bluuebunny/crossref_metadata_2025_split huggingface dataset:
Subsalt Depth Imaging Using 3-D VSP Technique in the Ras El Ush Field, Gulf of Suez, Egypt
Authors: Badri Mohammed A. , Taha Taha M. , Wiley Robert W. 
Published: October 2021

ABSTRACT
In 1995 oil was discovered in the pre-Miocene Matulla and Nubia Sandstones in the Ras El Ush field, Gulf of Suez, Egypt. The discovery was based on an aeromagnetic anomaly from a basement high. After drilling several delineation wells, based on a geological model, it became evident that the field is very complex as it is broken into tilted and rotated compartmental blocks by two perpendicular fault systems. Also the 2-D seismic data were of poor quality beneath the thick Miocene South Gharib Evaporite. Since part of the field lies below shallow-water, 3-D seismic was considered to be too costly. When a delineation well did not encounter the reservoir, due to an unanticipated fault, a 2-D walkaway Vertical Seismic Profile (VSP) was acquired. It clearly revealed the presence of a cross fault. The success of the 2-D VSP in imaging the fault led to the acquisition of the first Middle East 3-D VSP survey in the following well. A downhole, tri-axial, five geophone array tool was used to acquire the 3-D VSP. The 3-D volume of the final migrated VSP data provided the means for the reliable mapping of horizons beneath the South Gharib Evaporite. These maps improved the definition of the field and helped detect previously unrecognized prospective blocks. Four further successful delineation wells confirmed the 3-D VSP interpretation.
Carbonate Platform to Basin Transition along an Upper Cretaceous to Lower Tertiary Syrian Arc Uplift, Galala Plateaus, Eastern Desert of Egypt
Authors: Kuss Jochen , Scheibner Christian , Gietl Ralf 
Published: October 2021

ABSTRACTBiostratigraphic and facies analyses were made on Upper Campanian to Lower Eocene strata along a 58-kilometer-long dip transect across the Northern and Southern Galala plateaus, west of the Gulf of Suez. The analyses enabled us to reconstruct the evolution of a platform–slope–basin transition that is roughly parallel with the trend of the plateaus. We interpret individual sedimentary cycles as processes of a southward-prograding carbonate platform that developed along a branch of the Syrian Arc Fold Belt. The Northern Galala area was a structural high as shown by hiatuses spanning Late Cretaceous (Coniacian) to Early Paleocene times. To the south, carbonate platform progradation is evident from the Late Campanian onward. Late Cretaceous platform-derived slope deposits interfinger with basinal chalks and calcareous shales farther south. Early Tertiary carbonates were deposited in platform, slope, and basin settings. The evolution of the platform–slope–basin transition is documented by the changing large-scale depositional geometry. The evolution occurs within sedimentary sequences that are interpreted by means of a high-resolution biostratigraphic framework. The facies architecture reflects the evolution from a rimmed shelf (Late Cretaceous) to a distally steepened ramp (latest Cretaceous to Paleocene) and eventually to a homoclinal ramp (Early Eocene). The reconstruction of the imprint of fluctuating sea levels on the sedimentary record has been used to establish comparisons with age-equivalent cycles from neighboring regions.
Albian-Cenomanian Palynology, Paleoecology and Organic Thermal Maturity of Well DK-B in the Dukhan Oil Field of Western Qatar
Authors: Ibrahim Mohamed I.A. , Al-Hitmi Hind H.A. , Kholeif Suzan E. 
Published: October 2021

