1 Alam El Bueib Reservoir Characterization Student Name Mahmoud A. Mohamed, Omar Y. Sayed, Mohamed K. Mohamed, Mohamed S. Ramadan, Omar S. Ali and Mohamed S. Ali Department of Geology, Alexandria University PG207: Seminar Series Dr. Abd El - Aziz Alaa May 26 ,2025 2 Table of Contents Abstract ................................ ................................ ................................ ................................ ......... 10 Introduction ................................ ................................ ................................ ................................ ... 11 1.1. The Western Desert’s Major Province ................................ ................................ ............... 14 1.2 General Lithostratigraphy of the Western Desert ................................ ............................... 15 2. Tectonics and Structural Fe atures of The Western Desert ................................ ........................ 16 2.1. Early Mesozoic Tethyan Rifting ................................ ................................ ....................... 16 2.2. Cretaceous Rifting ................................ ................................ ................................ ............ 16 2.3. Late Cretaceous to Recent TethyanConvergence ................................ .............................. 16 2.4. Structural Features of the Western Desert ................................ ................................ ........ 20 2.4.1. The Kattaniya inverted basin ................................ ................................ ..................... 20 2.4.2. Mubarak Inverted Basin ................................ ................................ ............................. 20 2.4.3. Inverted Structures within Abu Gharadig Basin ................................ ........................ 21 2.4.4. Nubia Fault System ................................ ................................ ................................ .... 21 3. Sedimentary Basins in the Western Desert: Alam El Bueb Case Study ................................ .. 22 3.1. Basins ................................ ................................ ................................ ................................ 22 3.1.1. The Matruh Basin. ................................ ................................ ................................ ...... 22 3.1. 2. Abu Garadig Basin ................................ ................................ ................................ ...... 22 3.1.3. Shushan Basin ................................ ................................ ................................ ............ 24 3.1.3.1. Burial History of Shoushan Basin ................................ ................................ ........ 24 3.1.3.2. Cycles of Shoushan Basin ................................ ................................ .................... 24 4.Stratigraphy ................................ ................................ ................................ ................................ 26 4.1. The stratigraphy succession can be divided into four unconformity bound cycles each terminated by a marine transgression (Sultan and Halim, 1988) ................................ .............. 27 3 4.1.1. First cycle ................................ ................................ ................................ .................... 27 4.1.2. Second cycle ................................ ................................ ................................ .............. 27 4.1.3. Third cycle ................................ ................................ ................................ .................. 28 4.1.4. Fourth cycle ................................ ................................ ................................ ................ 29 4.2. Western desert stratigraphic column ................................ ................................ .................. 30 4.3. LITHOSTRATIGRAPHY FORMATION ................................ ................................ ........ 30 4.3.1. Paleozoic ................................ ................................ ................................ ..................... 30 4.3.2. Jurassic ................................ ................................ ................................ ........................ 30 4.3.2.1. Ras Qattara Formation (Lower Jurassic) ................................ ............................. 31 4.3.2.2. Khatatba Formation (Middle Jurassic) ................................ ................................ 31 4.3.2.3. Masajid Formation ................................ ................................ ............................... 31 4.3.3. The Creta ceous ................................ ................................ ................................ ............ 31 4.3.3.1. burg el arab formation ................................ ................................ .......................... 31 4.3.3.2. Bahariya Formation ................................ ................................ ............................. 32 4.3.3.3. Abu Roash Formation ................................ ................................ .......................... 32 4.3.3.4. Khoman Formation ................................ ................................ ............................. 32 4.3.4. The Tertiary ................................ ................................ ................................ ................ 32 4.3.4.1. Cretaceous – Paleogene (Subsurface) ................................ ................................ .... 32 4.3.4.2. Paleocene – Eocene ................................ ................................ ................................ 32 4. 3.4.3. Oligocene – Miocene ................................ ................................ ............................. 32 4.3.4.4. Neogene – Quaternary ................................ ................................ ........................... 32 4.4. ALAM EL BUIEB FORMATION ................................ ................................ .................... 33 4.4.1. AEB - 1 unit ................................ ................................ ................................ .................. 34 4 4.4.2. AEB - 2 unit ................................ ................................ ................................ ................. 34 4.4.3. AEB - 3 unit ................................ ................................ ................................ .................. 35 4.4.3.1. T he Alam El Bueib - 3 A ................................ ................................ ....................... 35 4.4.3.2. The Alam El Bueib - 3D ................................ ................................ ........................ 35 4.4.3.3 Alam El Bueib - 3E ................................ ................................ ................................ 35 4.4.4. AEB - 4 unit ................................ ................................ ................................ .................. 36 4.4.5. AEB - 5 unit ................................ ................................ ................................ .................. 36 4.4.6. A EB - 6 (Basal Unit) ................................ ................................ ................................ ..... 36 4.5. Isopach maps ................................ ................................ ................................ ...................... 37 5.PETROLEUM SYSTEM IN WESTERN DESERT ................................ ................................ 40 5.1. Source Rock Intervals in the Western Desert ................................ ................................ .... 40 5.1.1. Cenozoic Source Rocks ................................ ................................ .............................. 40 5.1.2. Cretaceous Source Rocks ................................ ................................ ............................ 40 5.1.3. Jurassic Source Rocks ................................ ................................ ................................ 42 5.1.4. Paleozoic Source Rocks ................................ ................................ .............................. 43 5.2. Reservoir Rocks ................................ ................................ ................................ ................. 44 5.2.1. Bahariya Formation ................................ ................................ ................................ .... 44 5.2.2. Alamein Formation ................................ ................................ ................................ ..... 44 5.2.3. Abu Roash G Reservoir ................................ ................................ .............................. 44 5.3. Top and Lateral Seal and Entrapment ................................ ................................ ............ 45 5.4. Trap ................................ ................................ ................................ ................................ .... 46 5.5. Migration ................................ ................................ ................................ ............................ 46 5.6. Timing ................................ ................................ ................................ ................................ 47 5 6.The petroleum plays in western desert are associated with Mesozoic formations .................... 47 6.1. Alamein Dolomite (Aptian, Lower Cretaceous) ................................ ................................ 47 6.1.1. Lithology ................................ ................................ ................................ ..................... 47 6.1.2 Source Rock ................................ ................................ ................................ ................. 47 6.1.3. Res ervoir Rock ................................ ................................ ................................ ............ 48 6.1.4. Trap ................................ ................................ ................................ ............................. 48 6.1.5. Seal ................................ ................................ ................................ .............................. 48 6.1.6. Migration ................................ ................................ ................................ ..................... 48 6.2. Bahariya Formation (Cenomanian, Upper Cretaceous) ................................ ..................... 48 6.2.1. Lithology ................................ ................................ ................................ ..................... 49 6.2.2. Source Rock ................................ ................................ ................................ ................ 49 6.2.3. Reservoir Rock ................................ ................................ ................................ ............ 49 6.2.4. Trap ................................ ................................ ................................ ............................. 49 6.2.5. Seal ................................ ................................ ................................ .............................. 49 6.2.6. Migra tion ................................ ................................ ................................ ..................... 