الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
One of Egypt’s major hydrocarbon provinces is the Nile Delta. It
contributes significantly to national production in Egypt and represents the
country’s bright future in the hydrocarbon sector, as evidenced by recent
enormous gas discoveries like the Zohr gas field, which reaches Egypt’s
domestic gas needs and makes it one of the largest gas exporters in the Middle
East.
The reservoirs in the Nile Delta were made up of stratigraphic and
structural traps, and they contain a lot of clay minerals, which have an impact
on how accurately petrophysical evaluations and reservoir calculations are
made. As a result, the hydrocarbon reserve estimation is inaccurate,
necessitating the implementation of reservoir characterization in sandy shale
reservoirs with a large vary of facies changes.
The aim of this study is monitoring the oil and gas trends though the
eastern part of the onshore Nile Delta, Egypt by using modern techniques of
2D seismic data reflection, Finding the reservoir zones in the Abu Madi
Formation and define them in West El Manzala field, and characterize the gas
reservoir levels within Abu Madi Formation in West El Manzala field, from
the seismic interpretation, petrophysical points of view, seismic attributes, and
seismic inversion.
West El Manzala Field occupies 82. km² of the eastern part of Onshore
Nile Delta. It lies at the western edge of El Manzala Lake, and east of the
Damietta Nile branch.it located between: Latitudes 310 15’ N, 310 25’ N. and
Longitudes 310 38’ E, 310 45’ E.
Summary and Conclusion
Abu Madi Formation consists of three tops Top Upper Abu Madi, Top
Lower Abu Madi Ⅰ, and Top Lower Abu Madi Ⅱ; this sequence from the top
to the bottom as seismic interpretation in chapter three.
According to petrophysical analysis Abu Madi Formation divided into
three rock units; Upper Abu Madi, Middle Abu Madi, and Lower Abu Madi;
and every rock unit subdivided into several zones according to presence of
shale and sand.
Upper Abu Madi equivalent to Top Abu Madi (TAM), Middle Abu Madi
equivalent to Top Lower Abu Madi Ⅰ (TLAM Ⅰ), and Lower Abu Madi
equivalent to Top Lower Abu Madi Ⅱ (TLAM Ⅱ) in seismic interpretation
chapter three.
Abu Madi Formation contains two reservoirs from top to the base of these
levels is Upper Abu Madi (TAM) and Middle Abu Madi (TLAM Ⅰ). Upper
Abu Madi is generally characterized by lower percentage of average shale
content (26.2%) with average effective porosity reaches 16.1 % at F-1 well
increasing towards the south to reach (28.8%) of average shale content and
16.8 % of average effective porosity at SF-2 well in that order. Hydrocarbon
saturation of Upper Abu Madi reaches to 76.4% at F-1 well in the north.
Upper Abu Madi Formation characterized by 25.5% of hydrocarbon
saturation in Upper sand reservoir at SF-6 well and 25.2% of hydrocarbon
saturation at SF-3 well in the center of study area.
Middle Abu Madi characterized by 20.9% average volume of shale,
15.5% of average effective porosity, and 63.6% of hydrocarbon saturation at
F-1 well.
Summary and Conclusion
Middle Abu Madi characterized by 28.6% of hydrocarbon saturation at
SF-6 well and 26.6% at SF-3 well.
A significant concentration of silty deltaic deposits and inter-fingering
transgression marine shale give it its distinctive changeable reservoir quality.
Seismic bright spots, which are typically located in the shallower part of the
seismic section, are excellent indicators of gas or light hydrocarbon
accumulations. It can help the interpreter in getting more information from
conventional seismic data, which can support the interpretation of
geomorphology and paleo-environments. Major channels are the most
common sorts of fluvial system components, and they are clearly displayed
with envelope and RMS amplitude attribute.
Through the application of some seismic attributes such as Signal
Envelope (Reflection Strength), we found that, this attribute method reflects
strong response of amplitude for the anomaly of the Late Miocene sandstone
of Top Abu Madi Formation and faint response for Bottom Abu Madi
Formation and middle Kafr El-Sheikh Formation as shown in Fig. (4.4).
Application of instantaneous phase attributes fig. (4.7) we found that, the
continuity and discontinuity in the study section showing good continuity of
layers of Abu Madi Formation.
