bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exploration for a Frontier Salt Basin in Southwest Oman
Authors: Blood Mark F. 
Published: October 2021

ABSTRACT
An undrilled Infracambrian-lower Paleozoic salt basin is interpreted as being present in the Dhofar area of southwest Oman. A re-evaluation of the existing seismic and gravity data indicated that the basin is located immediately north of a major NE-orientated basement feature known as the Ghudun-Khasfah High. The basin is centered in the southern part of the Al Hashman Block 36 and the northern part of Mudayy Block 38, both operated by Phillips. Studies conducted by Phillips suggest that the basin has a similar structural history and pre-Silurian stratigraphy to the known salt basins of Oman. New stratigraphically deeper Paleozoic and Infracambrian exploration plays that are proven in the other Oman salt basins are proposed for this undrilled basin. The new plays rely on an unproven Infracambrian Huqf source. Source and reservoir degradation through widespread post-Huqf deformation is possible, but structural modeling and seismic facies analysis, together with the detection of significant micro-seepage anomalies, suggest otherwise. In addition, the identification and gravity modeling of what appear to be salt features on seismic lines support the presence of Lower Cambrian salt swells and piercement structures. The salt features are believed to be age equivalent to the Ara salt section of the upper Huqf Supergroup present in the other salt basins. Phillips has named this potential salt basin the Ghudun Salt Basin.
Upper Burgan Reservoir Description, Northern Kuwait: Impact on Reservoir Development
Authors: Al-Eidan Ahmad J. , Wethington W. Barry , Davies Roger B. 
Published: October 2021

ABSTRACT
The giant Albian upper Burgan reservoir in northern Kuwait is a major productive interval in both the Raudhatain and Sabiriyah fields. It is planned to increase production from the upper Burgan by over 300 percent through the application of field-wide waterflood. Phase 1 of seawater injection was started in 1999. A comprehensive geological study of the upper Burgan has included reviews of all core data, biostratigraphic information, and geochemical and petrographic analyses. The results indicate that the reservoir sandstones were laid down in a complex series of paralic environments ranging from shallow-marine to valley-fill channels. The resultant layering scheme was integrated with all available dynamic data to best define the reservoir architecture and flow units, and to construct a fine-grid 3-D geological model. The geological analysis has had a significant impact on reservoir development, influencing waterflood strategy, pattern orientation and expected performance. In the Raudhatain field, where reservoir connectivity is relatively high, a peripheral waterflood will be implemented (at least initially), whereas the complex structure and stratigraphy of the Sabiriyah field dictate a pattern flood.
Qasim Formation: Ordovician Storm- and Tide-Dominated Shallow-Marine Siliciclastic Sequences, Central Saudi Arabia
Authors: Senalp Muhittin , Al-Duaiji Abdulaziz A. 
Published: October 2021

ABSTRACT
The Middle to Upper Ordovician Qasim Formation is well exposed in the Qasim region of central Saudi Arabia and is recognized from many wells to the north and east. It consists of the Hanadir, Kahfah, Ra’an, and Quwarah members that are arranged in two coarsening-upward progradational sequences that have a total thickness of about 200 m in outcrops. Two sections were measured in each sequence.
The lower sequence is a storm-dominated, shallow-marine depositional system composed of the late Llanvirn to middle Caradoc Hanadir and Kahfah. At least five progradational beach parasequences were identified. The Hanadir overlies deltaic deposits of the upper Saq Formation and marks a major marine transgression onto Gondwana. It is composed of laminated fissile shale formed in an offshore marine environment together with siltstone laminae that indicate periodic influxes of low-density turbidity currents. The overlying Kahfah is composed of shale and sandstone.
The upper progradational sequence consists of the middle Caradoc to middle Ashgill Ra’an and Quwarah members. The Ra’an is a succession of homogeneous fissile shale and minor siltstone laminae formed in an offshore marine environment following a major transgression onto the Kahfah. The overlying Quwarah consists of sandstone and minor amounts of siltstone and shale in its lower parts, and a thickly bedded sandstone facies above. The diagnostic sedimentary structures in the Quwarah are large-scale lens-shaped tidal sand waves composed of sigmoidal bundles deposited in a mesotidal setting of barrier bars, tidal channels, ebb-dominated deltas and lagoons.
In the subsurface, the Formation thickens northeastward (basinward) to over 4,000 ft (1,220 m). In the same direction, the sand-dominated Kahfah and Quwarah gradually become shale-dominated, small-scale bed forms are more abundant, and identification of members based on lithofacies is more difficult.
After deposition of the Quwarah, present-day Saudi Arabia was affected by a Late Ordovician (late Ashgill) glaciation. The Qasim and older formations are deeply incised by glacial channels at the base of the Zarqa and Sarah formations. Basinward, the glacial unconformities (or their submarine erosion surface equivalents) become less significant and a thick succession of the Formation is preserved.
Tectonic Evolution of the Eastern Mediterranean Basin and its Significance for the Hydrocarbon Prospectivity of the Nile Delta Deepwater Area
Authors: Ahmed AbdelAal , Ahmed El Barkooky , Marc Gerrits , Hans-Jürg Meyer , Marcus Schwander , Hala Zaki 
Published: October 2021