ABSTRACT
A palynological investigation of the Nahr Umr, Mauddud and Ahmadi formations of the middle Cretaceous Wasia Group in Well DK-B in the Dukhan oil field of Qatar, yielded 30 species of dinoflagellate cysts, 18 of pteridophytic spores, 14 of gymnosperm pollen, and 16 of angiosperm pollen. Based on the investigation, the age of the Nahr Umr Formation is middle to late Albian. The basal part of the Formation was deposited in a marine prodelta or shallow shelf environment, whereas sedimentation of the upper part took place in normal marine conditions of an inner to middle shelf at depths of 10 to 80 meters. The carbonates of the Mauddud Formation are of late Albian (Vraconian) to early Cenomanian age and were deposited in an inner-middle shelf environment (20–100 meters). The shales and limestones of the Ahmadi Formation are of early to middle Cenomanian age and accumulated in open-marine conditions within an outer-shelf environment (100–200 meters). Two regressive pulses or lowstand system tracts can be detected in the lower and middle parts of the Ahmadi Formation that are consistent with published short-term global eustatic curves. Rocks of the Wasia Group studied in Well DK-B are in general enriched in kerogen type II (oil-prone material) except for the lower part of the Nahr Umr Formation that can be attributed to kerogen type III (gas-prone material). The thermal alteration index range of 2, 2+ to 3− suggests that the sediments of the Ahmadi Formation are immature whereas those of the Mauddud and Nahr Umr formations are slightly mature. The Albian-Cenomanian palyno-assemblage of western Qatar is referable to the African-South American Phytogeoprovince as shown by the presence of Crybelosporites pannuceus, ephedroid pollen, elater-bearing pollen, Afropollis, Stellatopollis, Reyrea and Cretacaeiporites species. Arid to semi-arid (tropical to subtropical) climatic conditions prevailed in the African-South American province at this time. Dinoflagellate cysts suggest a Tethyan connection.
Essay: applied cyclo-stratigraphy for the Middle East E&P industry
Authors: Mattner Joerg , Al-Husseini Moujahed 
Published: October 2021

Summary
The modeling of ordered sedimentary cycles through orbital forcing (cyclo-stratigraphy) could impact the Middle East E&P industry practices from regional exploration to reservoir engineering. The correlation of longer period cycles could detect thinning or disappearing reservoir intervals over structures. These terminations may be due to erosion or non-deposition, and used to guide exploration for stratigraphic traps. The correlation of shorter period cycles may be used to map the disappearance or diagenetic alteration of reservoir flow units between wells. The Permian and Mesozoic carbonates and evaporites that constitute the main Middle East hydrocarbon reservoirs and seals, manifest cycles at many scales, and are particularly suited for cyclo-stratigraphic analysis.
Genesis and characterization of dolomite, Arab-D Reservoir, Ghawar field, Saudi Arabia
Authors: Cantrell David , Swart Peter , Hagerty Royal 
Published: October 2021

ABSTRACT
This study reports the results of an investigation into the nature, origin and significance of linear dolomite trends across the Arab-D reservoir in Ghawar field. In the course of this study, three distinct types of dolomite were identified based on petrographic and geochemical criteria: fabric-preserving (FP), non-fabric-preserving (NFP) and baroque dolomite. Fabric-preserving (FP) dolomite is very finely crystalline dolomite in which details of the original limestone fabric are usually well preserved. Beds of FP dolomite typically occur as thin, sheet-like or stratigraphic layers that are always intimately associated with the overlying anhydrite. This dolomite is interpreted to have formed very early in the diagenetic history of the sediment, by dense, highly evaporated magnesium-rich brines associated with the overlying anhydrite. In contrast, NFP dolomite is a medium crystalline, non-baroque dolomite in which all traces of the original limestone fabric have been obliterated. This dolomite also typically occurs as stratigraphic beds, although it is not restricted to the uppermost part of the Arab-D but occurs throughout the reservoir. The NFP dolomite is the most common type present in the reservoir, and is interpreted on the basis of its general geochemical similarity to the FP dolomites to have mostly formed from hypersaline fluids, although some NFP dolomite is thought to represent a transitional form with the third dolomite type, baroque dolomite. Strontium isotopic ratios suggest that both the FP and most of the NFP dolomite formed very early, at or shortly after deposition of the original sediment. The third type of dolomite, baroque, is a coarsely crystalline dolomite with “saddle-shaped” crystals displaying undulose extinction in thin section. It is rare in the reservoir and appears to be limited to wells that contain abnormally thick sections of dolomite; in extreme cases, baroque dolomite is vertically pervasive. Geochemically, baroque dolomite is distinctive with high iron and very low oxygen isotopic compositions, and is interpreted to have formed from high temperature fluids during burial diagenesis. These fluids are suggested to have ascended up into the reservoir from depth along a fault/facture system, relatively late in the diagenetic history of the rock.
Preferential deposition and preservation of structurally-controlled synrift reservoirs: Northeast Red Sea and Gulf of Suez
Authors: Stephen R.Polis , Michael T.Angelich , Charles R.Beeman , William B.Maze , David J.Reynolds , David M.Steinhauff , Andrei Tudoran , Mark V.Wood 
Published: October 2021

