Класс Месторождения: Уникальное
Тип Месторождения: Нефтегазоконденсатное
Местоположение:
Местность:
Стадия разработки: Добыча
Год открытия: 1961
Источник информации:
Метод открытия:
Площадь: 68.07 км²
Belayim Marine Oil Field
The Belayim Marine Oil Field is located in the eastern side of the Gulf of Suez (Fig. 1b), 165 km southeast of Suez City. The research study aims to improve the resolution of the basin architecture and understanding of the basin history of this prolific producing area of the Gulf of Suez of Egypt, through the application of the Petroleum System Modeling (PSM).
The occurrence of oil is linked to the tectono-stratigraphic history of the Gulf of Suez basin, which has created multiple reservoirs and seal combinations. Adequate potential source rocks are spatially widespread in the area with two major oil types identified (Abu Al-Atta et al. 2014).
Geologic framework
The present-day Gulf of Suez rift, together with the Red Sea oceanic basin and the Aqaba-Dead Sea transform systems, comprise the Sinai triple junction, which initiated during the northeasterly movement of Arabia away from Africa. The age of such movements is mainly Neogene (Fichera et al. 1992).
The Gulf of Suez rift lies within the Arabian-Nubian shield, a segment of upper Proterozoic to Lower Paleozoic continental crust formed during the widespread Pan-African tectono-thermal event; this crust forms the basement of much of northeast Africa and western Saudi Arabia (Engel et al. 1980; Gass 1981). Pan-African tectono-thermal event was mentioned during (580–570 Ma) (IHS 2006). This segment of crust developed through the progressive cratonization and accretion of numerous intraoceanic island arcs and Andean-type magmatic arcs during the interval of 900–550 Ma (Engel et al. 1980; Gass 1981). The basement complex, with the exception of the basic intrusives, is generally accepted to be Precambrian in age from 620 to 580 Ma (IHS 2006).
The pre-rift sediments were deposited in continental margin sag basins at the southern margin of Tethys/Neo-Tethys in at least two cycles of subsidence commencing in the Cambrian. The first groups of clastic sediments are usually referred to as Nubian B, Nubian C, and Nubian D and are probably all Paleozoic in age from 570 to 299 Ma. The second major phase of pre-rift sedimentation commenced in a successor basin in Early Cretaceous times. An essentially northward thickening wedge of dominantly marine sediments, commencing with the clastics of the Nubian A and comprising both clastics and carbonates, was deposited more or less continuously from Albian-Aptian times to Late Eocene (IHS 2006). The final group, the Nubian A, is dated as mid-Late Jurassic and latest Early Cretaceous. An unconformity exists between the Nubian A and the Nubian B, plus unconformity exists between the Nubian B and the Nubian C (Patton et al. 1994). There is evidence for two phases of Hercynian tectonics affecting the distribution of Nubian sediments: the first phase was during 443–336 Ma and the second phase of the Hercynian tectonic event was during 299–260 Ma.
The Late Permian to Early Triassic (Permo-Triassic) Quisib red shale member of Nubia A Formation was deposited from 260–245 Mabp. The Gulf of Suez regional uplift tectonic event was during the time from 245 to 145 Mabp (Fig. 1) (IHS 2006). The Late Jurassic Early Cretaceous uplift resulted in a hiatus in the geological record. During the Aptian time, sedimentation renewed and alluvial sediments of the Malha Formation (Aptian-Albian) from 145 to 99 Mabp were deposited over rocks ranging in age from the Precambrian to Jurassic (Patton et al. 1994). The regional northward tilting event was for the duration of time from 99 to 97 Ma (Fig. 1), where from 97–50 Ma stress becomes compressional and resulted in fold-anticline (IHS 2006). This genetic unit is characterized by at least two phases of thermally driven subsidence at divergent plate margins (southern margins of Tethys and Neo-Tethys) ending with the collision between the African and Eurasian plates (88.5–39 Ma). The dominant deformation during the Syrian Arc folding (Early Late Cretaceous to Early Eocene) was a north-south compression, swinging to north-northwest to south-southeast. The principal structures were folds with axes oriented approximately west-south-west-east-northeast. Geochronologically Pre-rift Continental Margin Sag Unit continued to 35.4 Ma. The Gulf of Suez rift was then initiated by lithospheric stretching in latest Oligocene times followed by extensionally driven subsidence, which commenced in earliest Miocene times.
Fig. 1 Lithostratigraphic column and tectonic correlation chart of Belayim Marine Oil Field, Gulf of Suez, Egypt. The facies succession, ages,
distribution of potential source, and reservoirs rocks are also represented (IHS 2006)
After this initial phase of subsidence, there was a period of isostatic uplift on the rift shoulders and some rearrangement of the rift blocks during the Early Miocene, before renewed extensional subsidence, which ended in the mid-Miocene.
Active divergent continental margin (gravitational subsidence) was ranging in age from 29.3 to 14.2 Ma (IHS 2006).
