Qatar Univ. Sci. Bull. (1988), 8: 247-267 
PETROPHYSICAL STUDIES FOR SOME LOWER CRETACEOUS 
FORMATIONS, WESTERN DESERT, EGYPT 
By 
M.D. EL-DAIRY', A.A. EL-SAYED2 and M.A. EL-HEFNAWY2 
1. Deptartment of Geology, Al-Zagazig University, Egypt. 
2. Deptartment of Geology, University of Qatar. 
Key words: Lower Cretaceous, Electrical resistivity, Velocity. 
ABSTRACT 
The Kharita, the Dahab and the Alamein Formations are representing the upper 
part of the Lower Cretaceous rock sequence in the northern part of the Egyptain 
Western Desert. Some core samples have been obtained from these rock units. 
They are subjected for both electrical resistivity and rock porosity measurements . 
. . Formation factor-porosity relations at four different brine concentrations have 
been performed. Petrophysical exponents (a, m & n) of the Archie's general 
formulae have been determined at the in situ formation water resistivity (Rw "" 0. 72 
Ohm.m.). They are very helpful to perform an effective well-log interpretation for 
the studied intervals. 
In addition, the correlated relationship between the _variations in the interval 
velocities as a petrophysical character and the existing lithofiJ.cies changes in these 
above mentioned formations have been investigated. 
INTRODUCTION 
The study area (Fig. 1) comprises about 45000 sq.km being marked \jy Lat. 29°50 1 
and 31°401N and Long 25°001 and 28°001 E, in which hydrocarbon exploration 
activities were carried out by different operators since 1940. 
The drilled rock succession, in the study area, includes a sedimentary sequence 
ranging in age from Cambro-Ordovician to the Recent (Metwalli et al, 1979). The 
Lower Cretaceous rock sequence has been considered as a source of attraction for 
many petroleum geologists. This might be due to its probable high hydrocarbon 
Petrophysical studies for some lower Cretaceous formations 
potentiality. In the study area, the Lower Cretaceous rocks have been cored in few 
wells. Therefore, the all geological studies formerly done are mainly based on ditch 
samples (drill-cuttings). 
Regional geology, structure, settimentology and stratigraphy of the Lower 
Cretaceous rock units have been comperhensively studied by different authors 
(El-Gezzery et al, 1972; Abdin and Deibis, 1972; Barakat and Arafa, 1972; 
Metwalli and Abdel-Hady, 1973 & 1975; Philip et al, 1980; and Barakat and 
Darwish, 1984). The Lower Cretaceous sequence has been classified into different 
rock units by different authors (Tab. 1). In the present study, the classification 
assumed by Barakat and Darwish (1984) has been adopted. 
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M.D. EL-DAIRY, A.A. EL-SA YED, and M.A. EL-HEFNA WY 
In addition, the well velocity survey data from 24 wells located in the concerned 
area and 23 core samples were obtained from the Egyptain General Petroleum 
Corporation and used in the present study. Out of the 23 core samples, only 9 
calcareous sandstone samples were from the Kharita Formation, while 2 calcareous 
sandstone samples were from the Dahab Formation. Only 5 samples were 
belonging to the Alamein Formation. The rest are broken during measurements. 
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Petrophysical studies for some lower Cretaceous formations 
The objective of the present study is to determine the different petrophysical 
parameters needed for reservoir description and fluid saturation detection. In 
addition, the litho-velocity relationships are investigated in order to enhance 
reservoir zonation. 
METHODS AND TECHNIQUES 
The available full-diameter well-core samples are drilled into small plugs of 2.5 em 
diameter and 4.0 em length. These plugs are cleaned from the residual 
hydrocarbons by use of different types of organic solvents and s~helt extractor 
apparatus (Keelan, 1972). 
In order to study the conductive solids (clay minerals) in the reservoir rock pore 
spaces, four different brine solutions were prepared. They used for sample 
saturation to measure sample electrical resistivity in four measuring series. 
They were selected in manner that two of them are less concentrated than the in 
situ formation water concentration (1/100 and 1/200 times). The concentration of 
the saturant used in the third measuring cycle was 140 grnlf (in situ concentration). 
