1. بسم الله الرحمن الرحيم
صدق الله العظيم

2. Welcome to M. Sc. Discussion invitation
Mohammed Awad Ahmed
Mansoura University
Faculty of Science
Geology Department
2002

3. Thesis Title
Petrophysical Characteristics and Hydrocarbon Potentialities of the Subsurface Miocene Reservoirs in the Northeastern part of the Nile Delta, Egypt; Using Borehole Geophysics

4. SUPERVISORY COMMITTE Prof. Dr. Mohammed Refaat Sherief
Professor of Applied Geophysics
Prof. Dr. Fouad Fawzy Shaaban
Professor of Well logging and Geoelectric
Dr. Hamdi Hamed Seisa
Assistant Professor of Applied Geophysics

5. REFREE COMMITTE Prof. Dr. Nasar M. H. Abu Ashour Ain Shams University
Professor of Petrophysics
Ain Shams University
Prof. Dr. Nadr H. Taha El - Gendi
Professor of Petrophysics & well logging
Tanta University

6. General Construction Introduction General Geological Setting
Borehole Geophysics
Data processing and interpretation
Results and Discussions
Conclusions and Recommendations

7. Chapter One
Introduction

8. Goals
Using well logs data to interpret the geologic situation integrated with a reservoir petrophysical characterization pointed to evaluate the hydrocarbon potentialities of the Sidi Salim and Qawasim (Wakar) Formations.
Amenable aims:
1-2.1 Geologic investigations
- studying previous publications and geologic information dealing with, regional setting (structures, stratigraphic sequence and geologic history)
Stratigraphic sequence – based studies
lateral extensions of both reservoir and non-reservoir facies, as well as the distribution of reservoir properties for:
1) Recognition of unconformities and stratigraphic discontinuities.
2) Extract a complete subsurface geo-information from well logging data and related geologic data such as composite logs.
3) Develop facies interpretations for correlation at the development scale.
4) Determine facies controls on reservoir quality and (dis)continuity
5) Delineate reservoir heterogeneities, and evaluate the distribution of the remaining reserves.
6) Modeling the inter-well space on the basis of the petrophysical well information.

9. Goals (cont.) 1-2.2 Borehole geophysical investigations
1) Determining the petrophysical characteristics of the studied formations.
2) Identification of the clay (percentages and mode of distribution).
3) Evaluating the distribution and lithological characteristics of the penetrated sequence.
4) Mapping the reservoir parameters (thickness, hydrocarbon pore volume).
1-2.3 Matching petrophysical results to geologic model
a. Petrophysical-geologic maps:
Documentation maps, Derived maps, Structure contour maps, Isopach map.
b. Geologic cross sections:
1-2.4 Integrated reservoir characterization
quantitative determination of reservoir limits, structure, heterogeneity, and reservoir properties (net and gross reservoir thickness, water saturation, porosity, matrix density, and permeability).
(maximize production, extend life of fields, describe and understand porosity types and effectivness, and define reservoir continuity).
1) Build appropriate reservoir models.
2) Recommend new well locations.
3) Reduce uncertainties in reservoir modeling.

10. Material & methods 1-3.1 Reservoir characterization achievement
subsurface borehole geological and well logging data of 23 wells to verify the following:
1-3.1 Reservoir characterization achievement
log evaluation; lithology and fluid analysis;
forward modeling; rock property relationships;
cross-plotting; and rock property estimation.
1-3.2 Computerized processing and modeling including different crossplots
1) Filter the raw log response data to correct anomalous data points.
2) Normalize logs to determine the ranges for porosity, clay content, water resistivity
3) Correct neutron, sonic, density and resistivity logs for mud filtrate invasion
1-3.3 Petrophysical data gathering for integrated study
1) Geological data on depositional environment, structural geology.
2) Geological cross-sections and formation descriptions.
3) Structure map with well locations, faults.
4) Porosity, saturation, net pay, pore volume and hydrocarbon saturation
5) Different sets of the borehole geophysical database.

