1. بسـم الله الرحمـن الرحـيم Fouad Shaaban, Hamdy Seisa, and Mohamed Awad
Reservoir Characterization and Hydrocarbon Potentialities of the Qawasim and Sidi Salim formations, NE Nile Delta
Fouad Shaaban, Hamdy Seisa, and Mohamed Awad
Geology Dept., Faculty of Science, Mansoura University, Mansoura, EGYPT

2. Objectives
To give a proper appraisal on the subsurface geologic context integrated with a comprehensive reservoir characterization of the Sidi Salim and Qawasim formations in the northeastern part of the Nile Delta and evaluate their hydrocarbon potentialities.

3. Materials
Borehole information and complete set of wireline logs of 23 off- and onshore wells, NE Nile Delta
An interactive formation evaluation software “IP”

4. Location map Lat: 30° 50’ & 31° 55’ N, Long: 31° 12’ & 32° 36’ E
Index map showing geographical location of the investigated site (marked by the square) relative to the whole country of Egypt, with the associated spatial distribution of the available drilled holes used. The drilled holes belonged to different companies concessions and were drilled in the period between 1968 and 1985.

5. Goals I- Subsurface Geological investigation
1) Extract a complete subsurface geo-information from the borehole data such as composite logs.
2) Identify meaningful stratigraphic mapping horizons in the studied formations.
3) Recognition of unconformities and stratigraphic discontinuities.
4) study of the structural framework and its influence on the hydrocarbon entrapment.

6. II- The Reservoir Characterizations
Goals (Continued)
II- The Reservoir Characterizations
Encompasses quantitative determination of the reservoir limits, heterogeneity, reservoir properties and define reservoir continuity for:
1) Evaluating the distribution and lithological characteristics of the studied formations.
2) Identification of the clay mineralogy (percentages and types).
3) Determining the petrophysical characteristics of the studied formations.
4) Mapping the reservoir parameters
5) Build appropriate reservoir models.
6) Recommend new well locations.

7. III- The hydrocarbon potentialities
Goals (Continued)
III- The hydrocarbon potentialities
1) Develop facies interpretations for correlation at the developmental scale.
2) Determine facies controls on reservoir quality and (dis)continuity
3) Delineate reservoir heterogeneities, identify individual rock types, and evaluate the distribution of the remaining reserves.
4) Modeling the inter-well space on the basis of the petrophysical well information.

8. Geological Investigation

9. General geological setting of the studied formations
Sidi Salim Formation (Middle-Late Miocene)
- composed of predominant shale intercalated with streaks of quartzose sandstone with occasional sandy limestone at its top.
Qawasim Formation (Late Miocene)
- composed of thick layers of sands, sandstones interbedded with clay layers.
- stratigraphically the Qawasim Formation is equivalent to the Wakar Formation.

10. Lithostrati- graphic framework of the Nile Delta area (Schlumberger, 1984)

11. Isopach contour map of the Sidi - Salim Formation.
Regular thickness contour pattern increases generally maxi. thickness 1499 m at the Ras El-Barr offshore well # 1. The mini. 110 m at the Rommana well # 1.
The formation is not totally penetrated at the onshore wells (Abu Madi well # 3, El-Qar'a well # 1, El-Wastani well # 1, Khilala well # 1, and Tell El-Ahmar well # 1) and the offshore wells (Ras El-Barr offshore well # 1 and Matariya well # 1). This means that the encountered thickness values of these wells represent the maximum drilled thickness of the Sidi Salim Formation not its true thickness.
The Sidi Salim Formation is completely missed at the offshore Kersh well # 1 and the onshore at Mallaha well # 1, but, not totally penetrated through at the offshore Damietta well # 1.l part.

12. Sand/shale ratio contour map of the Sidi Salim Formation.
irregular contour pattern closely occupies the onshore parts with an increasing direction S and W wards recording maxi. ratio of 1.17 at Abu Madi well # 3.
This pattern decreases offshore ward recording the minimum ratio value of 0.02 at the Ras El-Barr well # 1. The two abnormal (onshore) high ratio anomalies at the Tarif well # 2A and the Abu Madi well # 3 suggest a prograding delta and transgression channel environment at the southwestern part to marine environment towards the north and northeast offshore parts.