The last one has a concentration of 1.3 times of the in situ formation water 
concentration. 
Electrical resistivity measurements starts after the accurate estimation of the plug 
dimensio:I.l~ \V~letl!e samples w~re 100% saturated with the most dilute solution: 
The electrical resistivity (R0 ) was measured at normal conditions (Tab. 2) by use of 
a universal bridge type (Model T.F. 2700), feed-back function generator (FG-601), 
and a Hassler type core holder with two copper electrodes covered with chamois 
pads. In order to minimize- the electrode polarization, a minimum constant A. C. 
current (3;.5 rnA) of lOOb Hz frequency (Hassan, 1969) was used during the all 
measurements. On the other hand, sample porosity was measured (Tab. 2) on the 
same plugs by use of the saturation method adopted by Koithara et al., (1965). 
The resistivity index (I) is determined by measuring the electrical resistivity of 
desaturated sample (Rt) at different values of water saturation (Sw)· The samples 
were saturated with a brine concentration equivalent to the in situ formation water 
concentration (Table 3). 
The delineation of the relationship between the variation of the interval velocity in 
the Alamein, the Dahab, and the Kharita Formations and their lithofacies changes 
have been done. The interval velocities for these formations have been computed 
from the available well velocity survey data of 24 wells scattered allover the 
concerned area (Fig. 2). Tab. 4 shows the computed interval velocities for these 
formations in some selected wells. 
250 
Table 2 
The measured resistivity value, the corresponding formation factors and porosity fraction: 
Alamein Carbonates (Ghazalat Well) 
Sample Well Name Rwl = 5.4 Ohm.m Rw2 = 4.5 Ohm.m Rw3 = 0.72 Ohm.m 
No Ro F Ro F Ro F Ro F Ro F Ro 
17 Ghazalat 23.7 43.9 216.0 40.0 229.6 51.03 170.8 38.0 106.9 148.5 91.8 
18 Ghazalat 140.4 26.0 118.8 22.0 129.6 28.8 113.4 25.2 32.7 45.4 41.3 
19 Ghazalat 351.0 65.00 242.1 63.4 299.0 66.4 329.4 73.2 134.0 186.0 144.6 
20 Ghazalat 133.6 34.7 154.4 28.6 124.2 32.03 124.7 32.2 59.9 83.15 63.3 
21 Ghazalat 297.0 55.0 275.2 50.9 196.3 43.6 214.6 47.7 101.8 141.4 113.7 
Upper Alamein Clastics. 
22 Mersa-Matruh 13.5 2.5 14.02 2.6 13.2 2.94 13.5 3.00 6.12 8.5 5.80 
23 Mersa-Matruh 15.3 2.8 14.3 2.64 11.2 2.9 13.9 3.10 6.82 9.5 5.99 
24 Mersa-Matruh 28.5 5.3 28.5 5.3 27.4 6.1 30.2 6.70 28.80 40.0 29.00 
25 Faghur 17.3 3.2 19.4 3.6 14.8 3.3 16.3 3.60 10.80 15.0 10.50 
26 Faghur 15.3 2.8 15.3 2.8 12.5 2.7 12.75 2.70 6.90 9.6 7.13 
29 Ghazalat 15.25 2.82 13.4 2.5 12.1 2.68 12.1 2.60 6.42 8.9 6.50 
31 Mersa-Matruh 30.2 5.6 31.9 5.9 26.5 5.88 27.9 6.20 32.40 45.0 33.60 
-----
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Petrophysical studies for some lower Cretaceous formations 
Table 2 (Contd.) 
Alamein Carbonates (Ghazalat Well) 
Sample Rw4 = 0.06 Ohm.m 
No Well Name Porosity 
Ro F Ro F Fraction 
17 Ghazalat 10.9 181 9.36 156.1 0.031 
18 Ghazalat 3.33 55.6 4.23 70.6 0.058 
19 Ghazalat 15.6 260.0 16.5 275.0 0.054 
20 Ghazalat 6.04 100.7 6.5 107.8 0.042 
21 Ghazalat 10.3 172.3 11.55 192.5 O.o35 
Upper Alamein Clastics. 
