The document discusses the khatatba petroleum system in Egypt's shoushan basin, detailing its geological formation, structural history, and the characteristics of the source and reservoir rocks. It highlights the significance of the middle Jurassic khatatba formation as a rich source of hydrocarbons, particularly gas and oil, and outlines the processes of hydrocarbon generation, migration, and trapping in the region. Key findings include the formation's stratigraphic history, structural traps, and the conditions for hydrocarbon accumulation, validated through extensive geological analysis.

1. Khatatba Petroleum System
By: Mahmoud H. Abdelrazek
25 November 2023

2. Petroleum System Analysis
• Petroleum System: Geologically defined
elements and processes that generate,
migrate, and trap hydrocarbons. Includes
source rocks, reservoir rocks, migration
pathways, and traps
• Common techniques in petroleum system
analysis: seismic surveys, well log analysis,
geochemical analysis, and basin modeling.
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3. Khatatba Formation
• Khatatba Formation is a geological formation
located in the Shoushan Basin, North Western
Desert, Egypt. It is a Middle Jurassic formation,
approximately 174 to 163 million years ago.
• It is an important target for oil and gas
exploration in the region because it contains
significant amounts of organic-rich shale and
coaly shale, which are important source rocks for
hydrocarbons.
• The formation has been the subject of extensive
study, including organic geochemical,
petrographic, and petrophysical analyses, which
have helped to identify the essential elements of
the petroleum system in this area.
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4. Structural history
• The north Western Desert of Egypt is characterized by a
Palaeozoic section overlying a crystalline basement. This
basement has undergone two phases of major deformation,
resulting in a north to northwest trending system of block
faulting and gentle folding with significant unconformities
within the Palaeozoic section.
• The north Western Desert comprises several coastal basins
that originated as rifts during the early Mesozoic in
association with the opening of the Tethys.
• The Shoushan Basin, the largest among these coastal basins,
is a half-graben system with a maximum thickness of Jurassic
to Palaeogene sediments.
• The structures in the north Western Desert, particularly in
the Shoushan Basin, primarily result from vertical movement
of basement blocks and consist of parallel, elongated, tilted
fault blocks known as horst and half-graben structures.
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Geological Setting

5. Geological Setting
Stratigraphic history
• the area can be divided into four unconformity-bound cycles. The earliest Jurassic
cycle consists of non-marine siliciclastics (Ras Qattara Formation) overlying the
Palaeozoic Nubian sandstone. The Middle Jurassic Khatatba Formation,
composed mainly of sandstones with organic-rich shales and coal seams, overlays
the Ras Qattara Formation. The Masajid Formation, consisting of Upper Jurassic
shallow-marine carbonates, caps the Khatatba Formation, and the Cimmerian
unconformity separates the two formations.
• The subsequent cycle begins with the Alam El Bueib Formation, which includes
sandstones and carbonates, followed by shale and a succession of sandstones.
The cycle culminates in the Alamein dolomite associated with the Aptian. The
cycle ends with Shale. The Kharita Formation, characterized by sandstones, is
overlain by the shallow-marine and nearshore deposits of the Bahariya
Formation. The depositional conditions deepen in the Upper Cenomanian Abu
Roash Formation, with widespread transgression during the Turonian. The
Khoman Chalk Formation, deposited only in the north Western Desert,
unconformably overlies the Abu Roash Formation. The Eocene Apollonia
Formation, Dabaa and Moghra formations (marine clastics), and Marmarica
Limestone complete the stratigraphic sequence.
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6. Source rock characteristics - Khatatba petroleum system
• Organic petrographic and geochemical characteristics are Based on the
statistical summary of 52 samples from the fields in the Shoushan Basin
• Pyrite and quartz are the main inorganic components observed in these
samples
• Samples have high TOC content (1.0–32.5 wt.%)
• Using petrographic analysis, consist predominantly of type III vitrinitic
and a mixture of types II–III liptinitic and possess moderately to heavily
stained with bitumen
• Khatatba samples that contain type III kerogen would be
expected to generate gas while the samples with hydrogen
index >200 mg HC/g TOC would generate gas and limited
components of liquid hydrocarbon
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7. Hydrocarbon generation - Khatatba petroleum system
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• Shams Field selected as a representative site to
model the timing of hydrocarbon generation.
• The models indicate that the onset of the oil
window (corresponding to 0.50–0.60 %Ro) of the
Khatatba source rocks occurred during the Late
Cretaceous (95–75 Ma; Fig. 11).
• The Khatatba source rock reached the main oil
window at the end of the Late Cretaceous, and
the gas window occurred in the Tertiary.
• In summary, hydrocarbon generation started in
the Late Cretaceous (90 Ma), and peak
hydrocarbon generation occurred during the
Tertiary (30–15 Ma).
• Conclusion, the Middle Jurassic Khatatba
Formation is a good source rock in the Shoushan
Basin and has the greatest ability to generate and
economically adequate amounts of hydrocarbon
(mainly gas and oil)

