Geophysical, Geological Study and Hydrocarbon Habitat, Razzak Area, Western Desert, Egypt. Presented by. Mohamed Salah Sedek Abdel Hamed

Transcription

1 Geophysical, Geological Study and Hydrocarbon Habitat, Razzak Area, Western Desert, Egypt Presented by Mohamed Salah Sedek Abdel Hamed A Thesis Submitted to Faculty of Science In Partial Fulfillment of the Requirements for the Degree of Master of Science (Geophysics) Geophysics Department Faculty of Science Cairo University (2012)

2 APROVAL SHEET FOR SUMISSION Thesis Title: Geophysical, Geological study and Hydrocarbon Habitat, Razzak Area, Western Desert, Egypt. Name of candidate: Mohamed Salah Sedek Abdel Hamed This thesis has been approved for submission by the supervisors: 1- Dr. Mahmoud Aly Ghaleb. Signature: 2- Dr. Nadia Abdel Fattah. Signature: 3- Dr. Ali Mohamed Ali Bakr. Signature: Prof. Dr. Sharaf El Din Mahmoud Chairman of Geophysics Department Faculty of Science- Cairo University

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4 ACKNOWLEDGEMENTS Firstly and before all, my complete praise is for Almighty God, Allah, who guided and blessed me during the preparation of this work. I wish to express my sincere appreciation to: Prof. Dr. Sharaf El Din Mahmoud, Chairman of the Geophysics Department, Cairo University, for suggesting seismic as a suitable subject for scientific research in addition to his administrative supports and guidance. I am greatly indebted and thankful to my supervisors: Dr. Mahmoud Aly Ghaleb, His careful reading and revision of the manuscript contributed seriously to the release of this work in an acceptable form also suggestions including changes, additions, deletions and finding errors helped me so much during the different steps of writing this thesis. Actually, any kind of thank will not give him what he deserves. Dr. Nadia Abdel Fattah, For her immeasurable advising, consultation and encouragement. Her guidance and the scientific reviewing at all stages of this work improved my performance as much as it can not be forgotten. Her kind assistance is greatly appreciated. Dr. Ali Mohamed Ali Bakr, He suggested the plan of study and taught me the different aspects of seismic interpretation techniques. He provided me with the software and scientific researchers related to my study. My thanks and appreciated must be awarded to Mr. Samir Ahmed Abd El Aal; Geologist at Suez Oil Company (SUCO), Mr. Wessam AbdAllah; geophysicist at Gulf of Suez Petroleum Company ( GUPCO), Mr. Mohamed Sobhi; geophysicist at GUPCO Petroleum Company, for their help and fruitful discussion during the preparation of this thesis.

5 A.M.S.L: Above Mean Sea Level. Appendix List of Abbreviations API: American Petroleum Institute unit. ASCII: American Standard Code for Information Interchange. CCL: Creative Common License. FDC: Formation Density Compensated log. GNU: General Public License. GOR: Gas/Oil Ration. GR: Gamma Ray log. LAS: Log ASCII Standard file. LWD: Logging While Drilling. Md: Millidarcy. MMSTB: Million Stock Tank Barrels. OWC: Oil Water Contact. PSI: Pounds Per Squar Inch. SEGY: Society of Exploration Geophysics Y format (digital format). SNP: Sidewall Neutron Porosity log. SP: Self Potential log. SRD: Seismic Reference Datum. UTM: Universal Traverse Mercator (co-ordinate system).

6 Contents Chapter I : Introduction 1.1 Location Previous Work Exploration History Data Aim of Study Methodology 7 Chapter II : Geological Setting 2.1 Introduction Regional Tectonic Geotectonic Cycle Regional Structure Regional Stratigraphy of the Western Desert Depositional Basins Stratigraphy Local Stratigraphy of the Razzak Oil Field Structure of Razzak Oil Field Razzak Oil Field Reservoirs Exploration and Development Concepts 38 Chapter III : Well Log Analysis 3.1 Geophysical Logging Tools Electric Logs Induction Logs Nuclear Logs GR Log FDC log SNP log Acoustic Logs Sonic Log Well Logs Analysis Razzak Well RZK Razzak Well RZK Razzak Well RZK Razzak Well RZK Razzak Well RZK Razzak Well RZK i

