1 Introduction

The exploration and production of hydrocarbon reservoirs remain at the forefront of the global energy industry, as these resources continue to be pivotal for meeting the world's ever-growing energy demands. In the quest to maximize the extraction of hydrocarbons, the identification of subsurface traps—geological structures that can entrap oil and gas—plays a paramount role (Imam et al. 2022; Reda et al. 2022; Shehata et al. 2023a; Abdel-Fattah et al. 2023a; Mamdouh et al. 2023). Understanding the intricacies of these traps is a complex endeavor, often requiring a multi-disciplinary approach that amalgamates various geological, geophysical, and petrophysical data sources (Fadul et al. 2020; Abdel-Fattah et al. 2020, 2023b; Gawad et al. 2021b; Abdelwahhab 2022; Shehata et al. 2023b).

The importance of integrating seismic, well log, and fault seal analysis for hydrocarbon trap identification cannot be overstated. It represents a paradigm shift in the way we understand subsurface geology and reservoir behavior (Abdel-Fattah et al. 2021; Gawad et al. 2021a, 2021b). This multidimensional approach offers a holistic view of the subsurface, allowing for more accurate predictions and informed decision-making at all stages of the oil and gas exploration and production process. Seismic data provides a comprehensive view of subsurface structures through the use of sound waves that bounce off rock layers. It offers a glimpse into the geometry of geological features, such as faults, folds, and stratigraphic variations. When integrated with well log and fault seal data, seismic data can reveal the three-dimensional geometry of potential traps, improving the precision of reservoir delineation and reducing exploration risks. Well log data is acquired by measuring the properties of the rock and fluid within a borehole, providing detailed information about lithology, porosity, permeability, and hydrocarbon content (Mahdi et al. 2022; Reda et al. 2022; Mamdouh et al. 2023). By merging well log data with seismic information, it can better understand the reservoir's petrophysical properties, aiding in the estimation of hydrocarbon volumes and the identification of potential sealing and trapping mechanisms. Fault seal analysis examines the sealing capacity of fault zones by considering factors such as fault geometry, rock properties, and the presence of clay gouges (Abdel-Fattah et al. 2021). When combined with seismic and well log data, fault seal analysis helps identify potential sealing mechanisms, enhancing our ability to locate hydrocarbon traps effectively. The integration of these three data sets not only improves our understanding of hydrocarbon trap formation but also plays a pivotal role in optimizing drilling strategies, reservoir management, and production techniques. As the industry faces increasing challenges, including the exploration of unconventional resources and the need for enhanced oil recovery from mature fields, the synergy of seismic, well log, and fault seal analysis becomes even more critical.

The study area in the Egyptian Western Desert, particularly the Meleiha concession (Fig. 1), is known for its rich hydrocarbon deposits (Klitzsch et al. 1979). A comprehensive analysis of the region, spanning 300 km2 and involving 2D and 3D seismic surveys, reveals the complexity of sedimentary attributes, including heterogeneity (Abdelwahhab et al. 2021; Radwan et al. 2021; Shehata et al. 2021; Reda et al. 2022; Mamdouh et al. 2023). Geological studies, such as those by Sultan and Abd El Halim (1988), Abd Elhady et al. (2015), and Abdel-Fattah et al. (2017), underscore the presence of Paleozoic deposits with favorable reservoir characteristics. The study primarily focuses on late Cretaceous strata, specifically the Bahariya Formation, to gain insights into the underlying Alamein Dolomite Formation and AEB Member discovered in 1998. This research significantly contributes to advancing our understanding of hydrocarbon traps in the region.

Fig. 1
figure 1

The base map for the study area, showing the Meleiha Development Lease on the Egypt map and the selected seismic sections in the southern part of Meleiha

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The primary objective of this study was to thoroughly investigate the integration of seismic, well log, and fault seal analysis for the identification of hydrocarbon traps. It aimed to delve into the practical aspects of this approach, exploring methodologies, tools, and case studies with the potential to revolutionize the efficiency and sustainability of the oil and gas industry in meeting global energy demands. Specifically, the study focused on the southern Meleiha concession, which falls within the development encouragement areas managed by the Agiba Petroleum Company in between Matrouh basin and Shushan basin, covering an approximate area of 700 km2. The core aim was to enhance our understanding of trap identification within the late Cretaceous strata encompassing the Bahariya, Alamein Dolomite, and Alam El Bueib Members.

2 Regional geology

The North Western Desert is characterized by a series of basins oriented in an east–west and northeast-southwest direction, forming a graben system. These basins were formed along pre-existing structural features in the underlying basement rock as a result of the Tethyan rifting process, which involved the separation of the African and European continents (Schandelmeier et al. 1987; El Ayouty 1990; Meshref 1990; Abdel-Fattah et al. 2015; Salman 2021). This geological phenomenon occurred during the Middle Jurassic to Lower Cretaceous epochs, primarily focusing on the northern boundary of the arid region. The sedimentary layers in the North Western Desert exhibit a distinct pattern of increasing thickness. Paleozoic sediments tend to thicken in the southwestern direction, while Mesozoic and Tertiary sediments increase in thickness in the northern direction. This pattern is disrupted by the presence of the east–west-oriented Hercynian Orogeny Sharib-Sheiba high. These insights are drawn from the research conducted by Zein El-Din et al. (2001).

The North Western Desert is particularly noteworthy for its basins with significant accumulations of Mesozoic sedimentary deposits. Scholars have shown keen interest in the stratigraphy of these basins, as indicated by the works of Rossi et al. (2001), Catuneanu et al. (2006), and Mahmoud et al. (2017, 2019), El-Younsy and Salman, (2021), Reda et al. (2022), Mamdouh et al. (2023), Salman (2023). The geological sequence in the North Western Desert, particularly in the Shushan Basin, spans from the Paleozoic era to the Tertiary era (Fig. 2).

Fig. 2
figure 2

Generalized stratigraphic column of the Western Desert, after (Schlumberger 1984)

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The composition of this geological formation exhibits a distinct pattern of clastic and carbonate phases, as observed by El Diasty et al. (2016). The study site is situated in a desert environment dominated by Tertiary sedimentary formations, ranging from the Miocene to Oligocene epochs. The topography primarily consists of level to gently inclined gravel plains, with a limited number of low-lying sand dunes aligned in a northwest to southeast direction, originating from the Plio-Pleistocene epoch. The sedimentary deposits in the northern Western Desert predominantly consist of alternating strata of sandstone and shale, with limited occurrences of limestone formations, as described by Hanter (1990). The Paleozoic sediments in the research area are found in the transitional zone connecting the Kattaniya High and the Gindi Basin, encompassing a narrow continental sandstone stratum of Permo-Jurassic origin known as Ras Qattara. This layer has been identified in several wells within the Falak field, according to Abd El-Aziz et al. (1998).