11. General Geologic Setting
Chapter Two
General Geologic Setting

12. Location map 30° 50’ & 31° 55’ N, 31° 12’ & 32° 36’ E area of 20420 Km2.

13. Litho-Stratigraphic Framework of the Nile Delta area

14. Studied Intervals Sidi Salim Formation (Middle-Late Miocene)
- composed mainly of shale intercalated with streaks of sandstone (of calcareous cement) with occasional sandy limestone at its top.
Qawasim Formation (Late Miocene)
- composed of thick layers of sands, sandstones, and conglomerates, interbedded with clay layers.
- sandstone is ill-sorted, and cemented by clayey cement.
- stratigraphically the Wakar Formation is equivalent to the Qawasim Formation.

15. Structural contour map on the top of the Sidi Salim Formation
-influenced by Pre-Miocene faults NE-SW and NW-SE with a general throws NW, NE and northwards.
Resulted in different sites of structurally low areas restricted to N, NE and NW -offshore parts.
Structurally highs occupy southern onshore parts of the area.
The throw ranging from <200 - >600 m. The max throws detected at southern part due to the effect of the southern fault trace (Hinge Line that affecting the Pre-Miocene formations).
To northeastern, abnormal throw (>1000 m) found along fault trace (NW-SE) (Misfaq-Bardawil line).
minor throws (<200 m) recorded along minor fault traces in the central part.

16. thickness (Isopach) contour map of the drilled Sidi Salim Formation.
a regular thickness contour pattern increases generally northward max 1499 m at the Ras El-Barr well # 1.
This pattern decreases gradually to the south, east and westwards, min of 110 m at the Rommana well.
The whole thickness is not totally drilled that means the encountered thickness values of these wells represent the maximum drilled thickness not true thickness.

17. Sand/shale ratio contour map of the Sidi Salim Formation.
irregular contour pattern occupies the onshore parts with increasing direction south and westwards max 1.17 at Abu Madi well # 3.
This pattern decreases offshore ward mini 0.02 at Ras El-Barr well # 1.
The two abnormal (onshore) high ratio at Tarif well # 2A and Abu Madi well # 3 suggest a prograding delta and transgression channel environment at the SW part to marine environment towards the north and northeast offshore parts.

18. Structural contour map on the top of the Qawasim Formation.
irregular paleo-relief pattern dipping north and NW-wards that dissected by a number of faults running NE-SW and NW-SE directions.
The throw ranging from <350 m at the Hinge line to >400 m at the Misfaq-Bardawil line. The throw direction is N, NE and NW-wards.
these faults are those affected Sidi Salim Formation, but with different throw magnitudes of the same faults. These throws are much larger in the Sidi Salim Formation than those of Qawasim Formation. This indicates that these faults are older in age than the Qawasim Formation and periods of rejuvenations may occur along these faults.

19. Gross thickness (Isopach) contour map of the Qawasim Formation.
influenced by paleorelief of the Sidi Salim Formation, The thickness increases at the central part, and northeast ward, max 1026 m and 1013 m at the Matariya well # 1 and the Wakar well # 1 St.2.
These thicknesses decrease from the central and the northeastern parts, outwards in all direction, min 71 m NW ward at El-Qar'a Well # 1, while completely missed at the offshore Temsah well # 2.

20. Sand/shale ratio contour map of the Qawasim Formation.
irregular distribution allover the area with increasing direction SE, S, N and W, max 1.12 at the Rommana well # 1X.
min < 0.01 at the Qantara South well # 1, NE of the Manzala Lake and N Abu Madi (offshore area).
The abnormally onshore high at the Rommana well #1, Tarif well # 2A, and Bilqas South West well # 1.
Abdel Halim (2001) stated that the high ratio values at the Ras El-Barr offshore well # 1 indicated a deeply buried channel environment.
the huge thickness at central part, has low sand/shale <0.5 which diminishes to <0.1 at the NE and NW offshore parts. This delineates coarsening in the sequence at Rommana well # 1, via silt to clay north ward and northeast wards.

21. Mainly continental environment with marine to fluvitaile phases.
Th/U ratio crossplot versus depth of the Khilala well # 1. The data obtained from the NGS log opposite the Qawasim and Sidi Salim Formations.
Qawasim Formation
Sidi Salim Formation
Mainly continental environment with marine to fluvitaile phases.
Mainly marine environment with mixed and continental environmental phases
a rough environmental indicator has been achieved through analysis of the NGS log in the Khilala well # 1 The crossplot of Th/U ratio versus depth indicates presence of unconformity surface separating the Qawasim and Sidi Salim Formations that attain different Th/U patterns.
the Th/U ratio ranges that characterized the different depositional environments (Rider, 1996), the Qawasim Formation appears to be deposited under marine environment with mixed and continental phases.
By contrast, the Sidi Salim Formation appears to be deposited under continental with marine to fluvitaile phases.