7 3.3 Abu Roash G Petrophysical Characteristics Bahariya Formation Petrophysical Characteristics Alamein Dolomite Petrophysical Characteristics 77 Chapter IV : Seismic Interpretation 4.1 Acquisition Processing Synthetic Seismograms Razzak Well RZK Razzak Well RZK Seismic Interpretation Flowchart Well to Seismic Tie Picking and Tracing Fault Interpretation Digitizing Time Contouring Time-Depth Relation Seismic Interpretation Analysis of the top Alamein dolomite structure map 96 Chapter V : Seismic Vectorization 5.1 Introduction Seismic Vectorization Flowchart Editing Digitizing Base Map Digitizing Pixels Digitizing Parameters File Preparation SEGY OUT 103 Chapter VI : Structural Modeling 6.1 Introduction Modeling Process Flowchart Interpretation Process Seismic Horizon Interpretation Top Apollonia Formation Top Abu Roash G Formation Top Bahariya Formation Top Alamein Dolomite Formation Seismic Fault Interpretation Structure Time Contour Maps Using Fault Polygons 114 ii

8 6.4.1 Top Apollonia structure time map Top Abu Roash G structure time map Top Bahariya structure time map Top Alamein dolomite structure time map Structure Modeling Fault modeling Pillar gridding Velocity Modeling and Depth Conversion Depth Contour Maps Top Apollonia Depth Map Top Abu Roash G Depth Map Top Bahariya Depth Map Top Alamein Dolomite Depth Map Inter-Top Zonation Layering Final Model 129 Chapter VII : Integrating Results 7.1 Well Logging Results Seismic Data Analysis New Lead in Bahariya and Alamein Dolomite 143 Chapter VIII : Summary and Conclusion 146 References 150 iii

9 List of Figures Figure 1.1. Location map of the study area 1 Figure 1.2. Location map of the Razzak oil field 5 Figure 2.1. Regional tectonic of Egypt 10 Figure 2.2. The geotectonic cycles of Egypt 12 Figure 2.3. Motion between Africa and Laurasia 15 Figure 2.4. The regional structure framework of the Western Desert 16 Figure 2.5. The sedimentary basins located in the North Western Desert, Egypt 20 Figure 2.6. Stratigraphic section penetrating in North Western Desert of Egypt 23 Figure 2.7. Stratigraphic section penetrating in Razzak field 31 Figure 2.8. Razzak field complex main fields 35 Figure 3.1. Induction log equipment 40 Figure 3.2. Location map of Razzak wells 47 Figure 3.3. Razzak well no.01 showing the perforated interval related to Abu Roash G formation. 50 Figure 3.4. Razzak well no.01 showing both the top of the Bahariya formation and the first perforated interval which is at depth 5850 ft (1783m). 51 Figure 3.5. Razzak well no.01 showing the second perforated interval for the Bahariya formation wich is at depth 6137 ft (1871 m). 52 Figure 3.6. Razzak well no.01 showing the depth to the OWC related to the Bahariya formation along with both the porosity and water saturation values below the OWC. 52 Figure 3.7. Razzak well no.01 showing both porosity and water saturation values for the perforated intervals related to the Alamein dolomite formation. 53 Figure 3.8. Razzak well no.01 showing interested intervals above and below iv

10 the oil water contact related to the Alam El Buieb formation. 54 Figure 3.9. Razzak well no.03 showing both the of the Bahariya formation and perforated interval related to Abu Roash G. 56 Figure Razzak well no.03 showing both the oil water contact and the perforated intervals related to Alamein dolomite formation. 57 Figure Razzak well no.15 showing both the interested interval which is at depth 5780 ft ( m) related to Abu Roash G formation and the top of the Bahariya formation. 60 Figure Razzak well no.15 showing three interested intervals related to the Bahariya formation. 61 Figure Razzak well no.15 showing both porosity and water saturation (S W ) values below the Oil Water Contact (OWC) related to the Bahariya formation. 62 Figure Razzak well no.15 showing the interested intervals related to the Alamein dolomite formation. 63 Figure Razzak well no.17 showing four interested intervals related to the Bahariya formation. 65 Figure Razzak well no.17 showing both the depth to the OWC which is located at Burg El Arab formation along with the porosity and water saturation values below it. 66 Figure Razzak well no.19 showing three distinguishable intervals related to the Bahariya formation. 68 Figure Razzak well no.19 showing the depth to the OWC related to the Bahariya formation. 69 Figure Razzak well no.21 showing both the interested interval related to Abu Roash G formation and the depth to the top of the Bahariya formation. 71 v