The Mesozoic strata in the region can be classified into three distinct sedimentary cycles, each comprising a lower unit characterized by sandy sediment deposited under alluvial plain conditions, followed by sequences of transgressions marked by shallow, marginal marine deposits (Klitzsch et al. 1979). These transgressions were observed during the Late Jurassic, Middle Cretaceous, and Late Cretaceous epochs, potentially corresponding to global fluctuations in sea levels. Schlumberger (1984) notes that the Maastrichtian transgression extended southward beyond the 24′ N latitude. The Mesozoic and Cenozoic portions of the northern Western Desert have been categorized into four cycles, each culminating in a marine transgression, with initial systematic categorization by Norton (1967). The Jurassic formations along the coast are divided into units such as the Wadi El Natrun, Khatatba, and Masajid Formations based on vertical locations, while continental formations from the Permo-Triassic to Jurassic epochs are classified as the Eghei Group.

The tectonic history of northeastern Africa has been extensively documented, with plate movements contributing to the structural evolution of the region. Continental plate collisions, interrupted by phases of extension and rifting, have played a crucial role in shaping the tectonic characteristics of northeastern Africa (Sengor and Gorür 1985). The rotation of the African plate relative to Eurasia has also had a significant impact on the region’s structural development, leading to the formation of secondary structures within right-lateral wrench zones, as proposed by Bayoumi (1996).

The authors of this study conducted a detailed investigation into the rock formations of the Mesozoic and Cenozoic periods in the northern Western Desert of Egypt. They also analyzed changes in geological structures and basin arrangements in this region. Their research identified three main tectonic deformations in Northern Egypt, which encompassed phases of Jurassic/Early Cretaceous Rifting, Late Cretaceous–Early Tertiary Wrenching, and Miocene and Post-Miocene Extension (Moustafa et al. 1998).

3 Oil field background

The Meleiha development lease comprises several subordinate areas that are currently involved in or have previously been involved in the extraction of oil and gas resources. The primary reservoirs for these fields are the Alam El-Bueib Formation of the Lower Cretaceous and the Khatatba Formation of the Jurassic period. Within the southern region of Meleiha, there are multiple regions of interest, each housing distinct fields with unique hydrocarbon production characteristics, as illustrated in Fig. 3. These fields include Bardy, Bardy West, Bardy Deep, Banafsag, Banafsag Deep, Gawaher, Gawaher North, Gawaher North West, Sanapl, Salma, Zahra, Zahra East, Zahra East Deep, Zahra North East, Zahra North, East Salam, and Clove Shallow. Table 1 provides a comprehensive analysis of the net pay within this designated area, offering insights into the number of active and non-producing wells in the region (Agiba, 2019). Covering a total area of approximately 300 km2, these 17 fields consist of a significant number of both shallow and deep wells.

Fig. 3
figure 3

South Meleiha area location map containing key field wells, modified after (Agiba Geological Team 2010)

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Table 1 Calculated net pay thickness in the southern Meliha concession, Abu El-Gharadig basin, Egypt
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The shallow wells primarily target reservoirs composed of sandstone within the Bahariya Formation. However, the productivity of these wells is limited due to the reservoir’s quality and the high gravity of the oil (Agiba 2019). The Meleiha development lease encompasses various geological structures, including Dorra, Meleiha Deep, Falak, Nada, Meleiha Deep SW, N Nada, Bostan, Jasmin, Emry Deep, Rosa, and Arcadia. These structures have provided evidence of the presence of oil and gas reserves within the Alam El-Bueib Members (Agiba 2005).

4 Materials and methods

To achieve our research objective of integrating seismic, well log, and fault seal analysis for a comprehensive understanding of the South Meleiha region in the Western Desert of Egypt, we gathered critical data from two primary sources: digital well-log data and two-dimensional seismic data. Our study extensively relied on digital well-logs stored in the form of Las files as well as printed composite log forms. These data were meticulously obtained from five strategically chosen wells within the study region. The specific well names are Zahra_1X, Zahra_E_D_1X, Bardy_W_1X, Sanapl_1x, and Bardy_D_1X_ST. It is imperative to underscore that all the data presented in this report was acquired through proper authorization from the relevant Egyptian authorities. Our seismic dataset predominantly consisted of north–south oriented dip seismic lines, with a subset intersecting five of the aforementioned wells, as visually represented in Fig. 1. Additionally, we incorporated several east–west oriented strike lines into our dataset. The cumulative length of the in-line seismic sections was approximately estimated at 26 km, while the cross-line sections spanned approximately 11.5 km, effectively covering an extensive area of roughly 300 square kilometers. To ensure the highest precision and reliability, we adhered rigorously to the interpretation methodology elucidated in Fig. 4.

Fig. 4
figure 4

Generalized flowchart of seismic data loading, velocity analysis, and well log interpretation

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The initial stage of integrating seismic, well log, and fault seal analysis for hydrocarbon identification begins with the acquisition and preparation of essential data. Well logs, which provide crucial insights into subsurface rock properties, are obtained through the drilling of strategically located boreholes. These logs encompass a range of data, including gamma-ray, resistivity, neutron porosity, and sonic measurements. Each of these measurements offers unique information about the lithology, porosity, permeability, and hydrocarbon content of the geological formations. The well well-logged is then digitized and organized for further analysis. Well log data plays a critical role in understanding petrophysical properties within these traps, including porosity and permeability, which are essential for estimating hydrocarbon volumes. The assessment also considers parameters such as effective porosity, hydrocarbon saturation, and net pay thickness.

The M–N cross-plot method offers a valuable tool for mineral identification, enabling the determination of lithological composition at various levels, as documented by Schlumberger (1973). The effectiveness of this approach hinges on incorporating fluid and log characteristics from three porosity logs: the sonic, density, and neutron logs. The combination of these variables significantly improves the ability to distinguish lithological attributes, as emphasized by Pirson (1963). For clarity, definitions for the letters M and N, as outlined by Burke et al. (1968), are provided.

$${\text{M}} = \left[ {{{\left( {\Delta_{{{\text{tf}}}} {-}\Delta {\text{t}}_{{{\text{log}}}} } \right)} \mathord{\left/ {\vphantom {{\left( {\Delta_{{{\text{tf}}}} {-}\Delta {\text{t}}_{{{\text{log}}}} } \right)} {\left( {\uprho _{{\text{b}}} {-}\uprho _{{\text{f}}} } \right)}}} \right. \kern-0pt} {\left( {\uprho _{{\text{b}}} {-}\uprho _{{\text{f}}} } \right)}}} \right]*0.0{1}$$
(1)
$${\text{N}} = {{\left( {\emptyset_{{{\text{Nf}}}} {-}\emptyset_{{\text{N}}} \log } \right)} \mathord{\left/ {\vphantom {{\left( {\emptyset_{{{\text{Nf}}}} {-}\emptyset_{{\text{N}}} \log } \right)} {\left( {\uprho _{{\text{b}}} {-}\uprho _{{\text{f}}} } \right)}}} \right. \kern-0pt} {\left( {\uprho _{{\text{b}}} {-}\uprho _{{\text{f}}} } \right)}}$$
(2)