ABSTRACT
The deepwater area of the Nile Delta is within the eastern Mediterranean basin on the Nile Delta Cone between the Herodotus abyssal plain to the west and the Levant basin to the east. The complex evolution and interaction of the African, Eurasian and Arabian plates have shaped the Late Miocene to Recent Nile Cone and its substratum. The tectono-stratigraphic framework is controlled by deep-seated basement structures with distinct gravity and magnetic expressions, and by the interaction of the NW-trending Misfaq-Bardawil (Temsah) and NE-trending Qattara-Eratosthenes (Rosetta) fault zones. In addition, significant salt-induced deformation of a Messinian evaporitic sequence up to 4,000 m thick has occurred, together with large-scale rotational block movement. The deformational pattern is largely the result of multiphase tectonic movements along pre-existing basement faults on the continental margin of the Neo-Tethys ocean.
The Nile Cone consists of late Paleogene to Late Miocene sediments that pre-date the Messinian evaporites, and Pliocene-Pleistocene sequences. In the east, the pre-salt deposits (as much as 3,000 m thick) are primarily deepwater sediments with local condensed sequences over syndepositional intrabasinal highs. Shale occurs westward across the Rosetta trend. The Messinian evaporitic sequence exhibits three distinct seismic facies suggesting cyclic deposition with the occurrence of interbedded anhydrite, salt and clastic sequences and pure halite deposition. During the Messinian salinity crisis, large-scale canyons were excavated that resulted in multiphase cut-and-fill clastic systems. The Pliocene-Pleistocene sequences were deposited in a slope to basin-floor setting.
Exploration targets are the Pliocene-Pleistocene deepwater channel and basin-floor turbidite sands in a variety of structural settings. Water depths range from 800 to 2,800 m. The Upper Miocene sequence offers additional exploration objectives in the form of fluvial and/or turbidite sands. The focus of pre-salt exploration is the delineation of distal turbidities within the Serravallian to Tortonian sequence and the identification of new reservoir sequences deposited on pre-existing intrabasinal highs. Hydrocarbon charge has yet to be proven by drilling, but seismic amplitude anomalies and the occurrence of natural surface slicks suggest both gas and liquid charges from pre-salt source rocks through faults and salt-withdrawal windows.
Impact of 3-D Seismic Surveys on Development of the Minagish Oolite Reservoirs, Minagish and Umm Gudair Fields, Kuwait
Authors: Al-Ateeqi Alaa M. , Foster Dave G. 
Published: October 2021

