revealed proximal-distal and oxygen depletion trends in the studied section. • Organic matter quality and quantity indicate deposition in oxic & dysoxic conditions. • Composition of organic matter is greatly influenced by terrigenous input. • The quantity of the organic matter is diluted by high sedimentation rates. [ABSTRACT FROM AUTHOR]

This paper discusses the hydrocarbon potential of the Jurassic succession in a mature basin in Egypt as an important element of a larger petroleum system study. Prior to any organic petrographic and organic geochemical analyses, a palynological age dating of the originally undifferentiated Jurassic sequence was carried out to identify different formations under investigation. This was based on key bioevents of some recovered dinoflagellate cysts and the identified lithology. Palynological, TOC/Rock Eval pyrolysis (including modified Rock-Eval methods), and vitrinite reflectance (VRo%) data from a total of 14 samples taken from the uppermost lower-upper Jurassic sequence represented by the Wadi Natrun (Toarcian-Aalenian), Khatatba (late Bathonian-Callovian), and Masajid (Oxfordian) formations in the Abu Tunis-1 × well, are presented. In addition, two samples from the Abu Tunis-1 × well and the proximal (~ 32 km to the east) Siqueifa-1 × well, having the highest remaining hydrocarbon potential (S2 yields), were analyzed and their results were compared using modified pyrolysis programs. Although the data showed a good correlation between the TAI of the palynomorph assemblage, vitrinite reflectance, and Tmax from Rock-Eval pyrolysis in the shallower intervals, the correlation between VRo and Tmax was poor in the lower half of the studied succession (middle Khatatba and Wadi Natrun formations). The very low Tmax values indicate immature OM while VRo and TAI indicated middle stage of oil window to past peak oil generation. The reason for this discrepancy is that the deeper samples are reservoir rocks, not source rocks, and the majority of the organic matter is not composed of reactive kerogen but consists of migrated hydrocarbons and NSO compounds. Contamination due to oil-based mud (OBM) was eliminated because the Abu Tunis-1 × well was drilled in 1969, prior to the extensive use of OBM in drilling. This study showed that a multi-proxy approach is the best way to screen the hydrocarbon potential in a thick succession that contains interbedded source and reservoir rocks. [ABSTRACT FROM AUTHOR]

The Gulf of Suez area in eastern Egypt is one of the most prospective and promising hydrocarbon provinces all over the world. Sixty drill cuttings samples of the Upper Cretaceous Raha Formation (70–120 m) have earlier been processed for their palynomorph and palynofacies contents, including 36 geochemically screened samples for their source-rock potential using TOC, Rock-Eval®. 6 Turbo, the new Rock-Eval® 7S instrument along with one of its latest modules, the CleanSim method. The combination between visual palynofacies and RGB-based sporomorph color image analysis along with the geochemical results are presented as part of a detailed assessment of the organic matter (OM) types, OM-richness, and thermal maturity levels. Palynofacies analysis defined three associations of OM types. The first and third associations consist of kerogen Type II; the former is dominated by a moderate abundance of amorphous organic matter (AOM) and phytoclasts, whilst the latter is dominated by high AOM content. Conversely, the second association is dominated by terrigenous fragments of gas-prone Type-III kerogen. The application of RGB analysis indicated a thermally immature to mature stage for some intervals in one of the three studied wells, the B-109. Geochemical screening results led to divide the Raha Formation into three distinctive groups, which are characterized by varied OM qualities and quantities, hydrocarbon potential, and thermal maturity levels. Varied thermal maturity levels was related directly to the Late Cretaceous tectonics like the effect of Syrian Arc System and the Oligocene-Miocene syn-rift activity that led to the opening of the Gulf of Suez. Differences in kerogen types were observed between geochemical and palynofacies analyses. Microscopic investigations of palynofacies-dominated AOM suggested that most AOM particles were of terrigenous origin due to the effect of biodegradation and gradual transformation of phytoclasts into AOM, reflecting a kerogen Type III instead of kerogen Type II that was indicated by palynofacies analysis ternary plots. • A modern technique, Rock-Eval 7S CleanSim method, was used to remove contaminants effects. • Integration of visual palynofacies and digital color analysis with geochemistry seems promising. • Source rock assessment of the Raha Formation defined three groups of OM Type-II to III. • T max indicates thermally immature to early mature phase that agrees with the RGB results. • Local structural activity and environmental settings influenced maturity and OM-richness. [ABSTRACT FROM AUTHOR]