22 Mersa-Matruh 0.67 11.22 0.612 10.2 0.250 
23 Mersa-Matruh 0.72 12.10 0.690 11.5 0.219 
24 Mersa-Matruh 3.20 53.30 3.100 52.4 0.102 
25 Faghur 1.20 20.00 1.200 20.0 0.186 
26 Faghur 0.76 12.75 0.775 12.9 0.200 
29 Ghazalat 0.67 11.22 0.650 10.9 0.283 
31 Mersa-Matruh 3.60 59.80 3.600 60.7 0.100 
Table 3 
Calculation of Resistivity Index versus water saturation for the studied samples 
Sample 0.0 rpm 1000 rpm 2000 rpm 3000 rpm 
No Ro(Ohm.m) 
I1 sw 12 sw 13 sw 
Upper Alamein Clastics (Horizontal Direction) 
22 0.8160 1.2500 0.5284 0.5350 0.1439 2.2868 0.0682 
23 0.8160 1.0625 0.6160 1.8750 0.2740 2.5000 0.0479 
24 1.3908 1.2295 0.8270 1.3197 0.6380 1.6393 0.5172 
25 0.8480 *** *** *** *** *** *** 
26 0.8262 1.0247 0.5632 1.5309 0.4655 1.8518 0.3735 
29 1.0980 1.1111 0.6983 1.2222 0.2500 1.7778 0.1983 
31 1.4364 1.0978 0.8420 1.2030 0.7543 1.3158 0.6666 
Upper Alamein Clastics (Vertical Direction) 
22 0.7140 1.1143 0.5284 1.9571 0.1439 2.5428 0.0682 
23 0.9180 1.2778 0.6160 1.6444 0.2740 1.7277 0.0479 
24 1.4421 1.2253 0.8270 1.5810 0.6380 1.5810 0.5172 
25 0.9050 *** *** *** *** *** *** 
26 0.8466 1.0181 0.5632 1.8072 0.4655 1.3617 0.3735 
29 0.9150 1.2000 0.6983 1.1667 0.2500 1.9870 *** 
31 1.8360 1.0294 0.8420 1.0588 0.7543 1.1000 0.6666 
252 
M.D. EL-DAIRY, A.A. EL-SA YED, and M.A. EL-HEFNA WY 
Table 3 (Contd.) 
Alamein Carbonates (Horizontal Direction) 
17 6.3240 3.1452 0.3333 4.1942 0.0100 6.2903 0.0050 
18 5.1040 1.0933 0.7500 1.1853 0.6250 1.2962 0.3125 
19 9.5400 1.8218 0.3080 2.2787 0.1540 2.4444 0.0050 
20 6.5720 2.4516 0.3846 3.4510 0.1538 3.7097 0.0050 
21 6.4900 2.0339 0.1800 5.2800 0.0625 6.9491 0.0050 
Alamein Carbonates (Vertical Direction) 
17 6.0690 2.3064 0.3300 2.6554 0.0100 2.7395 0.0000 
18 5.1700 1.0174 0.7500 1.2659 0.6250 1.8549 0.3125 
19 9.4870 1.2290 0.3080 1.3408 0.1540 1.8994 0.0000 
20 6.6250 1.6080 0.3846 1.9120 0.1538 2.7200 0.0000 
21 5.7500 1.8435 0.1800 3.0609 0.0625 3.6348 0.0000 
t.-t.-t.-These samples were broken during experimental tests. 
FORMATION FACTOR-POROSITY RELATION 
The relationship between the formation resistivity factor and the porosity of a 
porous medium has been investigated both theoritically (Fricke, 1924; Clavier, et al 
and Bussian, 1983) and empirically (Archie, 1942; Perez-Rosales, 1982; Hassan 
and EI-Sayed, 1983; and El-Sayed, 1987) through more than 50 years. Laboratory 
studies indicate that pore space framework, in which the electri<; conduction take 
place, is not rather simple. The pore-wall, which consists of grain surfaces, in 
reservoir rocks is extremely irregular due to many diagenetic controls (authigenetic· 
mineral growth and/or desolution). This irregularity, in most cases, creates regions. 
of stagnation called traps. Therefore, the pore space can be divided into flowing; 
and stagnent region (Perez-Rosales, 1982) for fluids as well as for electric currents. 