ABSTRACT
An integrated GIS-based play evaluation, which incorporates restorations of the North Red Sea and Gulf of Suez, has helped to identify potentially prospective areas in the Northeast Red Sea associated with point-sourced synrift sandstone reservoirs. The three largest synrift Gulf of Suez fields (Belayim Land, Belayim Marine, and Morgan) are located along major fault-transfer zones that optimized the conditions for the deposition and preservation of thick point-sourced sands adjacent to extensive hydrocarbon source kitchens. Belayim Land and Morgan fields contain stacked submarine fan, delta, and alluvial fan systems that developed during the deposition of the Miocene Rudeis, Kareem, and Belayim-South Gharib formations, respectively. This continuous, point-sourced sedimentation is indicative of stable drainage and by inference, a stable eastern border fault system. We attribute this stable border fault system to a stress heterogeneity related to the pre-existing Najd Shear Zone, and polarity reversals in upper-plate transport direction.
Tectonic restorations indicate that the North Red Sea, like the Gulf of Suez, should have reservoir facies deposited in similar structural positions, but preservation is a significant risk due to additional crustal extension. Although crestal block erosion remains a great concern for reservoir preservation, seismic mapping indicates that block size along the coastal region and inboard areas are similar to the Gulf of Suez. This suggests that most of the strain may have been accommodated along the warmer axial portion of the rift where weaker crustal rheology exists.
Landsat mapping of the Northeast Red Sea border fault system has found a high degree of variability in structural styles. The southern Yanbu-Jeddah and Umm Luj-Al Wajh sub-basins are bound by listric, down-to the west-southwest border faults, separated by suture-controlled accommodation zones. To the north, the Midyan-Ifal sub-basin is located along the Miocene flexural margin, and is structurally more complex. Northwesterly-trending (Najd Shear Zone) planar faults are overprinted by a strong northeasterly (Aqaba) trend, such that transpressional and transtensional features exist. Although structurally complex, the offshore northern flexural margin has been determined to have the best potential for localized, second-generation, thick, synrift sediments similar to that of the Gulf of Suez.
Lithostratigraphy of the Red Sea Region
Authors: Hughes Geraint Wyn ap Gwilym , Johnson Robert S. 
Published: October 2021

ABSTRACT
The onshore and offshore Saudi Arabian Red Sea region contains a series of lithostratigraphic units that have not previously been formally defined and described. Based on an intensive study of the succession, a lithostratigraphic scheme is proposed in a lexicon format that integrates biostratigraphic, sedimentological, seismic and field studies from the Midyan Peninsula in the north, to the Jizan Coastal Plain in the south. In view of the economic aspect of the Neogene succession and greater accessibility to Neogene subsurface samples, emphasis has been placed on a revision of the Neogene lithostratigraphy. Resting upon Proterozoic Basement, the sedimentary succession was deposited during the Cretaceous to Pleistocene times. The oldest pre-rift Suqah Group nonconformably overlies the Proterozoic Basement and consists of Upper Cretaceous shales of the Adaffa Formation and Cretaceous to Palaeogene sandstones, shales and thin limestones of the Usfan Formation. A series of volcanics includes the early to middle Oligocene Matiyah Formation and the late Oligocene-early Miocene Jizan Group.
The Neogene succession displays a great lithological diversity. The Tayran Group (Al Wajh, Musayr and Yanbu Formations) includes marginal marine siliciclastics of the Al Wajh Formation, and represents the earliest rift-associated sediments deposited during the earliest Miocene. These are conformably overlain by lower Miocene shallow-marine carbonates of the Musayr Formation. In some of the central Red Sea onshore basins, thick lower Miocene submarine evaporites of the Yanbu Formation were deposited under locally restricted conditions and form the third formation of the Tayran Group. Rapid subsidence during the early Miocene caused deposition of deep-marine, planktonic-foraminiferal mudstones and thick submarine fan sandstones of the Burqan Formation. Carbonates, marine mudstones and submarine evaporites of the Maqna Group (Jabal Kibrit and Kial Formations) unconformably overlie the Burqan Formation and were deposited during latest early Miocene to earliest middle Miocene. The Jabal Kibrit Formation consists of an anhydrite-carbonate facies, of which the carbonates form the Wadi Waqb Member. Siliciclastic facies of the Jabal Kibrit Formation are termed the Umm Luj Member. Above the Jabal Kibrit Formation, the Kial Formation is typified by interbedded anhydrites, calcareous siltstones and carbonates, and includes the Sidr, Nakhlah, Yuba, Rayaman and Sabya Members. Within the region, thick evaporites of the Mansiyah Formation were deposited extensively during the middle Miocene, and are overlain by poorly exposed sands, shales and thin anhydrite beds of the middle to upper Miocene Ghawwas Formation. The Lisan Group unconformably overlies the Ghawwas Formation and consists of coarse alluvial sands and gravels of possible Pliocene to Holocene age.
Iran’s crude oil reserves and production
Authors: Al-Husseini Moujahed I. 
Published: October 2021

