الفهرس 
CHAPTER ONE :GEOLOGICAL SETTINGOnly 14 pages are availabe for public view
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Abstract
The aim of this work is to evaluate the petrophysical parameters of Lower Bahariya Formation utilizing well logging data and core report.
Aghar oil field is located in West Razzak lease, North Western
Desert of Egypt, 66 km southwest of El-Hamra terminal on the
Mediterranean coast. The area is located between latitudes 30° 29’ and
30° 29’ 1’’ N and longitudes 28° 20’ 16’’ and 28° 20’ 37’’ E.
The logging data of seven wells (AG-1 ,AG-2X, AG-3X, AG-4,
AG-6 AG-7and AG-8) and core analysis results of Bahariya Formation in
( AG-2X) well are used for evaluating the petrophysical parameters and
hydrocarbon potentialities of Bahariya Formation. The used data are
obtained and licensed from Agiba Petroleum Company.
The present work deals with the computerized well logging analysis
by using Interactive PetrophysicsTM
(IP), where The studied rock unit
( Bahariya Formation ) is penetrated by seven drill holes distributed in
the area of study (AG-1 , AG-2 , AG-3 , AG4 ,AG-6, AG-7, AG-8 ) .
The available well logging data used in this work include the
gamma-ray logs, porosity tools (sonic, density and neutron logs) and
resistivity logs (deep and shallow) In the form of (LAS Format). The well
logging technique followed is started by entering the data raw and
determine the formation temperature. Then correcting the fluid and rock
resistivities, and also for the other environmental corrections.
Volume of shale contents are calculated using the Neutron, Gammaray
and Resistivity, in which the produced results are corrected through
clavier et al., equation (1971) and steiber equation (1973).
The way shaliness affects a log reading depends on the manner of
shale distribution in the formation .These types are dispersed ,laminated
and structural shales .Generally, the dispersed shale reduces the
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permeability of the formation, while the laminated shale decreases overall
average effective porosity and the structural shale has nearly the same
properties as the laminated shale
In the area under investigation, the shale has minimum value at
central area of the map where maximum value is represented in east and
west directions
Also, the formation porosities (total and effective) are determined
through the porosity tools (density, sonic and neutron). These porosities
are corrected for the effect of shaliness.
The total porosity distribution map shows a gradual increase toward the
southeast and southwest directions. While it decreases to the northeast
The effective porosity distribution map reflects a gradual increase to the
southeast and southwest directions, where decreases towards the north.
The water saturation of the study area is determined where Archies’s
formula (1942) is used to determine the water saturation in the clean
formation but in the presence of the different types of shales water
saturation is determined by INDONESIA equation.
The iso-parametrics map of water saturation shows that the value of
water saturation decrease in the central area while it exhibits the gradual
increase in all direction
Also hydrocarbon saturation is determined where hydrocarbon
saturation map exhibit increase in middle and decreases in all direction
where maximum value in (AG-1X) which is the reverse direction of
water saturation distribution map.
Also a lithology identification with cross plots (Neutron-Density),(Sonic-
Density)and (Sonic-Neutron) show that the main lithology is sandstone
,limestone, dolomite and shale .
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In the present study ,the produced petrophysical results were
represented, zone-wise, in the form of litho-saturation crossplots for four
wells to show the vertical variations of these parameters with depth.
Bahariya Formation is the main producing horizon in Aghar oil field.
It is represented by fine to very fine-grained sandstone, well sorted, subangular
to sub-rounded, straight to concave-convex contact alternated
with shales and limstones. It is divided into two zones, Upper and Lower,
each zone is subdivided into two sub-zones. Bahariya Formation was
deposited on a wide extensive shallow marine shelf .from litho saturation
cross plots we noticed that the oil appear in upper Bahariya and show
gradual increasing in Lower Bahariya especially in AG-3X at depth
(5820-5950 ft) and AG-8X at depth (5900-6900 ft) from this study it is
interpreted why the Lower Bahariya is the main pay zone at Bahariya
Formation, Aghar Field, Western Desert Egypt.
Laboratory work to core samples are executed in the American
University in Cairo where the selected samples are subjected to,
Conventional core analysis this analysis include the determination of
porosity, permeability, rock density and fluid saturation
The porosity of Bahariya Formation in AG-2x well varies from
4.8% to 32.4% for Boyle’s law porosity and varies from 5.1% to 35.2%
for residual fluid porosity. Porosity can be used to determine storage
capacity and to assess the quality of the reservoir. The obtained high
values of porosity indicate that the Bahariya Formation is represented by
high quality reservoir .
The horizontal permeability for the studied samples of Bahariya
Formation in AG-2X well ranges from 0.06 md to 5070 md and the
vertical permeability of the same samples varies from 0.07 md to 4830
md from the statistical analysis of the horizontal permeability and
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vertical permeability in Ag-2x well, it is concluded that the Bahariya
Formation is a good to excellent reservoir .
Water saturation data frequency and cumulative frequency for the
studied samples of L.Bahariya Formation indicated that the saturation
varies from 16.1 % to 96.3 % with a mean value of 67.4 %.
where About 3 interval core zones at different depths (5902-5930)
(5963-5990) (5994-6082) from the studied L..Bahariya Formation within
( Aghar-2X) were selected and correlated with logging data .
where the porosity values obtained from core analyses are nearly
coincident with those obtained from log analyses., and finally the process
appear that core analysis are mostly higher than log porosity ones at the
same depth This may be due to that the routine core porosity is normally
measured at atmospheric conditions and have been cleaned from oils and
dusts prior to measurements, while the log porosity was affected by in
situ net overburden pressure .
And with correlating the saturation values obtained from core
analyses with that obtained from logs it was found that, their values are
mostly coincident with each other .but The hydrocarbon saturation values
obtained from core analyses appear some variation may be due to the
bore hole conditions that may affect the resistivity readings which in turn
affect the saturation values obtained from the log analyses. Also with
presence of clay minerals affect the effective porosity of the reservoir as
it decrease the value of the effective porosity, while it increase the total
Porosity. The differential values of clay content in the studied reservoir
affect the reading of measured resistively (Rt), and this reflect the
difference in saturation from zone to another.