From this view point, the formation factor-porosity relation depends upon the pore 
space history. 
The formation factor - porosity relations of both the Kharita and the Dahab 
Formations as clastic units (upper Alamein clastics) were constructed to reveal the 
probable effect of the brine concentration on both the cementation exponent(m) 
and the multiplier(a) of the Archie's general equation; 
F = a.0·m _ ---------- _ (1) 
Where; F = formation resistivity factor, 
0 = rock porosity, fraction. 
253 
N 
'Jl 
.j::. 
WELL 
FORMATION 
Kharita 
Dahab 
Alamein 
Mideiwar 
Abyad 
Matruh 
Alam EI-Bueib 
Betty 
Abyad 
v 
int 
1555 
1669 
2027 
1875 
2666 
1928 
1921 
1883 
Mideiwar Siqeifa 
v v 
int int 
3720 3567 
3857 3643 
3963 4070 
3750 3598 
4756 3506 
3659 3659 
3537 3667 
>3537 3918 
Table 4 
Formation velocity analysis. 
Kanayis Khalda Urn Barka Louly 
v v v v 
int int int int 
3796 4009 3963 4299 
4314 4070 4268 4131 
4869 4726 4558 4619 
3659 4223 4329 4467 
4131 5031 4695 5534 
- 4345 3963 4619 
- - 4512 4588 
-
--
3329 -
"--
Yakout Ghazalat-N EI-Basour 
v v v 
int int int 
3277 2810 2735 
Missed 2875 Missed 
Missed 2895 Missed 
Missed 2990 Missed 
Missed 2915 2760 
3689 3015 2746 
3963 3065 Missed 
4009 Missed Missed 
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M.D. EL-DAIRY, A.A. EL-SA YED, and M.A. EL-HEFNA WY 
500 
\ 
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One Way Vertical Time (usee) 
560 
\ 
\ 
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Average Velocity 
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FORMATION 
Kharita 
Dahab 
Alamem 
Mideiwar 
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Matruh 
Alam 
El Bueib 
etty 
Jurassic 
Fig. 2: Abyad Well Formation Velocities 
LITH 
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The plot (Figs 3&4) exhibits the formation factor versus rock porosity for the 
samples of the upper Alamein clastics (Figs. 3A&B) and samples from the Alamein 
Formation (Figs. 4A&B) at four different brine concentrations. The electrical 
resistivity of the fully saturated (100%) rock (Ro) was measured in both horizontal 
and vertical directions. 
The analysis of these relations indicates that the calculated cementation ex-
ponent(m) increases vigorously by the increasing of the brine concentration. 
Nevertheless, the multiplier(a) almost remains constant with value about 1.0. This 
phenomenon can be explained by the existence of clay minerals of high cation, 
exchange capacity (CEC) acting as conductive solids among the reservoir rock 
formation fines. Clay minerals were mainly kaolinite and illite (El-Dairy, 1986). 
255 
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Petrophysical studies for some lower Cretaceous formations 
A Horizontal 
100,----------------------------. B Vertical 
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1 
100 
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10 
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Porosity (0f) 
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Fig. 3: Formation Factor-Porosity Relation for the Upper Alamein Clastics 
256 
M.D. EL-DAIRY, A.A. EL-SAYED, and M.A. EL-HEFNAWY 
A Horizontal 
1~c-----------~ 
10~--~~~~~w 
1~ .-------------.., 
\ 
'\ 
10 '-----'--~~~......, 
0.01 0.1 0.01 
Rw=4.5 Om' 
0.1 0.01 
Porosity (0,) 
B Vertical 
Rw=5.4 Om Rw=4.5 Om 
Rw = 0.72 Om \ Rw=0.06 Om 
\
.<'>'\\ 
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• <P 
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., \ 
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\ 
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0.1 0.01 0.1 
Fig. 4: Formation Factor-Porosity Relation for the Alamein Carbonates (Ghaza-
lat Well). 