Rock-Eval pyrolysis/TOC, petrographic, and geochemical data available in the public domain for a total of 296 core and 243 drill cuttings samples from the Albian-early Cenomanian Kharita and Bahariya formations of four main basins, Shushan, Abu Gharadig, Matruh and Dahab-Mireir, were reviewed. This review provides a comprehensive overview to understand the organic richness, type, and thermal maturity of potential source rock intervals within the Kharita and Bahariya formations in northern Egypt by means of burial history modeling and oil-in-place calculations. Geochemical data of both formations confirmed the presence of up to excellent source rocks of varied kerogen types but mainly of Type III (gas-prone) and mixed types II/III. Thermal maturity levels ranged from immature to the early stage of oil window, although some intervals reached the peak oil window in the Abu Gharadig and Shushan basins compared to their counterparts. The depositional paleoenvironment of the Kharita and Bahariya formations is interpreted based on the organic biomarker compounds and palynofacies associations. Generally, both formations in the four basins were interpreted to accumulate in a fluvio-deltaic to marginal marine setting, although the Kharita rock unit was slightly less marine based on the isoprenoids pristane and phytane to nC 17 and nC 18 ratios. The ratio of 22S/(22S + 22R) for the homohopanes C 31 and C 32 of Kharita oils from the Shushan Basin ranged from 0.50 to 0.60, indicating marginally mature to the onset of oil generation. However, common amongst much of the previous studies was the notable differences in organic matter contents, thermal maturity levels and hydrocarbon potential. Environmental and ecological processes, including proximity to shoreline, terrestrial/riverine input, oxygenation levels and water column conditions, are considered the primary drivers that triggered variable amounts of organic carbon accumulation. While differences in thermal maturity levels were attributed to tectonic activities and related structural processes. • Fair to good organic matter-richness in the Bahariya and up to excellent for the Kharita Formation was reported. • The source rock beds within the both formations have variable kerogen types (Type III, II/III and II). • Levels of maturation in both formations were mainly immature to early mature with minor intervals in peak stage of oil window. • The Kharita and Bahariya formations had the highest yield of oil‐in‐place in the Matruh Basin. • Despite the Kharita was less marine than Bahariya, both formations were deposited in fluvio-deltaic/marginal marine settings. [ABSTRACT FROM AUTHOR]

Geochemical and palynological proxies were determined for 31 samples representing the upper Coniacian-lowermost Campanian Abu Roash A Member, collected from the BED2-3 well. This was done to assess the prevailing paleoredox conditions, productivity levels, and water-column settings to: (1) understand controls and mechanisms related to accumulation of organic carbon within the sedimentary record; (2) assess principal environmental processes that triggered the preservation of organic matter-poor, calcareous shale and limestone facies of the Abo Roash A Member; and (3) to interpret the paleoceanographic settings and confirm the occurrence of either Oceanic Anoxic Event 3 (OAE3) or Cretaceous Oceanic Red Beds (CORBs) within the Abu Gharadig Basin in the southern part of the Tethyan Ocean, Egypt. Sedimentation rates were reconstructed based on the biostratigraphic-age constraints of marine dinoflagellate cysts (dinocysts). Trace elements-based ratios and relationships were used in order to study the role of clastic terrestrial input. Three groups of dinocysts and freshwater Pediastrum algae were used to study the water-column conditions. Results showed that the Abu Roash A Member was deposited under oxic to intermittently dysoxic conditions in a distal inner to middle neritic environment, with varying sedimentation rates from 32 to 119 mm kyr−1. Productivity appeared to be a significant factor for determining magnitudes of the organic carbon accumulation; however, low productivity was prevalent during deposition. Carbonate content was high, which resulted in dilution of organic matter during varied rates of sediment input. Such results indicate that the paleoceanographic conditions in the southern Tethys witnessed the absence of prevalent oceanic anoxia (i.e., the Coniacian-Santonian OAE 3) and deposition of the CORBs as in several parts of the Tethys, the Pacific, and the Indian oceans. • Upper Coniacian-lowermost Campanian succession is fully investigated. • At the southern Tethys, oxic to minor dysoxic environments were predominant. • Dinocysts showed prevalent enhanced water-mixing to minor density stratification. • A dilution to destruction scenario was suggested for the current OM-poor sediments. • This region witnessed deposition of oxic CORB and the absence of oceanic anoxia (OAE 3). [ABSTRACT FROM AUTHOR]