13. Isopach contour map of the Qawasim Formation.
appears to be influenced by the underlying paleorelief of the Sidi Salim Formation.
The maximum recorded thickness is 1026 m at the Matariya well # 1.
The minimum thickness is 71 m at El-Qar'a Well # 1, while the formation is completely missed at the offshore Temsah well # 2.
This thickness pattern appears to be mainly controlled from the southern part by the hinge line and by the Misfaq-Bardawil line from the NE direction

14. Sand/shale ratio contour map of the Qawasim Formation.
The maxi. ratio of 1.12 recorded at the Rommana well # 1X.
The relatively high ratio at the Rommana well #1, Tarif well # 2A, and Bilqas South West well # 1 suggest a prograding Delta and transgression channel environment onshore area to marine environment towards the northern and northeastern offshore parts.

15. Structural Framework
The subsurface structural setting of the studied area has been studied using a number of structural maps and cross sections, illustrated by the following:

16. Structural contour maps on the top of the Sidi Salim Formation
-influenced by the Pre-Miocene set of faults running NE-SW and NW-SE with a general throws NW, NE and northwards, with throw magnitudes ranging from <200 - >600 m.
This is gave rise to different sites of structurally low areas that generally restricted to the N, NE and NW-offshore parts of the area.
The structurally highs occupy the S onshore parts of the area.
throw magnitudes of these faults are To NE, abnormal throw (>1000 m) is found along fault trace (NW-SE) (equivalent to Misfaq-Bardawil line).

17. Structural contour maps on the top of the Qawasim Formation.
irregular paleo-relief pattern dipping generally N and NW-wards and dissected by NE-SW and NW-SE trending faults. The throw magnitudes of these faults ranging from <350 m at the Hinge line to >400 m at the Misfaq-Bardawil line. These throws are much larger in the Sidi Salim Formation than those of the overlying Qawasim Formation, which indicates that these faults are older in age than the Qawasim Formation and periods of rejuvenations may occur along these faults.
The central part of the area (around the Manzala Lake) is characterized by smooth, gently dipped relief, which indicates the lack of major faulting in that area.

20. Tectonic Framework

21. Reservoir Characterizations Using Wireline LogsII
Reservoir Characterizations Using Wireline Logs

22. Objectives of the well log analysis
Determination of:
Volume of shale and total porosity
Water and hydrocarbon saturations
Reservoir, pay zone parametrs
Cutoff summary.

23. Data Preparation and Processing
Depth-matched readings to ensure that the log readings are on-depth relative to each other.
Digitizing the roster formatted log responses as functions with depth. The values represent the raw INPUT for the used "Interactive Petrophysics" (IP) log analysis software.
Environmental corrections for the well logging data.
Determination of the representative petrophysical model as follow:
1) Using both single and double shale indicator to compute volume of shale for the zones of interest.
2) Perform a simple shale correction, to improve the estimate of the total porosity, effective porosity, and fluid saturation.
3) Assume a dual mineral (shale and matrix), single fluid (water) model for each of the basic lithologies, compute the porosity.
4) Reasonable cutoffs were chosen from experience in sands and hydrocarbon summaries. The zones that passed all chosen cutoffs parameters are flagged on the depth plots.

24. Shale Volume Determination
Single indicator
Double indicator

25. Shale Distribution mode
A. Dispersed
C. Structural
B. Laminated
Clay
Sand

26. Shale Distribution Mode from the Neutron/Density porosity crossplot.

27. Porosity Type deduced from Neutron-Density/ Sonic porosity crossplot of the studied interval

28. Vertical (zone wise) presentation of the “IP” Input/Output data
Dealing with 23 wells represented in two separate crossplots.
1- The first one represent the corrected data sets,with the resultant volume of shale.
2- The second, displays the litho-saturation crossplot.
The petro-lithofacies annotations, represent specific lithological and saturation conditions as follow:
Letter "A" points to a clean sand zone of Vsh < 10%,
Letter "B" points to a silty sand zone of Vsh <10%,
Letter "C" points to a sand zone with Vsh values ranging from 10% to < 35%,
Letter "D" points to a sand zone of Vsh > 35% (shale zone).
These letters post-scripted by the number 1, or 2 or 3. Moreover, the letter Q or S is added to the zone annotations to indicate Qawasim (or Wakar equivalent) or the Sidi Salim formations, respectively.
In general, the hydrocarbon prospective bearing zones are annotated A1, B1, or C1, prospective reservoir characterization only are denoted A2, B2, or C2.