257 
Petrophysical studies for some lower Cretaceous formations 
(a/m) RATIO 
An attempt was made to calculate the value of (a/m) ratio for both the horizontal 
and the vertical directions of electric resistivity measurements (Tab. 5). The data 
reveals constant values for samples of both upper Alamein clastics and Alamein 
Formation when rock samples were saturated with dilute solutions (0. 7 & 1.4 gm/1). 
The values of (a/m) ratio are slightly decreased as the brine concentration increased 
especially in case of limestone samples of the Alamein Formation. 
On the other hand, the values of (a/m) ratio have been decreased vigorously by the 
increasement of the brine concentration (140 & 182 gm/1) in case of sandstone 
samples of the upper Alamein clastics (Kharita and Dahab Formations). The 
authors believe that the (aim) ratio could be used as a lithofacies and a hydrofacie5 
indicator. Its application could be extended to performing reservoir zonation. 
RESISTIVITY INDEX 
Resistivity index (I) is defined as the ratio of the electrical resistivity of a part.ially 
saturated sample(Rt) to its electrical resistivity as 100% saturated (R0 ) with brine 
solution; 
I C. Sw -n (2) 
Table 5 
The Multiplier (a) and the Cementation Factor (m) of the General Relation 
(F = a.0-m) 
Alamein Carbonates 
Brine Con. 
* * ** ** 
gm/1 Rw(Om) a" mH av mv · ah/inH avlmv 
0.7 5.4 0.998 1.12 0.970 1.10 0.9 0.9 
1.4 4.5 0.998 1.12 0.98 1.11 0.9 0.9 
140.0 0.72 0.960 1.42 0.98 1.41 0.7 0.7 
182.0 0.06 0.950 1.50 0.98 1.51 ? 0.6 ? 0.8 ? 
Upper Alamein Clastics 
0.7 5.4 0.995 0.73 0.96 0.75 1.3 1.3 
1.4 4.5 0.970 0.77 0.95 0.812 1.3 1.3 
140.0 0.72 0.981 1.62 0.96 1.50 0.6 0.6 
182.0 0.06 0.991 1.80 0.997 1.75 0.56 0.56 
* aH and mH are the multiplier and cementation factor in horizontai direction respectively. 
** av and mv are the multiplier and cementation factor in vertical direction respectively. 
258 
M.D. EL-DAIRY, A.A. EL-SAYED, and M.A. EL-HEFNAWY 
Where; c = multiplier 
Sw=water saturation, fraction. 
n = saturation exponent. 
Resistivity index is used as a guide to possible production of a certain fluid under 
reservoir conditions. The resistivity index(I)-water saturation(Sw) relations, repre-
senting both the upper Alamein clastics and samples of the Alamein Formatio~, are 
shown in Fig. 5. An examination of the data (Tab. 4) plotted (Figs. SA&B) reveals 
that; 
1. The multiplier (c) equals 0.93 for horizontal direction and equals 0.91 for the 
vertical one. 
2. The saturation exponent (n) is relatively very low (n=0.37 and 0.41) for 
horizontal and vertical directions respectively. These low values may indicate 
that the upper Alamein clastics are entirely water-wet (Wyllie, 1963). 
The analysis of the plot (Figs. SC&D) shows that the calculated multiplier(c) 
through out the two measuring directions is nearly of the same value ( c = 1. 7 &1.6). 
The calculated saturation exponents in the two directions are very low. It implies 
that rocks of the Alamein Formation are mainly water-wet. 
The regression line equations (Figs. SA&C) calculated in horizontal direction for 
both the upper Alamein clastics and the Alamein Formation could be used for fluid 
saturation estimation. 
LITHO-VELOCITY ANALYSIS 
Figures 6,7 and 8, demonstrate the constructed velocity gradient maps of the 
interested formations (Alamein, Dahab and Kharita). The correlation between 
these maps with the lithofacies distribution maps of these formations (El-Dairy, 
1986) illustrate that these velocity gradient maps can give a clue to these lithofacies 
variations. 
The velocity gradient map of the Alamein Formation is represented in Fig. 6. It 
illustrates a variable increasing rate of velocity from high values as in the northern 
portions (Mamura and Marsa-Matruh areas) to low values as in southeast and 
southwest portions of the area. This is due to the slightly facies change, in general, 
from the highly velocity dolomite to less velocity dolomitic limestone (El-Dairy, 
1986). These dolomite and dolomitic limestone are streaked with minor and thin 
beds of shales (central portion) or sandstone (southern and southwestern portions) 
which decrease the velocity considerably in these portions. 