22. Tectonic Framework

23. Cross-section illustrate the downhole information for the individual wells. The section pathway panels ( ).

24. Cross-section

25. Cross-section

26. Structural Framework
The subsurface structural setting of the studied interval:
a) Sidi Salim basin of rough topography that affected by Pre-Sidi Salim (faulting). Accordingly, the thickness of the Sidi Salim Formation is strongly variable.
b) Syn-Sidi Salim (faulting) are also recorded which gave rise to strong variations of its thickness on both sides of the faults passing through it. This is may attributed to rejuvenation of these syn-depositional faults.
c) Qawasim Fm. usually unconformably overlies Sidi Salim Fm. but the Sidi Salim Fm. occasionally thins (e.g. at Rommana and Qantara, and Port Fouad Marine and Wakar wells) or completely disappear (e.g. at Mallaha well and Kersh well) gave rise to Qawasim Fm. overlies, unconformably the Pre-Sidi Salim Fm. This indicates the post- Sidi Salim faulting and erosion of the highly faulted-up thrown blocks relative to the down thrown–faulted blocks.
d) A common unconformity is suggested between the studied formations due to the strong variation in their thickness along both sides of the fault planes. Evidence of this event is declared based on paleontological assemblages in the composite log of the studied wells.
e) The Late Miocene Qawasim Fm. is generally variable in thickness due to the irregular topography of the Middle Miocene Sidi Salim Fm. The deposition of the Qawasim Fm. appears to be associated with a marked syn-depositional faulting that gave rise to sculpturing the relief of the Post Miocene sediments.

27. Borehole Geophysics (Basic concepts)
Chapter Three
Borehole Geophysics (Basic concepts)

28. The Definition of Petrophysics
“ Petrophysics is the synergistic process of integrating multiple disciplines to characterize rock, pore and fluid systems ”

29. Procedures Volume of Shale Determination
Setup the model used (clean or shaly model)
Porosity and Water saturation
Cutoff summary.

30. Shale Volume Determination
Single indicator
Double indicator

31. Data Processing and interpretation
Chapter Four
Data Processing and interpretation

32. Data Processing
Typical log suite included cal, Res, Den, Neu, sonic, GR, and composite logs.
depth-matched readings to ensure that they are on-depth relative to each other.
digitizing the roster-formatted logs. First, splitting the interested interval into zones of different log responses, and then digitizing these responses as functions with depth. These log data represent the raw INPUT for the used "Interactive Petrophysics" (IP) log analysis software.
Borehole environmental corrections. In order to predict accurate values of total and effective porosity, types of pore fluids and saturations.
All the available geological and log data were utilized for determination of the most representative petrophysical model as follow:
1) single and double shale indicator to compute volume of shale.
2) Assume a dual mineral (shale and matrix), single fluid (water) model, compute the porosity log from density-neutron module and /or sonic model.
3) Perform a simple shale correction, to improve the estimate of the total porosity, effective porosity, and fluid saturation.
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.

33. Vertical (zone wise) presentation of the formation evaluation results
Dealing with 17 wells each one represented in two separate crossplots. First crossplot represents the borehole environmental corrected data sets, accompanied with the resultant volume of shale. Second crossplot, display the Zonation used, porosity and water saturation, cutoff, reservoir and pay flag, and the petro-lithofacies annotation.
These letters represent specific lithological and saturation conditions as follow:
Letter "A" a clean sand zone of Vsh < 10%,
Letter "B" a silty sand zone of Vsh <10%,
Letter "C" a sand zone with Vsh 10% - < 35%,
Letter "D" a sand zone of Vsh > 35% (shale zone).
letter Q or S indicate Qawasim (or Wakar equivalent) or the Sidi Salim Formations.