50 6.2.7. Example Fields: ................................ ................................ ................................ .......... 50 6.3. Abu Roash "G" Member (Late Cenomanian, Upper Cretaceous) ................................ ..... 50 6.3.1. Lithology ................................ ................................ ................................ ..................... 50 6.3.2 Source Rock ................................ ................................ ................................ ................. 50 6.3.3. Reservoir Rock ................................ ................................ ................................ ............ 51 6.3.4. Trap ................................ ................................ ................................ ............................. 51 6.3.5. Seal ................................ ................................ ................................ .............................. 51 6.3.6. Migration ................................ ................................ ................................ ..................... 51 6 6.3.7. Key Fields Producing from Abu Roash G ................................ ................................ .. 51 7. Alam El - Bueib Reservoir Characterization ................................ ................................ .............. 52 7.1 Lithology & Depositional Environment ................................ ................................ ............ 53 7.1.1 LITHOSTRATIGRAPHY ................................ ................................ .......................... 53 7.1.2. METHODS ................................ ................................ ................................ ................. 54 7.1.3. Reservoir Characterization ................................ ................................ .......................... 56 7.2. Petrophysical Analysis ................................ ................................ ................................ ....... 56 7.3. Structure and Tectonic Influences ................................ ................................ ..................... 58 7.3. Hydrocarbon Potential ................................ ................................ ................................ ....... 59 7.3.1. Sampling and analytical techniques ................................ ................................ ............ 59 7.3.2. Source rock evaluation ................................ ................................ ................................ 60 7.3.2. Quantity of organic matter ................................ ................................ .......................... 60 8.Case Study of Alam El Buieb ................................ ................................ ................................ .... 60 8. 1.Geological setting ................................ ................................ ................................ .............. 61 8.2. Materials and Methods ................................ ................................ ................................ ........ 63 8.2.1.Density - Neutron and M - N Crossplots ................................ ................................ ......... 63 8.2.2.Shale volume calculation ................................ ................................ ............................. 64 8.2.3.Porosity calculation ................................ ................................ ................................ ...... 64 8.2.4. Fluid saturation ................................ ................................ ................................ ........... 66 8.3. Discrimination of reservoir lithologies ................................ ................................ .............. 66 8.3.1. AEB - 3D Reservoir ................................ ................................ ................................ ...... 67 8.3.2 AEB - 3G Reservoir ................................ ................................ ................................ ....... 69 8.3.3. AEB - 6 Reservoir ................................ ................................ ................................ ......... 72 7 8.4. Petrophysical evaluation of the Alam El - Buieb units ................................ ........................ 77 8.4.1. Litho - saturation crossplots of AEB - 3D unit ................................ ............................... 77 8.4.2.Litho - saturation crossplots of AEB - 3G Unit ................................ ............................... 82 8.4. 3.Litho - saturation crossplots of AEB - 6 unit ................................ ................................ ... 85 8.5. Conclusion ................................ ................................ ................................ ......................... 89 9. Productivity of Alam El Bueib Reservoir ................................ ................................ ................. 89 9.1. Exploration of the Western Desert ................................ ................................ ..................... 89 9.2 Introduction to the Alam - El Bueib ................................ ................................ .................... 91 9.3. Evaluation of the Shale Beds within Alam El Bueib Formation as an Unconve ntional Reservoir ................................ ................................ ................................ ................................ ... 92 9.4 Challenges and future opportunities ................................ ................................ ................... 93 9.5 Recommendations for the Enhancement of this Productivity ................................ ............. 93 9.6 Hydraulic Fracturing ................................ ................................ ................................ ........... 94 9.7. Acidization ................................ ................................ ................................ ......................... 95 9.8.Lifting the Well ................................ ................................ ................................ ................... 96 9.9 Well Stimulation Vessels ................................ ................................ ................................ .... 96 Conclusion ................................ ................................ ................................ ................................ .... 97 References ................................ ................................ ................................ ................................ ..... 98 List of Figures Figure 1. western desert petroleum system: new exploration opportunities and challenges ........ 13 Figure 2. Mesozoic - Cenozoic tectonic evolution of WD. ................................ ............................ 18 Figure 3. Mesozoic - Cenozoic deformation events of WD ................................ ........................... 19 8 Figure 4. Seismic section across the Abu Gharadig Basin, northern Western Desert .................. 23 Figure 5. Cycles of Shushan Basin. ................................ ................................ .............................. 25 Figure 6. Basins in WD ................................ ................................ ................................ ................. 26 Figure 7. Generalized litho - stratigraphic column of Western Desert, Egypt ............................... 27 Figure 8. Generalized lith o - stratigraphic column of Western Desert, Egypt. .............................. 28 Figure 9. Generalized litho - stratigraphic column of Western Desert, Egypt. .............................. 29 Figure 10. Generalized litho - stratigraphic column of Western Desert, Egypt. ............................ 29 Figure 11. stratigraphic section of the Western Desert, Egypt . ................................ ................... 30 Figure 12. Western Desert Stratigraphic Column, for Jurassic period. ................................ ........ 31 Figure 13. Western Desert Stratigraphic Column. ................................ ................................ ........ 33 Figure 14. Alam El Buieb fm. AEB - 1 to AEB - 6. ................................ ................................ ......... 34 Figure 15. triangle facies. ................................ ................................ ................................ ............. 35 Figure 16. Alam El Buieb fm. AEB - 1 to AEB - 6. ................................ ................................ ......... 36 Figure 17. Isopach maps for AEB - 1 unit and AEB - 3A. ................................ ............................... 37 Figure 18 Lithological facies For Alam El Buieb . ................................ ................................ ...... 38 Figure 19. Lithofacies types of the studied Alam El Bueib Formation in the Betty - 1 well. ........ 39 Figure 20. Rock Eval and maturity data. Above: geochemical profile on two wells (left SH18 – 1; right WNAT - 1). ................................ ................................ ................................ ............................ 41 Figure 21. Rock Eval and maturity data. Above: geochemical profile on two wells (left SH18 – 1; right WNAT - 1). Below: compilation of maturity data by source rock ................................ ......... 42 Figure 22.Rock Eval and maturity data. Above: geochemical profile on two wells (left SH18 – 1; right WNAT - 1). Below: compilation of maturity ................................ ................................ ......... 43 Figure 23. Structural cross section among Amana wells. ................................ ............................. 46 9 Figure 24 Simplified stratigraphic section of the Western Desert, Egypt. ................................ ... 53 Figure 25. Lithofacies types of the studied Alam El Bueib Formation in the Betty - 1 well. ........ 55 Figure 26. Location map of Qasr field relative to Egypt geographic map. ............................... 58 Figure 27. Western Desert basins delineation map and location of the study area. ..................... 61 Figure 2 8 . Generalized lithostratigraphic column of the Shushan basin ................................ ...... 62 Figu re 29. Density - Neutron cross - plot of AEB - 3D reservoir in the study area. .......................... 68 Figure 30. M - N cross - plot of AEB - 3D reservoir in the s tudy area ................................ .............. 69 Figure 31. Density - Neutron cross - plot of AEB - 3G reservoir in the study area. .......................... 71 Figure 32. M - N cross - plot of AEB - 3G reservoir in the study area. ................................ ............. 72 Figure 33. Density - Neutron cross - plot of AEB - 6 reservoir in the study area. ............................. 74 Figure 34. M - N cross - plot of AEB - 6 reservoir in the study area. ................................ ................ 76 Figure 35. Litho - saturation crossplots of AEB - 3D unit ................................ ................................ 78 Figure 36. Litho - Saturation Crossplot of AEB - 3D and 3G units in SHU - 1X well ...................... 80 Figure 37. Litho - Saturation Crossplot of AEB - 3D and 3G units in APRIES - 1X well. ............... 81 Figure 38. Litho - Saturation Crossplot of AEB - 3D and 3G units in GEB - 2X well ...................... 