The velocity gradient map of the Dahab Formation (Fig. 7) shows, in general, 
features similar to that existed in Alamein Formation, while the lithofacies maps of 
259 
Petrophysical studies for some lower Cretaceous formations 
the two formations (EI-Dairy, 1986) are slightly different. This may be due to the 
composition of the Dahab Formation which is formed of hard calcareous dolomitic 
shales with frequent carbonate streaks. Towards the southeastern and southwest-
ern portions of the concerned area, which is thought to be an uplifted areas 
(El-Dairy, et al, 1987), the Dahab Formation is believed to be sandstone 
interbedded with claystone. This explains the considerable decrease of velocity in 
these areas. 
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260 
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..... 
LEGEND 
I. Faghur 13. Abu Tunis 
2. El Basour 14. El Ramis 
3. Faghur-E 15· Ghazalat 
4. Mamura 16. Meleiha 
5. Dawabis 17. Mideiwar 
6. Zayed 18. Mersa Matruh 
7. Urn Barka 19. Siqeifa 
8. Louly 20. Zarif 
9
· Abyad Zl. Mansour 
10. Kahraman 22· Yakout 
II. Khalda 23· Kheima 
12. Ghazalat-N o 24· Kanayis 
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LEGEND 
------
---------I -~ l MEDITERRA N E A N S E A I. Faghur i3. Abu Tunis 
- --~~~~-~ %'fo" I 2. El Basour '14. El Ramis I 3. Faghur-E 15. Ghazalat I 4 Mamura 16. Meleiha 5. Dawabis 17. Mideiwar 6. Zayed 18. Mersa Matruh 
7. Um Barka 19. Siqeifa ~ ;::~~ , .. 8. Louly 20. Zarif 9. Abyad 21. Mansour ~:.~~ 10. Kahraman 22. Yakout 11. Khalda 23. Kheima 12. Ghazalat-N 24. Kanayis o , Well Location ~ 010 Contour Line 3Joo Questionable Contour 
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M.D. EL-DAIRY, A.A. EL-SAYED, and M.A. EL-HEFNAWY 
Velocity gradient map of the Kharita Formation (Fig. 8) shows a systematical 
increase in velocity towards the northern direction of the study area. This may be 
due to the homogenity in lithofacies distribution of this formation which is 
composed of predominant sandstone with a few carbonate and shale streaks at the 
northern portions of the area. These streaks suffer from a rapid decrease as it is 
gone to the south direction. This can explain the general decrease in velocity 
gradient from the north to the south directions. 
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263 
00 
Petrophysical studies for some lower Cretaceous formations 
CONCLUSIONS 
1. The formation resistivity factor-porosity relations show the effect of conductive 
solids (kaolinite and illite), at different brine concentrations, on the multi-
plier(a) and cementation exponent(m) for the concerned rock samples. 
2. The (a/m) ratio could be considered as a lithofacies discriminating parameter, 
at certain formation water salinity, for the studied formations. It can easily 
performed for any sedimentary basin. 
3. The calculated saturation exponents(n) indicate that smaples, under investiga-
tion, are mainly water-wet (low saturation exponent). The saturation exponent 
measured in horizontal directions can be used for fluid saturation calculation in 
the concerned rock sequence. 
4. In general, it can be concluded that the high velocity can be attributed to 
massive rocks (carbonate or argillaceous sandstone rocks), while low velocity 
can be returned to loose rocks (mainly sandstones). 
ACKNOWLEDGEMENTS 
The authors are grateful to the authorities of the Egyptain General Petroleum 
Corporation (EGPC) for providing the necessary data. Financial support from the 
Egyptain Studentship Management is also gratefully acknowledged. 
REFERENCES 
Abdine, A.S. and Deibis, S. 1972. Lower Cretaceous Aptain sediments and their oil 
prospects in the North Western Desert of Egypt., 8th Arab Petrol. Cong., 
Algiers. 
