الفهرس 
CHAPTER (I) INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The northern Western Desert is the second most important oil-producing area in
Egypt. Meanwhile the available geological database specially in the East Yidma oil
field was found of very poor quality and insufficient for routine approach, mainly
biostratigraphy, paleoecology, and source rock evaluation. The first detail
palynological and biostratigraphical studies in addition to the organic geochemical
analyses have been presented in the present work. A total of 59 subsurface cuttings
samples collected previously by the General Petroleum Company (GPC) from The
Drazia-1 well in East Yidma oil field have been selected for this study. The studied
intervals comprise three formations: 1) Khoman Formation composed mainly of
chalky limestone cherty in the upper most part, 2) Apollonia Formation composed of
limestone intercalated with shale and 3) Dabaa Formation composed mainly of shale.
The palynologicl investigation in the Drazia-1well, East Yidma concession, north
Western Desert, Egypt, have yielded the following conclusions:
1. The palynofacies analysis in the Drazia-1 Well reflects a high abundance of AOM
in the Upper Cretaceous succession of Khoman Formation, and high abundance of
brown and black phytoclasts in the Eocene-Oligocene succession in Apollonia and
Dabaa formations.
2. The statistical analysis based on the ratio of sedimentary organic material groups
(palynomorphs, phytoclasts and AOM groups) yielded two playnofacies assemblages
(cluster A and cluster B). Cluster A comprises all samples from the depth interval of
4000 to 4990 ft. and is characterized by a relatively high percentage of phytoclasts
while cluster B involves the lower interval samples from the depth of 5000 to 5990 ft
and is characterized by a relatively high percentage of AOM.
3. The microscopic examination of the studied samples led to the recognition of 154
palynomorph species (115 dinoflagellates, 37 spores, pollen grains and 2 acritarchs
species).
4. Five dinoflagellate cyst biostratigraphic zones from Santonian to Oligocene age
have been recognized from old to young as following:
4.1. Odontochitina operculata Interval Zone belonging to the age of Santonian to
Campanian, from the interval depth of 5990ft. to 5470ft. This zone is extended from
the first occurrence of Odontochitina operculata to the first occurrence of Cerodinium
diebelii.
CONCLUSIONS
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4.2. Cerodinium diebelii Interval Zone belonging to Maastrichtian age, ranges from
the first occurrence of Cerodinium diebelii.at the depth of 5470ft to the FO of
Damassadinium californicum. at the depth of 5060ft.
4.3. Damassadinium californicum Interval Zone. (interval from the FO of
Damassadinium californicum to the FO of Wetzeliella symmetrica). The age
assessment of this zone is Early-Middle Paleocene (Danian-Selandian age), from
5060ft. to 4910ft depth.
4.4. Apectodinium homomorphum Interval Zone. (Late Paleocene-Middle Eocene
(Thanetian-Bartonian age). This zone is range from the FO of Apectodinium
homomorphum at 4910ft depth to the FO of Deflandrea antaractica at 4710ft depth.
4.5. Deflandrea antaractica Interval Zone., range from the FO of Deflandrea
antaractica to the LO of Deflandrea antaractica (4710ft. to 4470ft.interval depth).
The age assessment for this zone is Late Eocene-Oligocene (Priabonian- Chattian
age). The interval from the depth of 4470ft to 4000ft. have no marker dinocysts
,therefore it is assigned by question mark.
5. The established palynozones have been correlated with equivalent Late Cretaceous-
Paleogene dinocyt biozones, locally in Western Desert of Egypt and globally in
Eastern New Zealand, Southeastern Australia, Cote dIvoiee, Ghana and Nigeria.
6. The quantity of organic matter in the source rock of Drazia-1 well was evaluated by
measuring the amount of TOC, and S2. The organic geochemical and pyrolysis
analysis for the selected samples yielded high TOC values ranging from 1.1231 to
1.6956 wt% but the S2 is ranging from 0.66 to 1.36 mg/g, indicate poor source rocks
in Khoman, Apollonia and Dabaa formations.
7. The Rock-Eval pyrolysis from the relationships between HI and Tmax . well
indicates a kerogen type III. Furthermore, the production index of the Khoman,
Apollonia and Dabaa formations ranging from 0.08 to 0.13 indicates immature source
rocks.
8. The qualitative and quantitative analysis of the studied interval yielded two
palynofacies assemblages, combining with dinocyst group distribution indicate the
following two marine environments:
8.1. Shallow marine (Inner neritic environment) for the upper part of the Drazia-1
well (Apollonia and Dabaa formations, depth from 4020 to 4990ft) ranging in age
CONCLUSIONS
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from Paleocene to Oligocene, composed mainly of shale intercalated with limestone.
It is characterized by a relatively high gamma ray assessment. The calcium carbonate
content is ranging from 0.6 to 7.6 wt% in shale and 20 to 67 wt% in carbonate
sediments. Almost samples of this interval are located in palynofacies or cluster A
which contains enormous amounts of terrestrial translucent and phytoclasts in
addition to the sporomorphs. Palynofacies assemblage A is plotting in the AOMphytoclast-
palynomorph ternary diagram of Tyson (1995) in fields I and II, that
represent a highly proximal shelf or basin (fields I) and Marginal dysoxic-anoxic
basin (fields II).
8.2. Deep marine (Middle neritic environment) in the lower part of the studied well
(depth from 5000 to 5990 ft) is belonging to the Upper Cretaceous age of Kkoman
Formation, composed mainly of carbonate sediments with a calcium carbonate
content ranges from 30 to 60 wt% and is characterized by low gamma ray values. The
Palynomorph forms suggest that sediments of the Upper Cretaceous were deposited in
a relatively deep marine environment. Almost samples in this interval are belonging
to palynofacies assemblage B, contain high abundance of AOM (56.6-91.6%) with
low abundance of phytoclasts (less than 10%) and low abundance of palynomorphs.
Almost samples of this cluster are plotted in the field IX of Tyson (1995) which
indicates a shelf setting having suboxic–anoxic conditions.