Calculating shale volume using the linear technique is based on the methodology introduced by Schlumberger in 1972. The estimation of shale volume (Vsh) can be accomplished by employing density and neutron logs, following the equation proposed by Dresser in 1979.

$$\left( {{\text{V}}_{{{\text{sh}}}} } \right){\text{D}} - {\text{N}} = \left[ {{\text{A}}/{\text{B}}} \right]$$
(3)
$${\text{A}} = \left[ {{\text{ p}}_{{{\text{blog}}}} \left( {\Delta {\text{N}}_{{{\text{mat}}}} {-}1.0} \right){-}\Delta {\text{N}}_{\log } \left( {{\text{p}}_{{{\text{mat}}}} {-}{\text{p}}_{{\text{f}}} } \right){-}{\text{p}}_{{\text{f}}} \left( {\Delta {\text{N}}_{{{\text{mat}}}} + {\text{p}}_{{{\text{mat}}}} } \right)} \right]$$
(4)
$${\text{B}} = \left[ {\left( {{\text{p}}_{{{\text{sh}}}} {-}{\text{p}}_{{\text{f}}} } \right)\left( {\Delta {\text{N}}_{{{\text{mat}}}} {-}1.0} \right){-}\left( {{\text{Nsh}}{-}1.0} \right)\left( {{\text{p}}_{{{\text{mat}}}} {-}{\text{p}}_{{\text{f}}} } \right)} \right]$$
(5)

Simultaneously, seismic data is gathered through 2D or 3D surveys employing sound waves to image subsurface structures. This method reveals the geometry of geological features like faults, folds, and stratigraphic variations. The collected seismic data is subjected to preprocessing, which involves noise reduction, amplitude correction, and the creation of seismic attribute maps. In parallel, fault seal analysis data is compiled, focusing on the sealing capacity of fault zones. Parameters such as fault geometry, rock properties, and the presence of clay gouge are evaluated to understand how these features might influence hydrocarbon migration.

The second phase involves the integration and interpretation of the collected data. The well log data is correlated with the seismic information, creating a comprehensive understanding of the subsurface. This correlation allows for the identification of seismic horizons that correspond to geological properties observed in well logs. For example, the identification of sandstone layers in well logs can be matched with seismic reflections, aiding in the delineation of potential reservoirs.

Concurrently, fault seal analysis is performed to assess the sealing capacity of fault zones. By considering factors such as fault geometry and rock properties, the analysis helps identify potential sealing mechanisms that may trap hydrocarbons. This integrated approach offers a holistic view of the subsurface, allowing for more precise predictions and informed decision-making at all stages of the exploration and production process.

The final step of the workflow centers on hydrocarbon identification and assessment. The integrated insights from seismic, well log, and fault seal analysis are used to pinpoint potential hydrocarbon traps. Structural traps, formed by subsurface deformation, and stratigraphic traps, arising from changes in rock properties, are identified based on the integrated data. Depth mapping and three-dimensional modeling are employed to create accurate subsurface representations, allowing for the quantification of hydrocarbon reserves.

This systematic workflow, encompassing detailed data collection, integration, and interpretation, ensures a comprehensive understanding of subsurface conditions. It enables effective identification and assessment of hydrocarbon reserves, critical for the success of oil and gas exploration and production endeavors.

5 Results

5.1 Well-log analysis

In the results of the wire-line well evaluation, which represents a dependable and readily accessible geophysical-geological approach for hydrocarbon exploration and extraction, the well-log analysis focused on investigating wire-line measurements and processes applicable to these endeavors.

The examination of well-logged data, obtained through various logging techniques such as gamma ray log, resistivity log, density log, neutron log, sonic log, and others, centered on the Bahariya Formation, Alam El Bueib Member, and Khatatba Formations. The primary objective was to determine critical parameters related to clay and silt content, effective porosity, water, and hydrocarbon saturation. This analysis also provided a detailed description of lithofacies within these formations, highlighting distinctive features like the presence of sandstone with calcareous facies.

Figure 4 illustrates the workflow for reservoir appraisal utilizing CPI. Formation temperature (FT) estimation played a crucial role in geological formation evaluation, given the variation in bottom hole temperature (BHT) between 185°F and 282°F. Temperature fluctuations significantly impacted the resistivity of drilling mud (Rm), mud filtrate (Rmf), and formation water (Rw), leading to substantial resistivity variations. To establish cutoff values for the Bahariya Formation’s shallow target in the study area, specific criteria were applied, including an effective porosity of 12%, shale volume of 35%, and water saturation of 65%. Table 2 provides summarized cutoff parameters for the Bahariya, Alam El-Bueib, and Khatatba-Ras Qattara formations, while Table 3 presents findings from the petrophysical parameters of these formations following the application of cutoff values.

Table 2 Summarized cutoffs parameters for Bahariya, Alam El-Bueib Members and Khatatba – Ras Qattara formations
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Table 3 Summarized resulted petrophysical parameters for Bahariya Formation, Alam El Bueib Members and Khatatba–Ras Qattara formations
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5.1.1 M–N cross-plot (tri-porosity)

The creation of the M–N cross-plot aimed to visually represent the distribution of plotted points exclusively within the pure minerals and rocks in two specific wells, specifically Bardy_Deep_1X_ST and Zahra_1X. The selection of these wells was based on the availability of sonic logs. Consequently, M–N cross-plots for the Bahariya Formation, Alam El-Bueib Members, Khatatba, and Ras Qattara formations are not accessible for other wells in the surrounding areas.

The M–N cross-plot for the Zahra_1X well provides insights into the Bahariya Formation, Alam El-Bueib Member, and Khatatba Formation, as illustrated in Fig. 5. Examination of the M–N (tri-porosity) cross-plot reveals that the predominant lithology in the BARDY-D-1X-ST well within the Bahariya Formation is sandstone. This sandstone primarily consists of quartz minerals and features calcareous cement, contributing to secondary porosity across all Alam El-Bueib Members. Notably, the presence of gases is observable within the sandstone formations of the Alam El-Bueib Members, in the BARDY-D-1X-ST well and Khatatba Formation. In the Zahra 1X Well, the predominant mineralogical composition observed in the Bahariya Formation and Alam El-Bueib Member is also sandstone with calcareous cement, closely associated with secondary porosity and some gases. This composition bears similarities to the ideal gases and secondary porosity noted in the Khatatba and Rad Qattara Formations.