ABSTRACT
The Kuwait Oil Company acquired 2-D and 3-D seismic data from 1996 to 1998 in a program that is believed to be one of the largest undertaken in the region. The 2-D surveys were used to define possible prospective areas, whereas the 3-D surveys have helped to increase the productivity of the existing oil fields. The 3-D surveys acquired over the Minagish and Umm Gudair fields in onshore West Kuwait were two of the first to be completed. The data is of excellent quality with high signal-to-noise ratios and stable phase and amplitude characteristics. The rapid 3-D interpretation was made possible by using state-of-the-art interpretation and visualization software, and has already had a considerable impact on the perception of the subsurface geology of the mainly Cretaceous reservoirs. In both fields, fault patterns were reliably defined for the first time and accurate depth maps resulted from careful attention to the near-surface static corrections, depth conversions and interpretations made from the superior 3-D imaging. These factors have enabled the accurate placement of wells. Acoustic impedance data is being used to define reservoir and aquifer porosity distribution. The impact of the 3-D surveys has enabled optimum development decisions to be made, thus helping to maximize Kuwait’s valuable oil resources.
Stratigraphy, micropaleontology, and paleoecology of the Miocene Dam Formation, Qatar
Authors: Al-Saad Hamad , Ibrahim Mohamed I. 
Published: October 2021

ABSTRACT
The Miocene carbonate Dam Formation is well exposed in the Jebel Al-Nakhash area of southern Qatar. Three sections were measured in a detailed investigation of the Formation’s stratigraphy, micropaleontology, and paleoecology. This biostratigraphic and paleoecologic study was supported by the analysis of microlithofacies and foraminiferal assemblages. Microfossils are predominantly benthic foraminifera represented by 38 species, many of which are milioline and one is a larger form. A Borelis melo melo Local Range Zone of Early Miocene (Burdigalian) age was recognized. The nature and distribution of the benthic foraminiferal assemblage, in association with lithofacies evidence, indicated a general shoaling-upward trend.
The Dam Formation was stratigraphically subdivided into two new formal members. The basal Al-Kharrara Member is made up of limestone, marl, and claystone, and the overlying Al-Nakhash Member is a cyclic assemblage of carbonate, evaporite, and algal stromatolite facies. The lithofacies are grouped into four major types of which limestone, subdivided into six subfacies, is dominant. The Al-Kharrara was interpreted as having been deposited in warm (25°–30°C), clear, shallow waters of the inner neritic zone (0–35 m) that had an elevated salinity (35‰–50‰) and a vegetated substrate. The Al-Nakhash probably formed in an oscillating, very shallow-marine environment (0–10 m deep, including tidal flats), under warm climatic conditions that eventually led to the accumulation of evaporites and algal stromatolites.
Quaternary Development of the United Arab Emirates Coast: New Evidence from Marawah Island, Abu Dhabi
Authors: Evans Graham , Kirkham Anthony , Carter Robert A. 
Published: October 2021

ABSTRACT
Marawah is one of a chain of barrier islands off the coast of Abu Dhabi that separates the Khor Al Bazm lagoon from the open waters of the Arabian Gulf. The island consists of several rocky cores of Pleistocene limestone linked by areas of unconsolidated Holocene carbonates. It has the most complete Quaternary outcrop sequence in the region and the lowest exposed unit, a coralline limestone, had not been recorded previously. The Pleistocene deposits accumulated partly in a shallow-marine environment and partly under eolian conditions. The Marawah sections have revealed new data about the history of the southern Gulf in the late Pleistocene, a time interval of which little was known. The survey has shown that there were periods when sea level was close to present-day levels and other times when it was approximately 4 to 5 m higher than today. A phase of deflation and the development of a field of eolian sand dunes separated these two sea-level highstands. The unconsolidated sediments have accumulated around the Pleistocene rock cores since about 4,500 years BP to give the island its present form. Accumulation occurred because of wave action driven by the northwesterly ‘Shamal’ winds during periods of slightly falling or almost stationary sea level.
Chronostratigraphy, palynofacies, source-rock potential, and organic thermal maturity of Jurassic rocks from Qatar
Authors: Ibrahim Mohamed I. A. , Al-Saad Hamad , Kholeif Suzan E. 
Published: October 2021