82 Figure 39. Litho - Saturation Crossplot of AEB - 3D and 3G units in SHU - 1X well ...................... 83 Figure 40. Litho - Saturation Crossplot of AEB - 3D and 3G units i n APRIES - 1X well. ............... 84 Figure 41. Litho - Saturation Crossplot of AEB - 6 unit in GEB - 1X well. ................................ ...... 85 Figure 42. Litho - Saturation Crossplot of AEB - 6 unit in GEB - 2X well . ................................ ..... 86 Figure 43. Litho - Saturation Crossplot of AEB - 6 unit in SHU - 1X well. ................................ ...... 87 Figure 44. Litho - Saturation Crossplot of AEB - 6 unit in APRIES - 1X well. ................................ 88 Figure 45. The Hydraulic Fracturing process ................................ ................................ ............... 94 10 List of T ables Table 1. Matrix densities of common lithologies constants used in the density porosity formula 65 Table 2. Petrophysical results of AEB - 3D reservoir unit in the studied wells. ............................ 67 Table 3. Petrophysical results of AEB - 3G reservoir unit in the studied wells. ............................ 70 Table 4. Petrophysical results of AEB - 6 reservoir unit in the studied wells. ............................... 73 Abstract The Alam El Bueib Formation, located in Egypt’s Western Desert, represents a significant hydrocarbon - bearing reservoir within the Lower Cretaceous succession. This study provides a comprehensive characterization of the reservoir, incorporating geological, petrophysical, and geochemical analy ses. The formation is subdivided into six units (AEB - 1 to AEB - 6), each reflecting varying depositional environments from fluvio - deltaic to shallow marine, with corresponding lithofacies including sandstones, shales, and siltstones. Structural interpretatio n highlights the role of rift and inversion tectonics in reservoir development. Petrophysical evaluation using core data and log analyses reveals variable porosity, permeability, and hydrocarbon saturation across units. Source rock assessment confirms that the Alam El Bueib, along with formations such as Khatatba and Abu Roash, contributes significantly to hydrocarbon generation, with both gas - and oil - prone kerogen types. Advanced techniques like density - neutron crossplots and litho - saturation models were used for more accurate reservoir discrimination. The reservoir's productivity is influenced by factors such as diagenesis, facies distribution, and structural traps. The study concludes with recommendations to enhance recovery through methods like hydrauli c fracturing, acidization, and well stimulation, and outlines exploration opportunities and challenges within the Western Desert basins. 11 Introduction The Alam El Bueib Formation is a significant Lower Cretaceous stratigraphic unit located in the Western De sert of Egypt, particularly within the Shushan, Abu Gharadig, and Alamein basins. It is composed primarily of interbedded sandstones, shales, and siltstones, with occasional limestone streaks. The formation is of Aptian to Barremian age and is known for it s excellent hydrocarbon potential, serving as both a reservoir and, in some cases, a source rock. The depositional environment of Alam El Bueib ranges from fluvial to shallow marine, reflecting complex sedimentary processes influenced by regional tectonics and sea - level changes. Its reservoir characteristics vary laterally and vertically, making it a key focus for exploration and development activities in the Western Desert. 1. Production History of the Western Desert The Western Desert province is one of Egypt’s most productive hydrocarbon provinces, ranking second in terms of oil production after the Gulf of Suez province and second in terms of gas and condensate production after the Nile Delta. Over the last few decades, many discoveries and t housands of wells have been drilled to explore hydrocarbons in the organic - rich sedimentary basins of the Western Desert. This chapter aims to provide comprehensive studies on the Western Desert’s total petroleum system, as well as the tectono - stratigraphi c history control on petroleum system development across the basins. The dominant source rocks, conventional reservoirs, unconventional reservoirs, seals, and petroleum traps have all been thoroughly discussed in this chapter. This chapter also includes th e major Western Desert sedimentary basins and their petroleum systems in detail. Furthermore, this chapter introduces new exploration opportunities as a means of achieving successful exploration and the discovery of new resources, such as stratigraphic tra ps, deeper targets, inversion structures and faulted traps, sequence stratigraphy application, and unconventional resources. Finally, the chapter 12 discusses the challenges that could affect hydrocarbon exploration in the Western Desert, such as drilling, pe troleum systems, and seismic imaging, as well as some mitigations. The WD is Egypt’s second most important petroliferous province in terms of oil, gas, and condensate production . Over geological time, the WD sedimentary successions formed during complex te ctonic regimes such as rifting, in version, and deformation phases ( Ra dwan, 2023). Understanding the petroleum system of hydrocarbon reservoirs in sedimentary basins is a critical factor in evaluating and simulating hydrocarbon reservoirs for better exploit ation and development. Global energy consumption has increased significantly in the last few decades as a result of significant technological advancements and rising living standards. Furthermore, a better understanding of the petroleum system elements wil l lead