Fig. 5
figure 5

M–N cross plot of Bahariya Formation, Alam El Bueib Members, and Khatatba Formation for Zahra_1X Well

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5.1.2 Dia-porosity cross-plots

Dia-porosity cross-plots are generated by integrating two types of porosity logs, specifically neutron, density, and sonic logs. Figure 6 illustrates a neutron-density cross-plot that has been constructed to effectively differentiate between sandstone, limestone, dolomite, and shale within the Bahariya Formation, Alam El-Bueib Members, and Khatatba-Ras Qattara Formation. This cross-plot offers a high level of precision in identifying and distinguishing these various lithologies within the analyzed rock units of reservoir formations.

Fig. 6
figure 6

Neutron-density cross plot for different formations of Bardy_Deep_1X_ST Well

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Analysis of the neutron-density cross-plots suggests that the predominant lithology in the Bardy_Deep_1X_ST well within the Bahariya, Khatatba, and Ras Qattara formations is calcareous sandstone, while in the Alam El-Bueib Member, it is pure sandstone. In the Zahra-E-D-1X well, calcareous sandstone is identified in the Bahariya formation, exhibiting notably high porosity. A similar porosity profile is observed in the sandstone of the Alam El-Bueib Member, while the deep target area is characterized by pure sandstone. Additionally, it’s noteworthy that calcareous sandstone is present in the Zahra-1X well within the Bahariya formation and Alam El-Bueib Member, but in the Khatatba-Ras Qattara Formation, it is recognized as clean sandstone.

The application of this technology was limited to the Bardy_Deep_1X_ST and Zahra_1X wells due to the exclusive recording of the acoustic log at these locations. The use of a neutron-sonic cross-plot technique provides a high degree of accuracy in distinguishing between sandstone, limestone, and dolomite, in addition to the already identified shale, within the examined rock formations of reservoirs. Figure 7 below illustrates the neutron-sonic cross-plots of the Bahariya Formation, AEB Member, and Khatatba-Ras Qattara Formation in the investigated area. These cross-plots reveal that the primary constituent of the Bahariya formation in the Bardy_Deep_1X_ST and Zahra_1X wells is predominantly sandstone and calcareous sandstone. Occasionally, a small proportion of limestone and dolomite is present, corresponding to the calcareous cement within the formation. The predominant lithology in the two wells under examination for the AEB Mbr is sandstone, with minimal occurrences of limestone. The Khatatba and Ras Qattara formations are primarily composed of sandstone.

Fig. 7
figure 7

Neutron-sonic cross plot of the Bahariya Formation, Alam El Bueib Members, and Khatatba Formation for Zahra_1X Well

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5.1.3 Determination of shale volume (Vsh)

The determination of shale volume (Vsh) plays a pivotal role in distinguishing between reservoir rocks and non-reservoir rocks. Assessing shale formations presents a multifaceted challenge due to the diverse impacts different logging tools experience in the presence of shale. Shale indicators are categorized based on the number of logs used, namely as single-curve and double-curve shale indicators (Poupon et al. 1970; Schlumberger 1972; Atlas 1979). The gamma-ray method proves highly effective in shale diagnosis when radioactivity originates exclusively from shale and the shale’s radioactive content within the formation remains consistent.

Shale volume in the examined area of the Bahariya Formation was determined using both single- and double-clay indicators. The first dataset, Zahra_1X, reveals a shale proportion of 21%. The second dataset, Zahra_E_D_1X, demonstrates a shale proportion of 32%. Lastly, the third dataset, Sanapl_1X, displays a shale proportion of 10%. Table 3 provides a comprehensive summary of the petrophysical characteristics obtained for the Bahariya Formation, Alam El Bueib members, and Khatatba Formation.

In both wells Zahra_1X and Zahra_E_D_1X, the shale volume within the Alam El-Bueib components, excluding Haigh, is observed to be 10%. The shale volume in Zahra_E_D_1X is relatively low, accounting for approximately 15% in the Khatatba and Ras Qattara formations. Conversely, the other two wells exhibit negligible shale volume, with Bardy_D_1X_ST and Zahra_1X wells having a shale volume of only 1%. Figure 8 displays iso-shale volume contour maps, illustrating the distribution of shale volume within the Bahariya formation, Alam El-Bueib components, and Khatatba formations in the studied area.

Fig. 8
figure 8

Shale volume distribution map for different formations (Bahariya Formation, Alam El Bueib Members, and Khatatba Formation)

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5.1.4 Determination of formation porosity (Ф)

Porosity can be determined by utilizing measurements of sonic velocity, density, neutron logs, or a combination of these log types in both clean and shaly zones. The actual porosity of the geological formation can be determined by employing a combination of density and neutron log data, as facilitated by the mathematical equation proposed by Poupon et al. (1970). In cases where gas is present in the rock pores, the formula (Schlumberger 1989) can be applied to ascertain that DC exceeds NC in magnitude.

The effective porosity (Фeff) values of the Bahariya Formation in the wells assessed within the analyzed region exhibited a range of 15–20%. Notably, the effective porosity of AEB members experienced a 5% increase, spanning from the Zahra-1X well in the western region to the Bardy_D_1X_ST well in the eastern region. As one moves eastward from the Zahra_E_D_1X well, the effective porosity of the Khatatba Formation increases to 13% at the Bardy_D_1X_ST well. Conversely, when moving westwards, towards the Zahra_1X well, it reaches 15%. The effective porosity also exhibits an increase in a north-to-east direction at Bahariya and Alam El-Bueib. Figure 9 illustrates an iso-porosity contour map that depicts the spatial distribution of effective porosity within the Bahariya, Alam El-Bueib Member, and Khatatba formations.

Fig. 9
figure 9

Iso-porosity contour map for the Bahariya Formation, Alam El Bueib Members, and Khatatba Formation

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5.1.5 Determination of the formation’s water resistivity (Rw)

The determination of reservoir water resistivity (Rw) holds paramount importance as it plays a pivotal role in the interpretation process, particularly in calculating the saturation of either water or hydrocarbons based on resistivity logs. The calculation of Rw was carried out utilizing the Pickett plot method, as outlined by Pickett in 1966. The Pickett plots for the Bardy_D_1X_ST dataset was generated following the methodology depicted in Fig. 10. To ascertain water resistivity (Rw) using Archie’s equation, a logarithmic scale is applied to graph the deep resistivity against porosity. This plotting approach results in a linear distribution of the data, in accordance with the equation proposed by Pickett in 1966.

$${\text{Y}} = {\text{mX}} + {\text{b}}$$
(6)
$${\text{Log}}\left( \Phi \right) = - 1/{\text{m}}\;\log \left( {{\text{R}}_{{\text{t}}} } \right){-}{\text{n}}\;{\text{Log}}\left( {{\text{S}}_{{\text{w}}} } \right) + {\text{Log}}\left( {{\text{a}}.{\text{R}}_{{\text{w}}} } \right)$$
(7)
Fig. 10
figure 10