8. Reservoir rocks - Khatatba petroleum system
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• The hydrocarbons discovered in the Shoushan Basin occur hosted in
clastic and carbonate reservoir rocks within the formations and
members ranging from Lower Jurassic to Upper Cretaceous age
• Thin section petrography shows that the Khatatba sandstones are
mostly quartz arenite. These sandstones characterized by fine- to
coarse-grained, moderately to well sorted and mostly subangular to
subrounded with rare rounded grains
• Based on the petrophysical analysis, the Khatatba sandstones have
normal porosity distribution with an average values ranging from 1 to 17
%, and measured permeability values range from 0.05 to 1,000 mD
• Secondary porosity is also recognized in the Khatatba sandstones and
resulted from fracturing and dissolution of calcite cement and unstable
grains
• Thin section photomicrographs of Khatatba sandstones depicting: a
good reservoir quality characterized by coarse grains with good sorting,
no matrix or cements; dissolution of calcite cement; open fractures
giving high possibility for good quality reservoir and ; fracture saturated
with bitumen (black colour) indicating hydrocarbon generation and
migration

9. Seals and overburden rocks - Khatatba petroleum system
• The carbonate Masajid Formation is the most important
regional seal for the Khatatba reservoir rocks
• The range of bed thickness 56-103 m
• In contrast, the shales and coaly shale intercalations
within the Khatatba Formation serve as good local seals
• Other minor important seal rocks are shales of the Dahab
and Abu Roash Formations and other Tertiary rock units
• The present burial depth of most traps occurs at depths
generally between 3,500 and 3,900 m.
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10. Trap Formation - Khatatba petroleum system
• The structural traps of the north Western Desert
formed during Palaeozoic time resulting primarily
from vertical movement of basement blocks and
consisted of block faulting and gentle folding with
marked unconformities
• Schematic northwest–southeast geo-seismic cross
section showing two representative trapping styles
and general structural style across Shoushan Basin
• This tectonic event caused formation of the coastal
basins including the Shoushan Basin in the north
Western Desert. The Mesozoic structural traps were
reactivated and a climax developed during the
Tertiary from the end of the Oligocene to the Middle
Miocene time
• The Tertiary tectonic event caused deformation of
traps formed prior to the Oligocene and led to the
formation of newly formed traps of structural,
stratigraphic and combination types
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11. Hydrocarbon migration and accumulation - Khatatba petroleum system
• The best evidence of abnormal pore pressure due to
hydrocarbon generation is the presence of multiple fractures
that are observed in some sandstone samples within the
Khatatba Formation
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References
• Mohamed Ragab Shalaby et al (Sep.2013) Petroleum system analysis of the Khatatba Formation in the Shoushan Basin,
north Western Desert, Egypt. Arabian Journal of Geosciences
• Abdou AA, Shahata MG, Kassab MAM (2009) Petrography and probable reservoir potentiality of subsurface Jurassic rocks at
Abu Gharadig Basin and Shoushan Sub-basin, North Western Desert, Egypt. Aust J Basic Appl Sci 3:1206–1222
• Primary migration of HC in the study area is considered to be due to several mechanisms
• Hydrocarbon migrates through micro-fractures created by abnormal pore pressures resulting from hydrocarbon
generation.
• Secondary hydrocarbon migration in the Shoushan Basin is envisioned to be largely vertical, having occurred
along normal faults upwards from the Khatatba active source rock towards the traps

12. Thank you
By: Mahmoud H. Abdelrazek
25 November 2023