ABSTRACT
The Government of Iran estimates the country’s initial-oil-in-place and condensate-in-place are about 600 and 32 billion barrels (Gb), respectively. In 2004, the official estimate of the proved remaining recoverable oil and condensate reserves was about 132.5 Gb, of which crude oil accounted for about 108 Gb. Cumulative crude oil production is expected to cross the 60 Gb mark in 2007, implying that the estimated ultimate recoverable reserves of crude oil are about 168 Gb (cumulative production plus remaining reserves) and the total recovery factor is about 28%. The main Oligocene-Miocene Asmari and Cretaceous Bangestan (Ilam and Sarvak) reservoirs contain about 43% and 25%, respectively, of the total crude oil-in-place. Recovery factors for the Asmari range between about 10–60%, and for the Bangestan between 20–30%. Between 1974 and 2004 remaining recoverable reserves have increased from about 66 to 108 Gb, while the ultimate recoverable reserves have increased from 86 to 168 Gb.
In contrast to 1974 when Iran’s production peaked at 6.0 Mb/d, production in 2005 averaged about 4.1 Mb/d. The 1974 peak occurred when production from most of the giant fields was ramped-up to very high but unsustainable levels. Current plans are to increase the crude oil production rate to 4.6 Mb/d by 2009. This is a significant challenge because this production capacity has to offset a reported total annual decline rate of 300–500,000 barrels/day (Kb/d). This high decline rate is attributed to the maturity of the giant fields, many of which attained their peaks in the 1970s and have produced about half or more of their estimated ultimate recoverable reserves. Therefore to achieve the 2009 production target within the next three years, Iran has to add about 680 Kb/d of capacity per year from its developed fields (infill drilling, recompletions, enhanced and improved oil recovery), while also adding net new surface facilities and well capacity from undeveloped fields and reservoirs.
Microfacies and sedimentary environments of the late Oligocene-early Miocene Qom Formation of the Gooreh Berenji region (Jandaq area, central Iran)
Authors: Alireza Shakeri , Jalal Douraghinejad , Mehran Moradpour 
Published: October 2021

