Petroleum system analysis

1. Petroleum system analysis of the Khatatba
Formation in the Shoushan Basin, north
Western Desert, Egypt.
By
• Adham Haitham Hamada
Under the Supervision of
• Dr. Ali Halim

2. Location map of Mesozoic Shoushan Basin in the north Western Desert of
Egypt, including studied fields
●the Shoushan Basin, north Western
Desert, Egypt
● Shoushan Basin is the most
productive basin in the north
Western Desert of Egypt
● The Khatatba Formation is
widespread in the Shoushan Basin
and attains a thickness (283–358 m)
in the basin

3. structural history of the
area
● Compressional anticlines are
subordinate and probably derive from
drag folding, related to lateral
movement along basement faults
● The structures in the north Western
Desert, focusing on the Shoushan
Basin, consist mainly of parallel,
elongated, tilted fault blocks, that is,
horst and half-graben structures, with
associated erosion of the upthrown
blocks

4. Stratigraphic history of the area
●The stratigraphy can be divided into fourunconformity-bound
cycles
● The earliest Jurassic cycle consists of non-marine
siliciclastics (Ras QattaraFormation), which rest
unconformably on the Palaeozoic Nubian sandstone and
are overlain by the Middle Jurassic Khatatba Formation
● The Khatatba Formation is composed mainly of
sandstones with organic-rich shales and coal seams.
These sediments were deposited in a deltaic to shallow
marine environment
● The Khatatba Formation underlies the Upper Jurassic
shallow-marine carbonates of the Masajid Formation, which
is capped by the Cimmerian unconformity, recording a
period of uplift, tilting,partial erosion and karstification of the
Jurassic succession
● In regard to seal rocks, the carbonate Masajid Formation
is the most important regional seal for the Khatatba
reservoir rocks in the Shoushan Basin because of its
widespread distribution and large individual bed
thicknesses that are generally in the range of 56–103 m

5. Source rock characteristics
●The Middle Jurassic coaly shales and organic-rich
shales of the Khatatba Formation were identified as
source rocks in the Shoushan Basin
● In contrast, the shales and coaly shale intercalations
within the Khatatba Formation serve as good local
seals

6. ●Distribution of total organic carbon content (TOC weight
percent) versus depths (in metres) for Khatatba
● Kerogen typing carried out on whole-rock samples using
organic petrographic analysis revealed that the Khatatba
source
rocks consist predominantly of type III vitrinitic and a
mixture
of types II–III liptinitic and possess moderately to heavily
stained with bitumen

7. ● Kerogen typing carried out on whole-rock samples
using organic petrographic analysis revealed that the
Khatatba source
rocks consist predominantly of type III vitrinitic and a
mixture
of types II–III liptinitic and possess moderately to heavily
stained with bitumen
● by Photomicrographs
a) High bitumen staining associated with vitrinite
b) Inorganic compound of pyrite (Py)associated with clay
minerals
c) Liptinite (LIP) associated with vitrinite (VR) and clay
minerals
d) t ultraviolet light showing unstructured amorphous
organic matter fluorescing greenish-yellow
e) High concentration of fluorescing sporinite
f) Unstructured organic matter (bituminite) fluorescing
orange to yellow associated with clay minerals

8. ● Hydrogen index versuspyrolysis Tmax for the Khatatba
source rock, showing kerogenquality and thermal maturity
stages
● Khatatba source rocks show HI values in the range of 63–261
mg HC/g TOC
●Khatatba samples that contain type III kerogen would be
expected to generate gas
●the samples with hydrogen index >200 mg HC/g TOC would
generate gas and limited components of liquid hydrocarbon

9. Maturation
• Maturity does affect the hydrogen index of the samples and
hydrocarbon generation relatively decreases hydrogen index
• typical
type II kerogen of thermal maturity equivalent to 0.77 to
1.07 % Ro has reached ∼30 to 80 % fractional conversions
(transformation ratio)

10. Hydrocarbon generation
●the oil window (corresponding to 0.50–0.60 %Ro)
of the Khatatba source rocks
● The Khatatba source rock reached the main oil
window at the end of the Late Cretaceous, and the
gas window occurred in the Tertiary

11. Reservoir rocks
● Khatatba Formation is considered themain reservoir
rocks in the Shoushan Basin. Thin-section petrography
shows that the Khatatba sandstones are mostly quartz
arenite, which composed mainly of more than 95 %
quartz with non-quartz content
● the Khatatba sandstones have normal porosity
distribution with an average values ranging from 1 to 17
%, and measured permeability valuesrange from 0.05 to
1,000 mD
● The cements recognized in the Khatatba sandstones
are calcite, quartz overgrowth, authigenic kaolinite and
pyrite

12. Seals and overburden rocks
● In regard to seal rocks, the carbonate Masajid
Formation is the most important regional seal
for the Khatatba reservoir rocks because of its
widespread distribution and large individual bed
thicknesses that are generally in the range of
56–103 m
● Other minor important seal rocks are shales
of the Dahab and Abu Roash Formations and
other Tertiary rock units
● Overburden rocks range from Upper
Jurassic to Tertiary, which have an influence on
source rock maturation and organic matter
transformation of the Khatatba Formation. The
present burial depth of most traps occurs at
depths greater than 3,000 m and generally
between 3,500 and 3,900 m. In addition
● Basin has a higher than average geothermal
gradient based on bottom-hole temperatures
(>120 °C) his is creating corresponding level of
thermal maturity that is capable of generating
an economically adequate amount of
hydrocarbons.

13. Trap Formation
● The structural traps of the north Western Desert
including Shoushan Basin formed during
Palaeozoic time resulting primarily from vertical
movement of basement blocks and
consisted of block faulting and gentle folding with
marked
unconformities
● These traps developed during the early
Mesozoic Alpine orogenic phase
● he 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

14. Hydrocarbon migration and accumulation
● hydrocarbon migrates through micro-fractures created by abnormal pore pressures resulting from hydrocarbon
generation
● primary migration within the Khatatba Formation
has been interpreted to be by abnormal pore pressures causing hydrocarbon expulsion through micro-fracture
● 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

15. Events chart of the Khatatba-Khatatba (!) petroleum system in the Shoushan Basin showing the
essential elements and processes (generation,migration and accumulation)