Archie, G.E. 1942. The electrical resistivity logs as an aid in determining some 
reservoir characteristics., Trans., AIME. 146: 54-67. 
Barakat, M.G. and Arafa, A.A. 1981. Matruh shales contribution to their 
stratigraphy and sedimentary environment., Jour. Geol. Egypt. 25: 85-94. 
Barakat, M.G. and Darwish, M. 1984. Contribution to the lithostratigraphy of the 
Lower Cretaceous sequence in Mersa-Matruh area, North Western 
Desert, Egypt., 20th Ann.Mtg.Geol.Soc. Egypt (in press). 
Bussian, A.E. 1983. Electrical conductance in a porous medium, Geophysics, 48: 
1258-1268. 
Clavier, C., G. Coates and Dumanoir, 1977. The theoritical and experimental 
bases for the "Dual Water" model for the interpretation of shaly sands., 
52nd Ann Fall. Tech. Con. and Exhib. of SPE. 
264 
M.D. EL-DAIRY, A.A. EL-SA YEO, and M.A. EL-HEFNA WY 
El-Dairy, M.D. 1986. Geological and geophysical studies .on sol!le Lower 
Cretaceous sequences in the northern part of the Western Dese~t, Egypt. 
Ph. D. thesis, Ain Shams Univ, Cairo, Egypt. pp. 251. 
El-Dairy, M.D., El-Hefnawy, M.A. and El-Sayed, A.A. 1987. Structural elements 
and formation parameters for some Lower Cretaceous sequences in the 
Western Desert, Egypt, Qatar Univ. Sci. Bull. Vol 7. 
El-Gezzery, M.N., Mohsen, S.M. and Farid, M.I. 1972. Sedimentary basins of 
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B-3, 13pp. 
El-Sayed, A.A. 1987. Electrical properties of the Lower Eocene rocks in Qatar., 
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Fricke, H. 1924. A mathematical treatment of the electrical conductivity and 
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Hassan, N.M. 1969. Investigation of methods of measuring specific electrical 
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schemes., (in Russian) Petrofizika promyslovaya Geofizika, Moskova Inst. 
Neftekhim. I. Gazov. Promyshlennosti Trudy, 89: 5-12. 
Hassan, N.M. and El-Sayed, A.A. 1983. Electrical properties of Umm El-Yusr 
sandstone (Umm El-Yusr oil field) as an aid for determination of their 
storage capacity properties., 2nd Ann. Mtg. Egyptain Geophysical Soc. 2: 
86-107. 
Keelan, D.K. 1972. A critical review of core analysis techniques., Jour. of 
Petroleum Tech.: 42-55. 
Koithara, J,, Hashmy, K., Rawat, H. and Mehra, Y. 1965. Laboratory study for 
establishing the relationship between electrical and reservoir parameters of 
Ankleshwar productive sands., Bull. ONGC, India. 2: No.1. 
Metwalli, M.H., Philip, G. and Wali, A. 1979. Repeated folding and its 
significance in Northern Western Desert Petroleum province, ARE., Acta 
Geo. Polonica. 29: 133-150. 
Metwalli, M.H. and Abdel Hady, Y.E. 1973. Stratigraphic setting and lithofacies of 
the subsurface sediments in Alamein oil field, N.W.D., Cairo. Inst. 
Desert. Egypt. Bull. 2: No. 23. 
Metwalli, M.H. and Abdel Hady, Y .E. 1975. Petrographic characteristics of oil 
bearing rocks in Alamein oil field. significance of source reservoir relations 
in Northern Western Desert, Egypt., AAPG Bull. 59: 510-523. 
265 
Petrophysical studies for some lower Cretaceous formations 
Perez-Rosales, C. 1982. On the relationship between formation resistivity factor 
and porosity., SPE of AIME, Aug.: 531-536. 
Philip, G., Metwalli, M.H. and Wali, A. 1980. Cretaceous sandstone as oil and gas 
reservoir and their petrographic characteristics in northern Western 
Desert, A.R. Egypt., Acta Geo. Polonica. 
Wyllie, M.R.J. 1963. The fundamentals of well log interpretation., Academic 
Press, New York., pp. 238. 
266 
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