Pickett plot of Bahariya Formation, Alam El Bueib Members, and Khatatba Formation for Bardy_Deep_1X_ST. A The selected water zone in Bahariya FM. B All well. C The selected sand-water zone on the log

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Water resistivity values for the Bahariya Formation were determined as follows: Bardy_D_1X_ST, Zahra_1X, Zahra_E_D_1X, and Bardy_W_1X wells exhibited values of 0.033 Ohm m, while the Sanapl_1X well recorded a value of 0.05 Ohm m. In the Alam El-Bueib components, the electrical resistivity values were found to be 0.017 Ohm m for Bardy_D_1X_ST, 0.016 Ohm m for Zahra_1X, and 0.012 Ohm m for Zahra_E_D_1X. As for the Khatatba and Ras Qattara formations, the water resistivity was noted at 0.02 Ohm m in both the Bardy_D_1X_ST and Zahra_E_D_1X wells. For a concise summary of cutoff parameters for the Bahariya, Alam El-Bueib members, Khatatba, and Khatatba-Ras Qattara formations, please refer to Table 2.

5.1.6 Determination of fluid saturations

In clean or non-shaly formations characterized by uniform intergranular porosity, the determination of water saturation (Sw) in reservoirs inside the uninvaded zone is often accomplished using the Archie (1942) equation. The water saturation of the Bahariya Formation in the examined area exhibits variability across different regions due to the significant spatial separation between the fields.

Specifically, the percentage values for different formations in the Bahariya region are as follows: Zahra_1X displays a range of 52%, which increases to 61% in Zahra_E_D_1X. Sanapl_1X demonstrates a percentage of 86%, while Bardy_W_1X exhibits 92%. The highest observed percentage is 98% in Bardy_D_1X_ST. In contrast, the water saturation levels in the Alam El-Bueib members of the Bardy_D_1X_ST well are recorded at 10%, while Zahra_1X shows 89%, and Zahra_E_D_1X records 93%. Moving on to the Khatatba and Ras Qattara formations, Bardy_D_1X_ST exhibits a water saturation of 95%, Zahra_E_D_1X has a water saturation of 68%, and Zahra_1X has a water saturation of 51%. A summarized presentation of this data is available in Table 3, and a visual representation is provided in the iso-water saturation contour map (Fig. 11).

Fig. 11
figure 11

Iso-water saturation contour map for the Bahariya Formation, Alam El Bueib Members, and Khatatba Formation

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The hydrocarbon saturations were determined using the following methodology:

$${\text{Shy}} = 1{-}{\text{Sw}}$$
(8)

In the analyzed region, a distinct trend of increasing hydrocarbon saturation is observed within the Bahariya Formation as one moves in the southeast direction. This saturation varies between 14 and 50%. Notably, the wells Bardy_W_1X and Bardy_D_1X_ST do not exhibit any net pay zones. Specifically, the ZAHRA_1X well records a hydrocarbon saturation of 48%, while the ZAHRA_E_D_1X well shows a saturation of 39%. In contrast, the Sanapl_1X well displays a significantly lower saturation level of 14%.

Within the Alam El-Bueib Member, there is an increasing trend of hydrocarbon saturation from east to west. Precisely, the Zahra_E_D_1X well indicates a saturation of 7%, the Zahra_1X well exhibits a saturation of 11%, and the Bardy_D_1X_ST well showcases a notably higher saturation of 90%. When considering the regional perspective, a similar trend of rising hydrocarbon saturation from east to west is observed in the Khatatba Formation. In particular, the Bardy area demonstrates a saturation level of 5%, whereas the Zahra area exhibits a significantly higher saturation level of 50%. Furthermore, the Bardy_D_1X_ST well displays a saturation level of 5%, the Zahra_E_D_1X well exhibits a saturation level of 32%, and the Zahra_1X well demonstrates a saturation level of 49%. A visual representation of these trends can be found in Fig. 12, which illustrates iso-hydrocarbon saturation contour maps.

Fig. 12
figure 12

Iso-hydrocarbon saturation contour map for the Bahariya Formation, Alam El Bueib Members, and Khatatba Formation

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5.2 Seismic interpretation and 3D structural modeling

The fusion of well data and seismic reflection plays a pivotal role in bridging the gap between stratigraphy and seismic interpretation in subsurface geology exploration and characterization. The integration of diverse data sources enriches our understanding of geological attributes, structural arrangements, and reservoir configurations within a specified research area. This investigation revolves around the harmonization of well data and seismic data, with the objective of interpreting seismic profiles, delineating stratigraphic layers, and elucidating fault patterns within the designated study zone. The principal goal of this study is to attain a comprehensive grasp of the geological composition and structure, ultimately offering valuable insights for reservoir modeling and analytical purposes (Western Geco 2011; Abdelhady et al. 2015; Abd El-Gawad et al. 2019; Gawad et al. 2021a, b; Reda et al. 2022; Mamdouh et al. 2023).

The process of harmonizing well data, which provides insights into subsurface conditions at various depths, with seismic data, capturing temporal subsurface information, marks a crucial initial step in establishing the correlation between stratigraphy and seismic reflection (Bredesen et al. 2015). Creating a seismic-to-well linkage enables the establishment of a connection between well data and seismic data, thereby enhancing the comprehensive interpretation of seismic profiles (Abdelwahhab and Raef 2020; Mamdouh et al. 2023). This integration of seismic data and well picks is greatly facilitated by the use of synthetic seismograms, which play a pivotal role in bridging these two datasets. The generation of synthetic seismic traces entails the convolution of reflectivity series, derived from acoustic and density logs, with extracted wavelets (White and Simm 2003).

The focal point of the analysis revolves around the Alam El-Bueib and Khatatba formations, which are meticulously examined using a well that offers a comprehensive dataset comprising acoustic and density records. Wavelets are extracted from the nearest seismic line, ensuring a precise connection between well data and seismic reflectors. This connection between the upper boundaries of stratigraphic layers and corresponding seismic reflectors is achieved through the utilization of one-dimensional synthetic seismograms, as illustrated in Fig. 13. The Zahra_1X well serves as an exemplary case of a seismic linkage, highlighting its alignment with the Alam El-Bueib Member as well as the Khatatba and Ras Qattara formations.

Fig. 13
figure 13

Synthetic seismogram operation, A location map for Zahra-1X Well, B wavelet, power spectrum, phase spectrum, and predictability, C synthetic seismogram log for Zahra-1X well; D synthetic seismogram to seismic section (in Line-5160) match log of Zahra

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The seismic sections illustrated in Fig. 14 provide insights into the predominant geological features of the region, which are characterized primarily by normal faults, occasionally accompanied by slightly elevated horst blocks. Fault boundaries define the majority of the fields within the research area, with some fields exhibiting trilateral structures and others displaying quadrilateral configurations. An interesting geological phenomenon observed in the Bardy area during the late Cretaceous period is the formation of a prominent horst structure resulting from the interaction of two opposing normal faults. Critical horizons, including the Abu-Roash “G” Member, Bahariya Formation, Kharita Formation, Alamein dolomite Formation, Alam El-Bueib members, Masajid Formation, Khatatba Formation, and Ras Qattara Formation, were meticulously selected for detailed interpretation (refer to Fig. 14). Through meticulous analysis and precise interpretation of seismic profiles, it has been determined that normal faults are the dominant fault type in the study region, with no other fault classifications identified.