11 Figure Razzak well no.21 showing both two interested intervals related to the Bahariya formation and the depth to the top of the Vraconian age. 72 Figure Razzak well no.21 showing the four interested intervals during the Vraconian age which is related to the Bahariya formation. 73 Figure Razzak well no.21 showing both the porosity and water saturation value at depth 6562 ft below the OWC related to the Alamein formation. 74 Figure The average water saturation and porosity of four studied Razzak wells of the Abu Roash G dolomite. 78 Figure The average water saturation and porosity of five studied Razzak wells of the Bahariya formation. 78 Figure The average water saturation and porosity of three studied Razzak wells of the Alamein dolomite formation. 78 Figure 4.1. Razzak oil field well No.15 synthetic seismogram 82 Figure 4.2. Razzak oil field well No.3 synthetic seismogram 83 Figure 4.3. Seismic interpretation workflow of the Alamein dolomite horizon. 84 Figure 4.4. Top Alamein dolomite time contour map 86 Figure 4.5. Relation between two way time in millisecond and the depth in feet using the available well data from both wells RZK-15 and RZK Figure 4.6. Top Alamein dolomite depth contour map 88 Figure 4.7. Seismic line RZ before seismic interpretation 90 Figure 4.8. Geoseismic cross-section of line RZ after seismic interpretation. 90 Figure 4.9. Seismic line RZ before seismic interpretation 91 vi

12 Figure Geoseismic cross-section of line RZ after seismic interpretation. 92 Figure Seismic line RZ before seismic interpretation 53 Figure Geoseismic cross-section of line RZ after seismic interpretation. 93 Figure Seismic line RZ before seismic interpretation 94 Figure Geoseismic cross-section of line RZ after seismic interpretation. 94 Figure Top Alamein dolomite structure time contour map 95 Figure 5.1. Seismic vectorization Flowchart. 98 Figure 5.2. Seismic line RZ showing two problems must be solved by the Editing process. 99 Figure 5.3. X and Y axis showing the UTM coordinates instead of latitude and Longitude coordinates system. 100 Figure 5.4. Seismic line RZ showing its pixels dimensions prepared for determine the pixel location for every 20 shot-point. 101 Figure 5.5. An example of how to write the required parameter file for converting the seismic image to SEGY format. 102 Figure 5.6. Seismic line RZ as displayed in PETREL interpretation window after a successful vectorization process. 103 Figure 6.1. Flowchart showing steps leading to the creation of the 3D model. 105 Figure 6.2. Arrangement of the vectorized SEGY seismic sections 106 Figure 6.3. Picking of top Apollonia formation 108 Figure 6.4. Top Apollonia time map 108 Figure 6.5. Picking of top Abu Roash G member 109 Figure 6.6. Top Abu Roash G time map 109 Figure 6.7. Picking of top Bahariya formation 110 Figure 6.8. Top Bahariya formation time map 110 vii

13 Figure 6.9. Picking of top Alamein dolomite 111 Figure Top Alamein dolomite time map 111 Figure 6.11 Qattara Alamein ridge. 112 Figure Seismic line RZ showing part of seismic fault interpretation Process. 113 Figure Seismic line RZ showing part of seismic fault interpretation Process. 113 Figure Top Apollonia time contour map. 114 Figure Top Apollonia structure time contour map. 115 Figure Top Abu Roash G time contour map. 115 Figure Top Abu Roash G structure time contour map. 116 Figure Top Bahariya formation time contour map. 116 Figure Top Bahariya formation structure time contour map. 117 Figure Top Alamein dolomite time contour map. 118 Figure Top Alamein dolomite structure time contour map. 118 Figure Fault modeling process. 121 Figure Pillar gridding (I and J direction applied) 122 Figure Linearization of instantaneous sonic velocities in borehole RZK Figure Location of both wells RZK-15 and RZK Figure Top Apollonia formation depth contour map. 127 Figure Top Abu Roash G depth contour map. 127 Figure Top Bahariya formation depth contour map. 128 Figure Top Alamein dolomite depth contour map. 128 Figure (A) Full 3D view of the created model. (B) Cross-section passing through the model in the middle of the Razzak oil field. 130 Figure Seismic cross-sections locations. 131 Figure Seismic cross-section (1). 132 viii