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

36. Shale Distribution Mode Neutron/Density porosity crossplot of the clean and clayey zone within the studied interval.

37. Porosity Type effect Neutron-Density/ Sonic porosity crossplot of the studied interval

38. Overestimated porosity
Total Porosity versus Depth Neutron-Density porosity versus depth crossplot of the studied interval
Normal Trend
Overestimated porosity
due to shale effect
Shale or clay porosity
Normal Trend

39. Sonic log versus Depth Sonic interval transit time versus depth crossplot of the studied interval,
Normal Trend
Qawasim
Formation
Sidi Salim

40. Results and Discussion
Chapter Five
Results and Discussion

41. Spatial distribution of the formation evaluation parameters
The aerial distribution of the derived parameters attained for Qawasim and Sidi Salim Formations are represented by different maps that shows,
Reservoir Characterizations
Pay zone Characterization

42. I-Reservoir Zone Characterization
Net reservoir and net/gross ratio maps
volume of shale and total porosity maps
water and hydrocarbon saturation maps

43. II-Pay Zone Characterization
Net pay and net pay/gross ratio maps
Volume of shale and effective porosity maps
Total and movable hydrocarbon saturation maps

44. Reservoir characterization maps
Qawasim Formation Sidi Salim Formation

45. Net reservoir and net/gross ratio maps of Qawasim Formation

46. Net reservoir and net/gross ratio maps of the Sidi Salim Formation

47. Volume of shale and total porosity maps of the Qawasim Formation

48. Volume of shale and total porosity maps of the Sidi Salim Formation

49. Water and hydrocarbon saturation maps of the Qawasim Formation

50. Water and hydrocarbon saturation maps of the Sidi Salim Formation

51. Pay zones characterization maps
Qawasim Formation Sidi Salim Formation

52. Volume of shale and effective porosity maps of the Qawasim Formation

53. Volume of shale and effective porosity maps of the Sidi Salim Formation
b.)

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

55. Total and movable hydrocarbon saturation maps oof the Sidi Salim Formation

56. Net pay and net pay/gross ratio maps of the Qawasim Formation

57. Net pay and net pay/gross ratio maps of the Sidi Salim Formation

58. Petrophysical integration process
Qawasim Formation Sidi Salim Formation

59. The Pie chart map of the Qawasim Formation
sand matrix (>50%), intercalated with 25% clay content.
Effective porosity <25% which are:
1-totally saturated with water at SE (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.

60. The Pie chart map of the Sidi Salim Formation
The dominance of clay and silt (or very fine sand) materials (>75%).
The porosities are affected by the high clay content giving rise to overestimation of the matrix porosity.
A considerable amount of hydrocarbons are recorded NE and SE wards.

61. Conclusions and Recommendations
Chapter Six
Conclusions and Recommendations

62. Conclusions The main conclusions:
The lack of adequate density and neutron log data prevents the calculation of porosity corrected for heavy minerals.
The high GR readings indicate either feldspathic sands, or other radioactive rock fragments. (Affect the calculation of shale content).
Conventional log datasets were incorporated in IP-evaluation. That yielded the most reliable answers regarding lithologies, effective and total porosity, hydrocarbon reserves.
The main reason for low resistivity pay in the Nile Delta Miocene reservoirs is the fine grained nature which can hold high amount of irreducible water beside the presence of the clay minerals
The effect of a gas phase in porosity within the silt component of the shale cannot be accounted for, even if it were known to be present. Invasion by drilling fluid removes most of the gas from the region seen by the sonic log, so the effect should be very small. A well log model study could be undertaken to assess the magnitude of gas effect.

63. Technical Recommendations
1. A study should be undertaken to map water resistivity versus depth, since no Rw data was provided for this project.
2. In future drilling, conventional and special core analysis should be conducted to obtain capillary pressure and electrical properties to help calibrate water saturation.
3. Re-compute log analysis with a complex lithology model using a zoned ρma value to correct porosity for heavy minerals.

64. Developmental Recommendations
1. The lease maps of the Qawasim and the Sidi Salim Formations should be seriously taken into consideration in the future exploration work in the investigated area.
2. More attention should be given to the formations studied by using the newly developed seismic technology. 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.
3. 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.

65. Lease maps of the Qawasim Formation

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

67. Dedication
Gratefully and respectfully dedicated to my Father, whose encouragement inspired me, (He thought that I can make a contribution and I eventually did !)

68. Thank You for your attention and consideration
Thanks
Thank You for your attention and consideration

69. Questions & Comments