Fig. 14
figure 14

Seismic cross sections covering the area of interest: ILNs: 5070, 5230, 5270; XLNs: 1150, 1310, 1330 seismic section

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Time maps were meticulously generated to monitor and analyze various horizons, ranging from deep to shallow depths across the studied segment. These horizons encompassed the Abu-Roash “G” member, Bahariya formations, Kharita formation, Alamein dolomite formation, Alam El-Bueib members, Masajid formation, Khatatba member, and Ras Qattara formation, as depicted in Fig. 15. The research area exhibits distinct gravitational faulting patterns, characterized by faulting orientations along the north–south, west–east, and east–west directions. These faulting patterns trace their origins back to the Jurassic period and persist into the subsequent Cretaceous period. Based on the available geological data, it can be inferred that these faults remained active from the upper Cretaceous to the lower Tertiary epoch. The presence of consistent fault orientations, such as the northeast-southwest trend, across structures originating from the Abu-Roash Formation and subsequent formations suggests a sustained stress regime. During the Tertiary period, several faults with a north-west to south-east orientation experienced reactivation, coinciding with structural activity observed in the Gulf of Suez. The formation of north-west to south-east faults in the study area can be attributed to the eruption of the Abu-Zaabal basalts during the early Cretaceous period, as documented by Abd El-Aal (1990) and Fathy (2012). A prominent geological feature within the Abu El Gharadig basin is the prevalence of north-west to south-east normal faults. The existence of multiple horizons in the region presents opportunities for further exploration and the identification of potential structural leads (refer to Fig. 15).

Fig. 15
figure 15

Two-way time map on the top of Bahariya I, IV, and VI Members, Alam El Bueib 3D Member, Masajid Formation, and Khatatba I Member

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The process of generating the final depth maps, as illustrated in Fig. 16, involved the application of optimal techniques for converting time maps into depth representations. These depth maps primarily aim to emphasize the relationship between depth and velocity, thereby providing valuable insights into the reservoir properties within the designated study region. It is crucial to acknowledge that the presence of hydrocarbons is not always directly correlated with the identified geological structures due to various factors. Challenges can arise from the presence of shale sand boundaries, which can impede the flow of oil and pose obstacles to drilling operations in the lower section of the geological formation or beyond the point of oil accumulation. Through a meticulous approach to selecting topographic maps of Bahariya formations, specifically focusing on the I, IV, and VI members, significant structures and potential leads were unveiled. These geological formations, including the Alam El-Bueib 3D member, Masajid formation, and Khatatba I member, were initially identified during the early Cretaceous and Jurassic epochs.

Fig. 16
figure 16

Depth map on the top of Bahariya I, IV, and VI Members, Alam El Bueib 3D Member, Masajid Formation, and Khatatba I Member

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The incorporation of seismic interpretations into structural modeling constitutes a fundamental step in the development of three-dimensional reservoir models. The primary objective of 3D structural modeling is to achieve a comprehensive analysis and understanding of the geological structure. The identification of fault patterns and structural horizons associated with hydrocarbon accumulation holds paramount importance in the construction of a reliable structural reservoir model (Cosentino 2001; Gawad et al. 2021a; Reda et al. 2022).

The process of structural analysis primarily relies on the interpretation of both two-dimensional (2D) and three-dimensional (3D) seismic data. The Petrel software application is frequently employed to implement sequential methodologies, including fault modeling, pillar gridding, the make zone process, and layering techniques (refer to Fig. 17). The utilization of this structural modeling procedure, which integrates seismic interpretations and fault data, has played a significant role in the development of a dependable three-dimensional reservoir model, thereby enhancing our understanding of the geological structure.

Fig. 17:
figure 17

3D structural model including pillar gridding, fault modelling, skeleton, and surface layering

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5.3 Fault seal analysis

In the study of clastic sequences, membrane seals, as highlighted by Watts (1987), are the predominant type of seal. The key determinant of seal failure is the capillary entry pressure of the seal rock, which signifies the pressure required for hydrocarbons to penetrate the most significant interconnected pore throat within the seal. Multiple mechanisms have been identified through which fault planes can function as effective membrane seals, as documented by Watts (1987) and Knipe (1992), Hesthammer and Fossen (2000), and Jones and Hillis (2003).

Firstly, the juxtaposition mechanism involves the positioning of reservoir sands in close proximity to a low-permeability unit characterized by a high entry pressure, such as shale. Detecting juxtaposition seals necessitates a methodical examination of the spatial arrangement of units along the fault plane. Secondly, clay smears occur when clay or shale becomes incorporated into the fault plane, resulting in increased entrance pressure within the fault. Thirdly, cataclasis entails the comminution of sand particles, leading to the formation of a fault gouge composed of finer-grained material. This imparts a higher capillary entry pressure to the fault. Lastly, diagenesis refers to the preferential cementation along an initially permeable fault plane, significantly impacting the entrance pressure.

Furthermore, it is essential to consider the examination of axial faults within the designated study region. In this region, three distinct faults are present, all situated on the western and northwestern periphery of the study area. Notably, these observed faults exhibit an unconventional orientation, diverging from the prevalent fault patterns observed in the surrounding region. This occurrence raises the possibility of an alternative tectonic event, either preceding or succeeding the tectonic activity that influenced the specific geographical area during the specified time period.

The influence of this fault extends throughout all strata, encompassing the deepest layers, intermediate zones, and shallower upper layers. The presence and implications of this fault are discernible in all seismic profiles, as illustrated in Fig. 18. Utilizing the Allan Diagram technique to analyze the fault under investigation, as presented in Fig. 20, it has been established that the region delineated by coordinates (X: 701,200 and X: 702,200 and Y: 272,250 and Y: 271,700) possesses permeability conducive to the migration of petroleum. Within this permeable area, there is a favorable juxtaposition of permeable layers on the downthrown side with equally permeable layers on the upthrown side. This pivotal zone represents a potential focal point for the migration of hydrocarbons from the Alam El Bueib members to the overlying sedimentary layers.