The Syn-rift Unit is characterized by the initial extension due to lithospheric stretching, at the northern extremity of the East African-Red Sea Rift System, followed by isostatic uplift of the rift shoulders (17 Ma). The rifting commenced in the pre-Miocene, with the maximum tectonic subsidence, accompanied by magmatic events, occurring in the Late Oligocene to Early Miocene (Gandino et al. 1990). Subsidence may have continued until the Late Neogene. The interpretation of the phases of tectonic subsidence and their periods and structural stages during the late Tertiary are shown in (Fig. 3). The Suez rift was initiated between 24 and 21 Mabp, that is, latest Oligocene to earliest Miocene (Evans 1990). The uplifting of rift shoulders was through the time from 21 to 20 Mabp) (Fig. 1) (IHS 2006). Between 20 and 17 Mabp, the flanks of this basin began to rise because of heating effects (Steckler 1985). Several unconformities interrupt the sedimentary record, with major ones in the Paleozoic, Triassic-Jurassic, Oligocene, and Late Miocene (Messinian). These basin-wide unconformities formed primarily in response to regional tectonic adjustments associated with different rift phases of the Gulf of Suez (Dolson et al. 2001). Rifting was caused by tensional stresses transmitted through the lithosphere, accompanied by an upwelling of hot asthenosphere. Both the crystal extension and tectonic subsidence of the axial trough reached their maximum development between 19 and 15 Mabp (Steckler et al. 1988).
Fig. 2 The relationship between tectonic subsidence rates, types, periods, climate, and sea level changes during the Neogene in the Gulf of Suez (compiled and modified from (Bosworth et al. 1998; Griffin 1999). Smaller V symbols represent periods of rapid basin subsidence, for example, the Burdigalian; larger V symbols represent modest rates of basin subsidence, for example, in the Serravallian
A further pulse of extension ended in the Middle Miocene (14.2 Ma). The principal structures formed during this period were tilted fault-blocks, half-grabens, rollover, and other accommodation structures in hanging wall blocks. A number of other trends are commonly reported, of which the most important are the Aqaba Trend (020°–200°) and the so called cross trend (050°–230°) (IHS 2006). At this time from 14.2 to 14 Ma, Suez phase extension terminates and Aqaba transverse begins (Fig. 2) (Bosworth et al. 1998; Griffin 1999). Further extension of fault-block rotation tectonic event is at 14.2 Ma (Fig. 1) (IHS2006). The period (14.2–5.2 Ma) is characterized by post-rift thermal subsidence, during a period of relative quiescence on the whole Red Sea rift system. The principal structures are rollover and other accommodation structures in hanging-wall blocks of re-activated faults, and compaction/ subsidence-driven structures. Following Kareem deposition, there appears to have been another period of relative uplift resulting in local unconformity at the top of the Kareem Formation. Thereafter, the dominant control appears to have been post-rift thermal subsidence, during a period of quiescence on the whole Red Sea Rift System, until the latest Miocene time when the Red Sea Rift System again became active. This relative uplift may have been responsible for establishing a barrier that isolated the Suez Rift from its former open link to the Mediterranean. The result of the barrier was the end of normal marine conditions in the Gulf and the first phase of massive evaporite deposition. Within the first of the evaporite units, the Belayim Formation, there were, however, two periods of normal marine deposition, the last of which produced important carbonate reservoir facies in the form of algal buildups on the crest of tilted pre-Miocene fault-blocks.
Thermal subsidence time is 11.4–10.7 Ma according to (IHS 2006) (Fig. 1). Post-Belayim deposition consists of two further evaporitic units, the South Gharib Formation (dominantly halite) and the Zeit Formation (interbedded anhydrites and clastics, with minor halite). These evaporites are the key sealing facies in the basin (Fig. 1) (IHS 2006). By 5 Ma, Aqaba-Dead Sea transform fault replaced the Gulf of Suez as the primary plate boundary between the African and Arabian plates (Evans 1990). The period 5.2–0 Ma is characterized by subsidence driven dominantly by cooling following active rifting, but with an overprint of locally renewed extensional faulting in the south of the basin from 5.2 to 4 Ma. The main structures include half-grabens, drape structures, and modification of existing block traps through the rejuvenation of bounding faults (IHS 2006). A pronounced unconformity is recognized at the top of the Zeit Formation, before renewed subsidence and accumulation of Plio-Pleistocene clastics commenced. This renewed subsidence appears to reflect the resumption of extension and sea floor spreading in the south of the Red Sea Rift System. Although the bulk of the extension in the Red Sea appears to have been accommodated by movements on the Dead Sea-Gulf of Aqaba transform, there is evidence for renewed extension in both the north and south of the Gulf of Suez, from about 5 Ma to present. In the south, a number of faults cut the seabed and earthquake data shows there is active faulting at the present. In the north, the very large thicknesses of Zeit Formation and post-Zeit sediments (EL-Tor Group) adjacent to the Darag Fault, following negligible deposition of South Gharib sediments, points to renewed extension (Fig. 1) (IHS 2006).
The evolution of the Gulf of Suez basin is in stages from the Paleozoic to the Holocene and is characterized by tectonic extensional episodes producing tension block faulting (horst and graben) and block subsidence (Fig. 3) (see also (Kingston et al. 1983)). The Gulf of Suez has developed in a series of distinct evolutionary stages as shown in Fig. 3.
Fig. 3 Development stages of the Gulf of Suez, as an example of a typical interior fracture rift basin (Alsharhan 2003)
Data source: Thermal maturity and hydrocarbon generation of the Dawi Formation, Belayim Marine Oil Field, Gulf Of Suez, Egypt: a 1D Basin Modeling Case Study. Mohamed Moustafa Afife, Mohamed Abu Al-Atta, Mohammed A. Ahmed, Ghalib Ibrahim Issa. Arab J Geosci. 2016
Следующее Месторождение: Sahabi (095-D)