14 Figure Seismic cross-section (2). 132 Figure Seismic cross-section (3). 133 Figure Seismic cross-section (4). 134 Figure Seismic cross-section (5) 135 Figure 7.1. Razzak well RZK-15. Showing five tracks (from left to right): gamma ray (GR), porosity (NPHI), density(rhob), resistivity log (ILD) and sonic log (DT). 138 Figure 7.2. Geo-seismic cross-section RZK-06 with Razzak well RZK-15 projected on it. 139 Figure 7.3. Transcurrent motion between Africa and Laurasia. 140 Figure 7.4. Syrian Arc event. 141 Figure 7.5. Left lateral strike slip fault on coastal plan of Egypt. 142 Figure 7.6. Lead location map. 143 Figure 7.7. Lead passing through geo-seismic cross-section RZK Figure 7.8. Geo-seismic cross-section passing through the lead point. 145 List of Tables Table 3.1. The petrophysical characterized of the Abu Roash G dolomite 75 Table 3.2. The petrophysical characterized of the Bahariya formation 76 Table 3.3. The petrophysical characterized of the Alamein dolomite formation 77 Table 5.1. UTM system coordinates fro the area s base map. 100 Table 5.2. Seismic line RZ87-02 original pixels dimensions. 101 Table 6.1. V 0 and K values for the velocity modeling process and depth conversion. 126 ix

15 Chapter I Introduction 1.1 Location: Razzak oil field is located between latitude N and N and longitude E and E; north of Qattara depression, about 60 km south of the Mediterranean coast and about 150 km southwest of Alexandria city (Figure 1.1) it covers an area of about 105 km2 being 15 km long and 7 km wide (Zein El Din et al., 1982). Figure 1.1 Location map of the study area. It is one of the oldest oil fields in Egypt; it was discovered in February It lies in the northern half of the Western desert, where intensive exploration activities have been undertaken during the last 30 years. Almost 16% of Egypt s hydrocarbon production is generated from the Western Desert (Sestini, 1995). 1

16 1.2 Previous related work: The geology of the Western Desert in general has been the subject of numerous investigations since the end of the last century. The stratigraphy, structure, and geologic history have been investigated by many authors: Zittel, (1883); Beadnell, (1901, 1902, 1909); Krenkel, (1925); Hume, (1929); Sandford, (1934); Faris, (1948); Shata, (1953); Shukri, (1954); Knetsch, (1957 and 1958); Said and Barakat, (1959); Amin, (1961); Said, (1962); Awad and Ghobrial, (1966); Ghobrial, (1967); Gindy and El-askary, (1969); Barakat, (1970); Issawi, (1972); El Gezeery et al., (1972); Khaled, (1974); Metwalli and Abd El Hady, (1973, 1974, 1975); Saad and Ghazaly, (1976); Abu El Naga, (1984); Elzarka, (1983); Schrank, (1983); Penny, (1986); El Shamma, (1988, 1994); Taylor, (1984); Abdel Mohsen and Abdel Baset, (1988); Said, (1990); Soliman et al., (1991); Abdine et al., (1993); Sestini, (1995); Guiraud, (1998); MacGregor and Moody, (1998); Mahmoud et al., (1999); Mahmoud and Moawad, (2000, 2002); Mahmoud and Schrank, (2003); El Beialy, (2005); Abdou and Kassap, (2009). A brief mention for these works is included in the different chapters of this thesis. The most relevant studies to this scope of investigation are those undertaken in the neighboring areas dealing with the stratigraphic set up, structural elements and oil potentialities of some isolated and widely spaced oil fields in the central and northern parts of the Western Desert. 2