to more discoveries and shed light on unconventional reservoirs, which will impact countries’ economies and raise people’s living standards. Northeast Africa sedimentary basins have been distinguished by their organic richness and multi - hydrocarbon - bearing reservoirs, including the Western Desert (WD), Nile delta, Gulf of Suez and Mediterranean sedimentary basins of Egypt. Intraplate rift basins, according to Guiraud et al, are the most prolific hydrocarbon - bearing places in Northeast Africa. The Egy ptian economy is heavily reliant on petroleum energy, and governments are focusing on attracting foreign and domestic companies to invest in Egyptian petroliferous basins. Egyptian oil and natural gas production is constantly expanding as a result of ongoi ng exploration and investment activities. According to BP’s 2019 statistical report, Egyptian oil proved reserves reached 3.1 BBL in 2019, and natural gas proved reserves exceeded 75.5 TCF. The daily production of oil, natural gas, and condensate is increa sing year after year as a result of new discoveries in the three major petroleum provinces, which include WD, the Nile Delta, and the Gulf of Suez. Petroleum production sketch for Egyptian petroleum provinces, a summary of the 13 discovered volume of fluids in Egyptian petroleum main provinces, updated to 2017. Egypt’s oil production from 2009 to 2019, with proven oil reserves until 2019. Egypt’s natural gas production from 2009 to 2019, with pr oven oil reserves through 2019. BP Statisti cal Review of World En ergy 2020 ( Radwan , 2023). Figure 1. western desert petroleum system: new exploration opportunities and challenges (Dolson, 2020) 14 Petroleum production sketch for Egyptian petroleum provinces, a summary of the discovered volume of fluids in Egyptian petroleum main provinces, updated to 2017, b Egypt’s oil production from 2009 to 2019, with proven oil reserves until 2019; c Egypt’s natural gas production from 2009 to 2019, with pr oven oil reserves through 2019. BP Statisti cal Review of World Energy 2020 (Dolson, 2020) 1.1. T he Western Desert’s Major Province The WD is Egypt’s second most important petroliferous province in terms of oil, gas, and condensate production . Over geological time, the WD sedimentary successions formed during complex tectonic regimes such as rifting, inversion, and deformation phases. The WD sedimentary succession is rich in reservoir intervals and organic - rich source rocks. Rifting in WD begi ns in the Late Triassic, but the main rifting phase is mostly associated with the Middle Jurassic. These basins are formed by a southwestward thickening Paleozoic strata overlying the crystalline basement complex, which is followed by a northward thickenin g Mesozoic - Neogene sedimentary pile. The north WD rift basins were formed during the Early Mesozoic continental breakup phase, following the opening of the Neo - Tethys Ocean. Throughout the Mesozoic, the WD coastal rift basins remained a br oad shelf region near sea level ( Katz, 1995 ). They witnessed various transitions between continental and marine deposition, so facies changes are regular. The North WD of Egypt (greater Western Desert basins) is a crucial component of Northern Africa’s unstable she lf. The North WD of Egypt has been subjected to various tectonic regimes since the Paleozoic Era, allowing the formation of multiple basins, sub - basins, ridges, platforms, and troughs. Most significant hydrocarbon accumulations have been encountered in Mes ozoic rift basins of the WD. More than 3 (bnboe) were produced from the WD’s overall reservoirs, with the Cretaceous and Jurassic reservoirs contributing significantly 15 (IHS and WoodMac, online source). According to Dolson, the estimated reserves of the WD as high as 5.6 billion barrels of oil equivalent (BBOE) recoverable to date, with additional reserves yet to be discov ered that could reach 7 BBOE ( Garfunkel, 2004 ). 1. 2 General Lithostratigraphy of the Western Desert The WD lithostratigraphy contains a variety of lithologies ranging from the Cambrian to more recent deposits that have been influenced by numerous tectonic events which have formed its current sedimentary succession. The WD’s sedimentary succession was influenced by transgressive/regressive cycles that constrained its evolution. The Paleozoic succession in WD is characterized by coarse and fine clastics, as well as minor carbonate rocks that overlie the basement rocks. Four major regressive cycles distinguished the WD sedimentary succession, each terminated by a marine transgression . The Middle to Late Jurassic non - marine clastics (Ras Qattara formation) represent the earliest cycle, and the deposition continued by the marine deposits of the Khatatba formation. The earliest cycle was ended by the maximum transgression surface represented by the Late Callovian carbonates of the Masajid formation. The post - Paleozoic sedimentary succession consists of alternating clastic and carbonate strata from four major depositional cycles: The Jurassic, Lower Cretaceous, Upper Cretaceous, and Paleogene. The syn - rift sediments originate from the Jurassic and Lower Cretaceous cycles, whereas the post - rift strata belong to the Upper Cretaceous and Paleogene. The syn - rift sediments originate from the Jurassic and Lower Cretaceous cycles, whereas the post - rift strata belong to the Upper Cretaceous and Paleogene. The Lower Jurassic fluvio - lacustrine siliciclastics of the Yakout and Ras Qattara formations overlie the Paleozoic sandstones unconformably in the Jurassic cycle. The Middle Jurassic sediments comprise the Khatatba formation’s coastal