Fig. 18
figure 18

Base map showing traverse line passing through well locations and correlation between lithosaturation cross plots for Bahariya Formation for five wells

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This fault exerts its influence across all strata, extending from the deepest layers of the Alam El Bueib members, progressing through the intermediate layers, and culminating in the shallow upper layers of the Bahariya Formation. The precise location of this fault can be observed in Fig. 19, while the seismic section is depicted in Fig. 20. Through the application of the Allan Diagram technique for analyzing the fault in question, as illustrated in Fig. 21, it has been ascertained that the area enclosed by coordinates (X: 7,000,000 and X: 702,500 and Y: 268,500 and Y: 26,800) possesses permeability conducive to hydrocarbon migration. Within this permeable zone, there is a favorable juxtaposition of permeable layers on the downthrown side with similarly permeable layers on the upthrown side. Consequently, this pivotal region may function as a focal point for the migration of hydrocarbons from the Alam El Bueib members into the overlying sedimentary layers. From a fault seal perspective, the proposed well in the deep target area of Sanapl exhibits a favorable sealing condition along the same fault.

Fig. 19
figure 19

Top Alam El Bueib 3D depth map showing the investigated fault in the north-western part of the studied area (C.I. = 20 ft.)

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Fig. 20
figure 20

The interpreted seismic line (5230) showing the studied fault that located in the north-western part of the area in regional and zoomed lines

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Fig. 21
figure 21

Allan (Juxtaposition) Diagram (bed-fault intersections) for the investigated fault of Alam El Bueib in the north-western part of the area: A showing leakage points on Allan Diagram model, B showing the fault in 2D window

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6 Discussion

After interpreting all available data, the detailed TWT maps for the tops of traced reflectors show different structural closures, and these maps and some seismic attributes show that the area has almost tectonically ceased since the Cretaceous with a northwest-southwest faulting pattern, except for three main faults in the west. That may suggest that those three faults caused hydrocarbon migration from deep to shallow, so the intermediate target (Alam El Bueib) after those faults from north and northwest to east and southeast was dry in the center and east.

Using the data at hand, we conclude that the examined reservoirs in the southern Meleiha concession are characterized by: sandstone, siltstone, shale, and a few specks of limestone facies can be found in the Bahariya Formation, Alam El Bueib Member, Khatatba, and Ras Qattara. The Bahariya Formation is characterized by Shally Sand facies intercalations that result in the disappearance of reservoirs at close distances, requiring caution when locating a new well. Deep, middle, and shallow targets contained hydrocarbons, making Khatatba-Ras Qattara and Bahariya strata potentially rich, unlike Alam El Bueib members. The superficial objective Bahariya is considered to be the most accessible target in the area due to its position as the topmost layer of targets. Consequently, any faults or leaks in the geological structure provide an advantageous opportunity for the upper target to retain hydrocarbon resources.

The western section of the area Is where the majority of Alam El Bueib members live and work, whereas the eastern and southern parts of the region are unaccounted for. Leakage in the main three faults disrupted the migration pathway, allowing the hydrocarbon to escape from the intermediate to the shallow levels, which is what happened in the intermediate target Alam El Bueib members. Regarding the deep target, our stud’s three wells all have net pay sand, although they are geographically dispersed from east to west; this lends credence to the idea that the region is thoroughly traversed by a migration channel and indicates that the kitchen is functioning satisfactorily there. The purpose of this study is to validate the migration pathway and ascertain the causes of dry well failures subsequent to a fault seal analysis. Additionally, this study aims to identify the conceptual model and determine the optimal drilling location and layer. Based on a comprehensive examination and previous research conducted on the hydrocarbon system within the designated study area, it has been determined that the entire region has been impacted by secondary migration. This phenomenon has resulted in the complete filling of certain reservoirs with hydrocarbons, while adjacent reservoirs remain devoid of any hydrocarbon influence. This observation suggests that there are external factors beyond the migration process itself that have contributed to the failure of hydrocarbon accumulation within those specific reservoirs. Furthermore, when considering the integration of fault seal analysis, it was observed that faults located in the northwestern region of the study area exhibit hydrocarbon leakage. Consequently, the Bahariya and Khatatba reservoirs are deemed highly prospective as they have the potential to effectively trap and contain hydrocarbon deposits during their migration from the source to the reservoir. It is worth noting that the Alam El Bueib section, situated between these reservoirs, represents the most plausible and accurate model that aligns with the field data, indicating the occurrence of hydrocarbon escape through faults.

Consequently, we can delineate two distinct regions. The first region lies in the northwestern part, preceding the occurrence of transverse faults. This particular area has been subjected to the influence of oil migration. On the other hand, the second zone extends beyond the demarcation line within the interfacial rifts. It is important to note that hydrocarbons did not traverse this specific pathway during their migration process. The identification of novel opportunities for enhancing production through the exploration of untapped prospects is a key focus. From a structural standpoint, our analysis has revealed promising indications, leading us to propose the drilling of new wells in order to revitalize the fields within the designated research region, as seen in Figs. 22, 23 and 24. The concluding recommendations incorporate an assessment of the hydrocarbon-bearing layers that exhibit potential for oil presence, either through direct evidence or by virtue of their proximity to fields or businesses with established oil reserves. Nevertheless, there remains ample opportunity to identify novel leads across multiple levels that have yet to be investigated.

Fig. 22
figure 22

Top Alam El Bueib 3D Depth map showing the investigated fault in the west of the area of interest (C.I. = 20 ft.)

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Fig. 23
figure 23

The interpreted traverse seismic line coming from west direction to east in order to the migration pathway, showing the studied fault in regional and zoomed lines

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Fig. 24
figure 24

Leads on the top of Bahariya I, IV, and VI Members, Alam El Bueib 3D Member, Masajid Formation, and Khatatba I Member in 3D view

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The studied leads are considered to serve as a valuable reference for the unexplored areas, perhaps leading to the exploration of new horizons and the discovery of previously unknown fields within the region. As an illustration, feet were discovered within the Abu-Roush G member in a solitary field located in the Meleiha region. This finding indicates the presence of a specific void that facilitated the influx of oil into the reservoirs of the Abu-Roash “G" member, provided that the necessary conditions for an optimal reservoir were met. This presents novel opportunities for us to monitor leads across all categories while searching for atypical instances. The Jawaher North field, which contains the Abu-Roash (G) member with some pay, is situated in the middle region of our designated study area. Consequently, we acknowledge the oil-bearing nature of the Abu-Roush (G) member and endeavor to identify potential causes of failure in adjacent fields.

The comprehensive projections are presented in Table 4. The Bahariya region consists of six distinct layers, namely Bahariya I, Bahariya II, Bahariya III, Bahariya IV, Bahariya V, and Bahariya VI, arranged in a vertical sequence. The units of interest for our interpretation are Bahariya I, Bahariya IV, and Bahariya VI. Subsequently, it is possible to make predictions among these entities. By conducting a meticulous analysis of multiple strata within the Bahariya formation, we have identified six novel avenues that hold promise for advancing research in the designated study region. One notable benefit of these leads is their occurrence in several layers at varying levels, thereby providing corroborating evidence of their existence in the physical realm. The Kharita zone within our study region does not exhibit hydrocarbon-bearing characteristics. However, it can serve as a valuable indicator for identifying the base zones of the Bahariya formation that contain oil in the base units, such as the Zahra field and Zahra-E-D field. Additionally, the aforementioned resource can be utilized as a viable water source for the nearest wells. Furthermore, it is worth noting that the top Kharita map reveals the presence of twelve newly identified leads or aquifers.