After applying dominant frequency and instantaneous frequency
attributes as shown in figs. 4.8, and 4.9 it reveals high frequency (violet to
blue color) dominate the whole section except the Top Abu Madi and Bottom
Abu Madi Formation with lower frequency (yellow and yellowish green
color) reveals change in lithology or in fluids content. All these two anomalies
Summary and Conclusion
reflect lower frequencies zones (light green and yellow to red color) as it
shown in the instantaneous frequency attributes section.
After applying Relative Acoustic Impedance (RAI) attributes fig. (4.3) we
found different in impedance for many spots in the line reflecting major
change in lithology through the study area.
The results of the application of mean root square (RMS) and reflection
intensity attributes are shown in Figures (4.5) and (4.6) These attributes
methods reflect strong response of amplitude for the anomaly of the Late
Miocene sandstone of Abu Madi Formation and low response for middle Kafr
El-Sheikh Formation.
In chapter five, the studied wells of Abu Madi Field are classified into
three groups (Upper Abu Madi, Middle Abu Madi, and Lower Abu Madi)
according to the vertical distribution changes of both lithology and reservoir
potentialities; every rock unit subdivided into several zones according to
presence of shale and sandstone layers.
The results obtained from the litho-saturation cross plot in F-1 well
indicates that Abu Madi Formation is composed of two rock units; the Upper
Abu Madi unit is composed of sandstones with shale interbeds, the shale beds
increased downward. In which the Middle Abu Madi unit is composed of
shale with sandstone intercalation. UAM Sand and MAM Sand 1 are
considered as the main reservoirs in this well with gross thickness 45.90 m
and 13.60 m, and average shale volume is 17.4% and 16.8 % respectively. The
litho-saturation cross plot in SF-6 well indicates that Abu Madi Formation is
composed of two rock units; the Upper Abu Madi unit is composed of
Summary and Conclusion
sandstones with shale interbeds, the shale beds increased downward. In which
the Middle Abu Madi unit is composed of shale with sandstone intercalation.
UAM Sand and MAM Sand 2 are considered as the main reservoirs in this
well with gross thickness 26.8 m and 5.1 m, and average shale volume is
32.3% and 11.4 % respectively. The results obtained from the litho-saturation
cross plot in SF-3 well indicates that Abu Madi Formation is composed of two
rock units; the Upper Abu Madi unit and the Middle Abu Madi unit are
composed of shale with sandstone intercalation. UAM Sandy Shale 1 and
MAM Sandy Shale 1 are considered as the main reservoirs in this well with
gross thickness 55.3 m and 64.4 m, and average shale volume is 33.8 % and
34 % respectively. The results obtained from the litho-saturation plot analysis
in SF-2 well indicates that Abu Madi Formation is composed of three rock
units; the Upper Abu Madi unit is composed of sandstones with shale
interbeds, the shale beds increased downward. In which the Middle Abu Madi
and Lower Abu Madi units are composed of shale with sandstone
intercalation. UAM Sand and MAM Sand 2 are considered as non- reservoir
in this well with gross thickness 33.2 m and 13.6 m, and average shale volume
is 32.9% and 19.4 % respectively.
The lateral distribution of petrophysical characteristics (volume of shale
content, effective porosity, and water saturation maps) of each zone is shown
on the isoparametric maps of the Abu Madi Formation. The lateral variation
changes of shale volume in UAM Sandy Shale 1 zone in the studied area
shows that the high shale percentage gradient at the center part of the studied
area followed by the south east part and highly decreased toward the north
west direction. The shale content map of UAM Sand zone demonstrates that
Summary and Conclusion
the shale content increases at SF-2 well at the southern part area followed by
the center part, it decreases towards the northern part of the area. The lateral
variation of shale content in UAM Sandy Shale 2 zone in the studied area
increases toward the central and northern area, it decreases towards the
southern part. The lateral variation changes of shale volume in MAM Sandy
Shale 1 zone in the studied area shows that the high shale percentage gradient
at the center part of the studied area followed by the south east part and highly
decreased toward the north west direction. The shale content map of MAM
Sand 2 zone indicates that the shale content increases at the northern part area
followed by the southern part and it decreases towards the center part of the
area.