ABSTRACT
The late Oligocene-early Miocene Qom Formation in the Central Iran Basin contains oil and gas in the Alborz and Sarajeh fields. Organic geochemical analyses in previous studies indicated that the hydrocarbons migrated from deeper source rocks, likely of Jurassic age. In the Central Iran Basin, the Qom Formation is 1,200 m thick and is bounded by the Oligocene Lower Red Formation and the middle Miocene Upper Red Formation. In previous studies, the Qom Formation was divided into nine members designated from oldest to youngest: a, b, c to c4, d, e and f, of which “e” is 300 m thick and constitutes the main reservoir. Our study focused on a Qom section located in the Gooreh Berenji region of central Iran which is 294 m thick. The lower part of the formation was not deposited, and only the following four members of early Miocene age (Aquitanian and Burdigalian) were identified between the Lower and Upper Red formations: “c2”? (mainly greyish to greenish gypsiferous marls); “d” (thin- to thick-bedded anhydrite with intercalation of thin-bedded sandstone); “e” (argillaceous or sandy limestone); and “f” (fine-grained coral and bryozoan boundstone). In contrast to the Central Iran Basin, the “e” member in Gooreh Berenji is only 15 m thick and does not have a good reservoir potential.
A detailed petrographic analysis of the Gooreh Berenji section resulted in the identification of 13 microfacies (MF) that were interpreted in terms of their depositional environments according to the following categories: MF1 (sabkha), MF2 (intertidal river channel), MF3 (lower intertidal), MF4 (peritidal), MF5 (supratidal), MF6 and MF7 (shallow restricted lagoon), MF8 and MF10 (proximal open-marine), MF9 (leeward lagoon), MF11 (shoal), MF12 (reef and patch reef formed within lagoon), and MF13 (open-marine). The Qom Formation constitutes a regional transgressive-regressive sequence that is bounded by two continental units (Lower and Upper Red formations). The transgression started from the south in the late Oligocene and by the early Miocene the sea covered all of central Iran. In the Gooreh Berenji area, carbonate deposition occurred on a shallow-marine ramp. The presence of a wide range of lagoonal facies indicates that reefal facies (“f”) developed in a narrow elongated strip away from the shoreline.
Colour change in the acritarch Veryhachium as an indicator of thermal maturity
Authors: Duggan Catherine M. B. , Clayton Geoff 
Published: October 2021

ABSTRACT
Veryhachium is an acritarch genus that occurs commonly in marine shales from the Ordovician to the Tertiary, with morphologically closely related forms appearing in the Cambrian. Its simple morphology together with its long stratigraphic range and abundance makes it attractive as a potential thermal maturity indicator. The colour of Veryhachium is characterised in terms of red, green and blue intensity of transmitted white light. With increasing thermal maturity, Veryhachium changes from almost colourless to black, with the most rapid change taking place in rocks that are marginally postmature with respect to the oil window. The cutoff point for Veryhachium fluorescence lies between 1.5% and 2.0% in terms of vitrinite reflectance (Rr), providing another useful tie-point in terms of thermal maturity. This technique is simple, inexpensive and has potential for establishing the thermal maturity of both marine Lower Palaeozoic rocks and younger marine sections deficient in vitrinite.
Possible seismic hydrocarbon indicators in offshore Cyprus and Lebanon
Authors: Semb Per Helge 
Published: October 2021

ABSTRACT
A multi-client 2-D seismic survey, consisting of 6,770 line-kilometer of 2-D data, was acquired by Norway’s PGS Geophysical offshore Cyprus in 2006. It was followed in 2006 and 2007 by the acquisition of two 3-D surveys, located offshore Lebanon (1,500 square kilometers), and offshore Lebanon and Cyprus (1,300 square kilometers). Further, in 2008 an additional 2-D survey was acquired offshore Cyprus to fill in the existing 2006 seismic 2-D grid. The 2008 2-D survey consist of 6,500 line-kilometer and was acquired with the PGS dual sensor GeoStreamer® technology (The 2008 2D data is still being processed so no GeoStreamer® examples are shown in this article). Since 2007, some of the deep-water areas (1,500–2,000 meters deep) offshore Cyprus have been offered for exploration and producing bid licenses by the government, while the Lebanese government is in the stage of preparing its offshore region for exploration and licensing.
In this paper, several representative seismic lines are shown to illustrate the quality of the seismic data over this large region. The data shows that a Pliocene to Recent succession overlies a thick Upper Miocene evaporite section, known as the Messinian Salt. The blanketing salt-dominated interval is up to one kilometer thick and provides a regional seal over the area; although some faults are known to penetrate the salt and may allow seepage to occur. The pre-Messinian Salt section is highly structured, with both horsts-and-grabens as well as large folds. In particular, several examples of seismic reflections are presented, which are interpreted as possible Direct Hydrocarbon Indicators (DHI). Some four-way structural closures are highly prospective as they are characterized by multiple DHIs; for example, a bright spot at the base of the Messinian Salt overlying a flat spot. Other examples consist of phase changes, dim spots, velocity pull-downs, low-frequency shadow zones and gas chimneys. Also shown are how some of these interpreted DHIs can be characterized in the 3-D surveys. The 3-D example illustrate a correlation between pre-Messinian four-way structural closure and the root-mean square amplitude of the base Messinian Salt reflection.