Table 4 Prospect and lead description in the Baharyia Formation in the Meliha concession
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Table 5 is utilized to establish a correlation between the leads found in Alamein dolomite and Alam El-Bueib, taking into account their close proximity. The top Alam El-Bueib components, namely Alam El-Bueib I and Alam El-Bueib IIB, as well as specific wells such as Zahra-1X and N-Zahra-1X, contain hydrocarbons. There are a total of 16 leads available at this particular level for the purpose of developing the region. These leads are consistently present across all members of El-Bueib, but with a minor horizontal displacement. There are a total of nine leads identified in the study. Among these leads, a subset is located within the Alamein dolomite formation. Additionally, it is seen that the top Alam El-Bueib lead is also present in Alam El-Bueib 3A, perhaps due to the very tiny thickness separating them. In the Alam El-Bueib 3D reservoir, there are a total of seven leads identified. It is worth noting that several leads were first identified in the 3E layer, mostly due to the relatively narrow separation between them. In addition, there are six leads inside the Masajid layer that present potential avenues for area development. The leads and structures discussed in this context serve as valuable evidence for the exploration and development of the closest hydrocarbon-bearing levels. This is due to their direct correlation with the formations found during the late Jurassic period, specifically the Masajid-Sidi Barrani formation, particularly Khatatba IIB, IIC, and IID. The seismic reflector brightness seen at the Masajid zone serves as a valuable indicator for locating the deep target during the interpretation of Khatatba.

Table 5 Prospect and lead description in the Alam El-Bueib 3D/3E members in the Meliha concession
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There are a total of 13 leads identified inside the Khatatba formation, namely within the Khatatba III member. These leads hold potential for development in the deep target region. The reliability of these leads is supported by the fact that the structures they exhibit align closely with leads observed in the Masajid formation. Furthermore, these structures directly reflect the characteristics of the underlying layers, particularly when they are in close proximity. This information is summarized in Table 6. From a structural perspective, the outcome of lead generation yielded various types of leads across different levels. Our recommendation entails identifying additional drilling sites that can target several objectives within the geological column. This approach aims to minimize costs and the projected number of wells required. In the case of wells that are designed to target multiple levels, it is customary to assign a hierarchical ranking based on their relative relevance. These wells can either have a single target or multiple targets. Within the Meleiha concession region, a total of 37 wells have been identified and designated in a sequential manner, ranging from well 1 to well 37. These wells exhibit a transition from multi-target to single-target drilling objectives. The recommended coordinates for the significant locations are shown in Table 7. The initial seven leads are directed at three specific objectives, namely Bahariya, Alam El-Bueib, and Khatatba. Subsequently, the following eighteen leads, numbered from 8 to 25, exclusively focus on two stacked leads. There are four leads that are focused on Bahariya and Alam El-Bueib, namely from 8 to 11. Additionally, there are 10 leads, ranging from 12 to 21, that are targeting Alam El-Bueib and Khatatba. Four expeditions are focusing their efforts on the regions of Bahariya and Khatatba, namely from the 22nd to the 25th. The most recent twelve leads only focus on a single lead, with three pertaining to Bahariya, two to Alam El-Bueib, and seven to Khatatba.

Table 6 Prospect and lead description in the Khatatba and Ras Qattara formations in the Meliha concession
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Table 7 Description of the lead’s coordinates, well types and number of targets
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7 Conclusions

This work stands out for its profound contributions to the understanding of the southern Meleiha concession, introducing a multitude of novel insights in the field of hydrocarbon exploration. The study encompasses a wide spectrum of geological formations, spanning from the Late Cretaceous Bahariya Formation to the Permo-Jurassic Khatatba and Ras Qattara Formations, providing a comprehensive examination of Mesozoic and Cenozoic rock formations in Egypt's northern Western Desert. The identification of three distinct tectonic deformations in northern Egypt, coupled with the use of advanced digital well-logs and seismic lines, underscores the innovative methodology employed.

The study's findings regarding petrophysical parameters in the Bahariya Formation, Alam El Bueib members, and Khatatba–Ras Qattara formations indicate net pay thicknesses of 43, 28, and 12 feet, respectively. Additionally, the effective porosity of the examined reservoirs falls within the range of 10–18%. Water saturation levels vary from 10 to 98%, while hydrocarbon saturation levels reach up to 48%, 90%, and 49%, respectively. Cross plots derived from the study support these findings, providing mutual corroboration. The presence of hydrocarbons in the deep, middle, and shallow target areas suggests significant potential in the Khatatba-Ras Qattara and Bahariya layers, while the Alam El Bueib members exhibit varying hydrocarbon richness. The study employed 30 seismic lines to elucidate the structural framework and enhance hydrocarbon sequestration in the arid region located south of the Mediterranean Sea. The seismic interpretation revealed a prevalence of normal faults in the area, occasionally accompanied by slightly elevated horst blocks. Field structures within the study region exhibited both triangular and quadrilateral configurations, separated by fault boundaries. The leads were identified based on primary reflectors, and the seismic lines exhibited predominant orientations along the north–south and east–west directions. The geological formations encompassed various late Cretaceous tectonic features, including Abu-Roush “G” Bahariya 1 member, Bahariya 4 member, Bahariya 6 member, Kharita formation, Alamein dolomite formation, Alam El-Bueib 3A, 3D, and 3G members, Masajid formation, Khatatba-2D member, Ras Qattara formation, and additional formations not specifically mentioned. The bidirectional temporal maps revealed promising locations for untapped oil exploration and extraction activities. Bahariya, as the shallowest target, is accessible and considered one of the most promising layers in the region. However, the presence of Shally Sand facies intercalations necessitates caution when determining well locations due to potential reservoir disappearance at short distances. The net pay zones of Alam El Bueib members are concentrated in the western region of the study area, with an absence in the east and southeast. Leakage in the main three faults disrupted the migration channel in the intermediate target Alam El Bueib members, diverting hydrocarbons towards the shallow areas. The Khatatba-Ras Qattara formation, characterized as a deep target, is a significant geological feature of interest. The study focused on three wells within this formation, all of which exhibited net pay sand. These wells were distributed across the study area, spanning from east to west, supporting the hypothesis of extensive migration pathways throughout the region and indicating a well-functioning hydrocarbon source. In total, there are 37 potential drilling locations across all levels. Some wells have multiple targets, while others are focused on a single objective.