30. Reservoir zones characterizations
Volume of shale and total porosity
Water and hydrocarbon saturation
Net reservoir and net /gross ratio

31. Net reservoir (a) and net/gross ratio (b) maps of Qawasim Formation
(a) (b)

32. Net reservoir and net/gross ratio maps of the Sidi Salim Formation
(a) (b)

33. Volume of shale and total porosity maps of the Qawasim Formation
(a) (b)

34. Volume of shale and total porosity maps of the Sidi Salim Formation
(a) (b)

35. Water and hydrocarbon saturation maps of the Qawasim Formation
(a) (b)

36. Water and hydrocarbon saturation maps of the Sidi Salim Formation
(a) (b)

37. Pay zones characterizations
Volume of shale and effective porosity
Total and movable hydrocarbon saturation
Net pay and net pay/gross ratio

38. Volume of shale and effective porosity maps of the Qawasim Formation
(a) (b)

39. Volume of shale and effective porosity maps of the Sidi Salim Formation
b.)
(a) (b)

40. Total and movable hydrocarbon saturation maps of the Qawasim Formation

41. Total and movable hydrocarbon saturation maps of the Sidi Salim Formation

42. Net pay and net pay/gross ratio maps of the Qawasim Formation
(a) (b)

43. Net pay and net pay/gross ratio maps of the Sidi Salim Formation
(a) (b)

44. The hydrocarbon potentialities
III
The hydrocarbon potentialities

45. The Pie chart map of the Qawasim Formation
Shows sand matrix (>50%), intercalated with 25% clay content.
The effective porosity is <25% and
1-totally saturated with water SE of the Rommana, Qantara South, and Port Said South.
2- A considerable amounts of hydrocarbons (gas and /or condensate) and residuals are recorded N ward in the offshore wells.

46. The Pie chart map of the Sidi Salim Formation
Shows the dominance of clay and silt (>75%). The measured porosities are affected by the high clay content.
A considerable amount of hydrocarbons are recorded NE and SE wards, the majority is residual with few movable habit (gas and /or condensate), especially at the offshore wells.

47. Lease maps of the Qawasim Formation

48. Lease map of the Sidi Salim Formation
b.)
Lease map of the Sidi Salim Formation

49. Conclusions
Wireline and composite logs of 23 wells distributed NE Nile Delta have been used in an intergrated geological/petrophysical study for evaluating the hydrocarbon potentialities of the Qawasim and Sidi Salim fromations.
The Cutoffs and Summation report allows to define cutoffs, and to calculate the average petrophysical properties for each pay zone parameters.
The Qawasim Formation lease map reveals that the Manzala Lake and its opposite offshore parts are considered as the most prospective sites in the study area. Nevertheless, the pay lithofacies properties of these sites are of B1 and C1 types, they have the maximum pay thickness that ranging from <5m NE and SW wards up to >50m at the central Manzala Lake. However, the hydrocarbon distinguished is mainly of condensate habitat. At the extreme northeastern part of the study area a considerable thickness of pays are recorded with lithofacies mainly of A1 with B1 and C1 types. The hydrocarbons of these pays are mainly of gaseous habitat. South and NW wards of the area, no hydrocarbon shows have been recorded.
By contrast, the lease map of the Sidi Salim Formation, indicates no considerable pay zone thicknesses in the entire onshore area.This is mainly due to its lithological characteristics (D3 types) that mainly composed of clay or shale with very fine sand and silt matrix. To the northeastern offshore part of the area, a considerable pay zone thickness has been recorded, ranging from 5 m up to 40 m seaward with mainly A1 lithofacies type and condensate hydrocarbons, become of gaseous phase northward. Local pay thickness is recorded locally towards the southern, southeastern, and western parts of the area, with not less than 5 m thickness saturated by condensate and gaseous hydrocarbons. The lithotypes of these local occurrences are mixtures of A1, B1 and C1 zone types.

50. Recommendations
1. More attention should be given to the formations studied by using the newly developed seismic technology, particularly 3D seismic, 2D & 3D (AVO) and bright spots. These top technologies provide powerful tools for understanding the reservoir characterization, the complex faulting distribution in the subsurface and in reducing risk of drilling dry holes.
2. Further exploratory wells are recommended for drilling in the offshore area, north and in the Manzala Lake, where a considerable thickness of pay zone is recorded.

51. Thank you
For your attention

52. Questions