and shallow marine 16 strata, which are followed by the Masajid formation’s marine carbonate that represents the maximum extent of t he Jurassic transgressive phase (Said, 1990; Sul tan & Halim, 1988) 2. Tectonics and Structural Features of The Western Desert 2 .1 . Early Mesozoic Tethyan Rifting The Tethyan rifting impacted Egypt's northern onshore and offshore areas, creating NE to ENE oriented basins and sub - basins. Normal fault s with the same orientation can be found throughout central and southern Egypt. The Afro - Arabian and Eurasian plates diverged, causing Tethyan rifting. Detailed subsurface mapping of the northern Western Desert using 3D seismic and borehole data identifi ed many Tethyan extensional basins, including Kattaniya, Mubarak, Alamein - Razzak, Matruh, and Shoushan. The Faghur Basin is considered part of the Shoushan Basin (Bosworth et al. 2015) 2 .2. Cretaceous Rifting Subsurface mapping for hydrocarbon exploration led to the recognition of several Cretaceous rift basins in the northern Western Desert. These basins have Cretaceous syn - rift rock thickening along NW - SE to WNW - ESE oriented normal faults. The fault blocks in these half - graben basins are tilte d and dip toward the northeast. (For example, Abu Gharadig) (Moustafa et al., 2003). 2.3. Late Cretaceous to Recent TethyanConvergence During the Late Cretaceous - Recent period, the African and Eurasian Plates converged, resulting in compressional structur es. The oldest evidence of convergence can be seen in the Late Cretaceous and Early Tertiary folds impacting Mesozoic exposures in northern Egypt, which are already part of Krenkel's (1925) Syrian Arc System. Geologists have long been drawn to the folds o f Abu Roash and the Bahariya Oases in the Western Desert. Hydrocarbon drilling in the northern 17 Western Desert revealed comparable folding patterns in Mesozoic and earlier strata. Northern Egypt's surface and subsurface folds align NE - SW and are linked to various fault types and orientations. Folding began in the Late Cretaceous, during the Santonian - Campanian period, and reached its peak magnitude. However, it persisted slightly until the Tertiary. Younger convergence structures are more visible in the n orthernmost sections, indicating deformation. Younger convergence structures are more visible in the northernmost sections, indicating that deformation began in the south and spread to the northernmost part of the plate. The Late Cretaceous - Tertiary conve rgent structures were reactivated (inverted) from Jurassic rift structures, which were the first to respond to compressive stress caused by plate convergence. After a long period of reactivation, compressive stress created new structures in the northern s ection of the plate. Northern Egypt's Jurassic rift basins were influenced by Late Cretaceous - Tertiary inversion. Inversion folds are NE - SW oriented and span several tens of kilometers in length and around 20 km in width. The flanks of the inverted main basin - bounding faults are steep, vertical, or overturned, making them asymmetric. Inversion structures are visible in the following regions. Western Desert (Abu Roash area and Bahariya Oases) Inversion structures were also recognized in the subsurface (du ring exploration for hydrocarbons) in the following areas :Northern Western Desert (Kattaniya, Alamein - Razzak,Mubarak, Abu Gharadig, and Matruh - Shoushan Basins). It is obvious that the inverted main basin - bounding faultschange polarity from northern Sinai to the northern WesternDesert For this reason, the steep flanks of theinversion folds also follow this polarity change. (Abdel Aal et al., 2000). 18 Figure 2. Mesozoic - Cenozoic tectonic evolution of WD. Cartoons showing relative plate movements are shown below each map (moustafa,2020). 19 Figure 3. Mesozoic - Cenozoic deformation events of WD After ( Moussa , 1987) 20 2 .4 Structural Features of the Western Desert Most of the basins in the are a was opened during jurasic due to extention forces then during late cretaceous these basins is inverted making wonderful structures like 2.4.1. The Kattaniya inverted basin The Kattaniya inverted basin is approximately 120 km long and 40 km wide, extendi ng east of the Nile River. According to Abd El - Aziz et al. (1998), the Kattaniya Basin's syn - rift rocks contain Jurassic sediments from the basin's depocenter at a depth of 2750 meters. Basin inversion during the Late Cretaceous Period.During the early Ter tiary period, a wide NE - SW oriented asymmetric anticline with considerable structural relief emerged, similar to the Gebel Maghara area During the Campanian - Maastrichtian, Paleocene, and Eocene periods, the crest of the anticline eroded deeply, exposing Lo wer Cretaceous rocks that were later covered by Oligocene shales from the Dabaa Formation. The Campanian - Maastrichtian Khoman Chalk and Paleocene - Middle Eocene Apollonia Formation were not deposited above the crest of the anticline that formed an island in the Late Cretaceous - Middle Eocene seas. (Salem , 1976) 2.4.2. Mubarak Inverted Basin Mubarak inverted basin lies at a short distance to thesouth west of the Kattaniya Basin. It has NE - SW orientationand the main inversion anticline is located at the northwestern side of the basin The magnitudeof inversion is less than that of the Kattaniya Basin as normal fault separation is obvious at the lower part of theinverted main basin - bounding fault. The southeasternbounding fault of Mubarak Basin was also inv erted forminga small - relief anticline at this side of the basin Syn - rift sediments in the Mubarak Basin are represented by