17 1.3 Exploration History: The first integrated and systematic hydrocarbon exploration program in the Western Desert was carried out in the mid-1950 by Sahara Petroleum Company (SAPETCO), which was given exploration rights over the entire 200,000 km2 northern Western Desert concession (Abdine, 1974). Razzak oil field was discovered as a result of an improvement of seismic reflections techniques which were introduced in 1960 to early According to Egyptian General Petroleum Company (EGPC), 1992: In January 1972, the first exploration well (NWD394-1) renamed RAZZAK-1 was drilled to test Alamein dolomite high structure. This well encountered 7 oil bearing zones. RZK-2 and RZK-3 were drilled to delineate this high structure. In June 1972, RZK -4 well was drilled to test another southwest Alamein high structure and put on production in July 1972, as Abu Roash G dolomite producer. Then RZK -5, 6, 7, 8 and 9 wells were drilled to fulfill the field development. In December 1972, RZK -10 well was drilled to test the northeast Alamein high structure in NWD 350 block. RZK -14 was the last well to be drilled in the area in August From March 1978 to December 1978, RZK-15 well was drilled in the East Razzak field to test northeast high structure in the Razzak block (NWD 350 block). It tested oil from the Abu Roash G and Bahariya and put on production in May 1978 as a Bahariya producer. In November 1988, the NWD well was drilled to test the upthrown side of the major NE-SW trending fault which is bounding the field to the north. It was classified as a dry hole with heavy oil shows within the Bahariya sand. 3

18 In February 1989, RZK -24 was drilled in the Razzak area as a water injector well for enhancing the productivity of the Abu Roash G dolomite in the west Razzak structure. This was followed by the drilling of a second water injector RZK -25 in March A maximum of 11 producing wells in West Razzak and Razzak Main were established during the period 1973 to mid These wells were classified as: 1- Bahariya producers (RZK-7, RZK -9, RZK -13, and RZK-14). 2- Abu Roash producers (RZK-4, RZK-12, RZK-13, and RZK-16). 3- Alamein producers (RZK-1, RZK-2, RZK-3, and RZK-5). [Note: RZK-13 produces from two formations Abu Roash G formation and Bahariya formation]. The entire Razzak field complex production rate in June 1988 is about 3900 barrel of oil per day. The overall production decline rate for Razzak Main and West Razzak is 23%, while East Razzak is 15% (Abdine et al., 1993). 1.4 Data: The data for the present study was provided by the Egyptian General Petroleum Corporation (EGPC) and the Gulf Of Suez Petroleum Company (GUPCO). It includes well logs and seismic sections. The well logs consist of six composite logs, six formation evaluation logs for wells (RZK-1, 3, 15, 17, 19 and 21) and two synthetic seismograms for Razzak wells RZK-3 and RZK15. The Razzak area (105 km2) is covered by 30 seismic sections (From RZ87-1 to RZ87-32), 16 seismic sections with NE-SW which are (RZ87-02, RZ87-04, RZ87-06, RZ87-08 to RZ87-32). The remaining 14 seismic sections are with NW-SE trend which are (RZ87-01, RZ87-03, RZ87-05, RZ87-07 to RZ8727) (Figure 1.2). 4

19 Figure 1.2 Location map of the Razzak oil field. showing wells and seismic section lines. 5

20 1.5 Aim of Study: The aim of the present study is to investigate the role and effect of tectonic and structure processes on oil accumulation of the Alamein dolomite, petrophysical study and to create a 3D geological model of the main hydrocarbon habitats located in the Razzak oil field. This investigation includes Abu Roash G dolomite, Bahariya formation and the Alamein dolomite. And to integrate between the seismic interpretation, modeling and the petrophysical results to delineate a new lead in the Razzak oilfield. Investigating the Alamein dolomite formation gives valuable information about the local geologic structures (as it is considered a strong reflector) and tectonic forces that affected the Razzak oil field thus creating a more reliable 3D model and matching with the major regional tectonic events. The 3D geological model starts from top Apollonia to the top of the Alamein dolomite. 6