The effective porosity distribution map for UAM Sandy Shale1 zone
shows a decreasing of effective porosity towards the center and highly
increased toward the south direction. The effective porosity map of UAM
Sand zone indicates that the effective porosity reaches its maximum value in
the north of the area followed by the center and the minimum value towards
the southern part. The effective porosity distribution map for UAM Sandy
Shale 2 reveals that the lateral variation in porosity values increases towards
the southern part of the area and decreases towards the north part followed by
the center of the area. The effective porosity values of MAM Sandy Shale 1
zone increase at the center and the north directions of the studied area. The
minimum value at SF-6 well in the center and at SF-2 well in the south. The
effective porosity map of MAM Sand 2 zone indicates that the effective
porosity reaches increase generally toward the south and reached to its
Summary and Conclusion
maximum value in the center of the area followed by the south part and the
minimum value towards the northern part.
The average water saturation contour map of UAM Sandy Shale 1 zone
of Abu Madi Formation shows that the water saturation values increase at the
east central area at SF-6, and SF-3 wells and decreases towards the southern
part. The average water saturation map of UAM Sand zone increases in the
southern part of the area followed by the center part, it decreases towards the
north. The average Water saturation distribution map of UAM Sandy Shale 2
zone increases towards the center and decreases in all sides of the map.
Average Water saturation distribution map of MAM Sandy Shale 1 zone of
Abu Madi Formation in the study area increases in the central part of the study
area, it decreases towards the north. Average Water saturation distribution
map of MAM Sand 2 zone of Abu Madi Formation in the study area increases
towards the north, it decreases towards the south direction of studied area.
In chapter 6, post-stack inversion algorithms were used to create the
acoustic model by using the model-based inversion, the Bandlimited
inversion, color inversion, and sparse spike inversion especially linear-sparse
spike inversion these methods explain and revealing general increasing in AI
value with depth, where Abu Madi Formation shows increasing in acoustic
impedance (AI) values from that one in the lower part of Pliocene Kafr ElSheikh Formation. The comparative between the methods we can say that
color inversion method is the most robust, rapid, easy to use, robust and does
not require expert users one as it generates more detailed results and that is
clear and present when we look at the results for the two methods in the
seismic section where the F-1well is located.
Summary and Conclusion
Synthetic traces produced by the resulting AI were correlated with seismic
traces for wells.
For F1well, where there is good correlation between the logs and the
inverted result (Figs. 6.11 to 6.14), the synthetic traces produced from the
inversion result and the original seismic data correlated well. That show the
post-inversion validation plot for the Arbitrary line seismic section that passes
through the F1 well using model-based acoustic impedance inversion and
acoustic impedance band limited inversion, colored inversion, and linearsparse spike inversion with correlation percentages of 99.7% and 97.9%,
91.4%, and 99%. Errors of them are 1.6%, 1.5%, 1.05%, and 1.9% in that
order as shown in figures (6.8 to 6.11).
Finally, the results from application the seismic inversion method reveals
that, top of Abu Madi Formation is characterized by low acoustic impedance
compared with lower part of Kafr El-Sheikh Formation which could be due to
the effect hydrocarbon accumulation mostly gas at the north of the study area
around F-1 well with percentage of hydrocarbon saturation reaches to 76.4%
and average effective porosity attains 16.1% as shown from well log analysis
results, while the contrast between the higher acoustic impedance of lower
Kafr El-Sheikh and the lower acoustic impedance of Abu Madi Formation are
not that strong in the south east at SF-2 well where the percentages of water
increasing with the south.
Also, a high amplitude in Top of Abu Madi Formation is shown in Signal
Envelope, RMS Attributes section revealing strong response of amplitude for
Summary and Conclusion
the anomaly of late Miocene sand stone of Abu Madi Formation and low
response for lower Kafr El-Sheik formation.
On the other hand, AI of top lower Abu Madi level Ⅰ increases in acoustic
impedance than top Abu Madi Formation due to higher water saturation and
low hydrocarbon saturation in this layer than top Abu Madi Formation which
reaches to 64.4% and 15.5% average effective porosity.
In the south east at SF-2 well water increases and hydrocarbon decreases
so the acoustic impedance increases in the south than the north.
from all the above where the results revealing the effect of hydrocarbon
on both AI and amplitude of Abu Madi Formation, our Recommendation is
to do more studies in direction of north due to good reservoir quality from the
petrophysical analysis and what is revealed from using different enhancement
seismic methods like inversion and attributes