ABSTRACT
Strontium isotope, palynological, and total organic carbon (TOC) analyses were made on core samples from the Izhara, Araej, and Hanifa formations of three wells in onshore Qatar. Eleven samples were analyzed for their 87Sr/86Sr ratios. The results gave a chronostratigraphic range of Early Jurassic (Hettangian) to Late Jurassic (Oxfordian), with an overall age range of 202.4 Ma to 157.8 Ma. Maximum flooding surfaces MFS J10 to MFS J50 occur in the Izhara, Araej, and Hanifa formations.
The organic matter in the carbonate sediments of the Izhara, Araej, and Hanifa formations was almost exclusively of marine algal origin dominated by marine microplankton. Organic matter obtained from the Izhara Formation was mature to over-mature kerogen type-III to IV, gas-prone to inert material (mean TOC 0.31%). In the Araej Formation, mature oil-prone and gas-prone kerogen type-II and type-III organic matter occurred in both the lower and upper Araej members (TOC 0.13-0.69%). The stylolitic limestone of the Uwainat member of the Araej Formation has poor potential as a source rock for petroleum (TOC 0.03-0.13%), but is considered to be the main reservoir rock of the Middle Jurassic in Qatar. Mature, highly oil-prone organic matter (type-I and type-II kerogen) was present in black limestone of the Hanifa Formation (mean TOC 0.60%; maximum 0.93%). The limestone is considered to be the most likely petroleum source rock for the underlying and overlying limestone reservoirs of the Uwainat member of the Araej Formation (Bathonian) and the Arab-D member of the Arab Formation (Kimmeridgian) units, respectively.
Paleoecological and paleobiogeographical significance of the rudist Macgillavryia chubbii sp. n. in the Campanian of Oman
Authors: Philip Jean M. 
Published: October 2021

ABSTRACT
Excellently preserved specimens of the large rudist Macgillavryia have been described for the first time from the Campanian Samhan Formation in the vicinity of Filim and Hayy on the eastern side of the Haushi-Huqf massif in Oman. A new species, M. chubbii, was named and found to be equivalent to other species of Macgillavryia from the Caribbean domain. The exceptionally well-preserved holotype with its articulated valves allowed the reconstruction of the functional morphology of the mantle. The indications are that the left valve of M. chubbii covered only a small part of the commissural area, leaving a large part of the mantle of the right valve directly exposed to sea water and sunlight. As a result, M. chubbii has been proposed as a potential candidate for an association with zooxanthellae. Macgillavryia is a typical epifaunal rudist that probably lived in very shallow, clear seas. The shell was not buried during its lifetime but was exposed to epibionts and bioeroders. The excellent exposures allowed the reconstruction of relationships between Macgillavryia and other biotic or abiotic components. They formed a densely packed association with spaces filled by a very coarse bioclastic material. The superpositioning of two or more layers with superstratal growth fabrics created individual rudist banks more than 1 m thick covering several hundred square meters. Paleobiogeographic reconstructions have connected M. chubbii in Arabia with Macgillavryia in the Caribbean by eastward dispersion through the Pacific region.
Reservoir rock classification, Arab-D reservoir, Ghawar field, Saudi Arabia
Authors: Cantrell Dave L. , Hagerty Royal M. 
Published: October 2021

ABSTRACT
An integrated petrographic and petrophysical study of Arab-D carbonates in Ghawar field has provided a new reservoir rock classification. This classification provides a simple but practical method of dividing the complex carbonate rocks of the Arab-D into meaningful reservoir rock types. Each rock type has a distinct pore network as defined by porosity-permeability relationships and capillarity expressed as pore-size distributions and J-function curves. The classification divides the Arab-D carbonates into seven limestone and four dolomite rock types. The amount of matrix (lime mud) and the pore types are the primary controlling parameters for the limestones. The dolomites are divided according to their crystal texture.
The seven limestone reservoir rock types are based on the values of five petrographic parameters: (1) the amount of cement, (2) the amount of matrix (lime mud), (3) the grain sorting, (4) the dominant pore type, and (5) the size of the largest molds. The amount of matrix is the most important of these five parameters. In general terms, six of these seven types fall into two broad families, A and B, each of which can then be subdivided into three members (Types I, II, and III) according to their matrix content. The first family, A, is a fairly coarse-grained, poorly sorted rock with relatively large molds. The second family, B, is a generally fine to medium-grained, well sorted rock with few or small molds. The seventh rock type contains more than 10 percent cement which modifies the pore size distribution enough to warrant a separate reservoir rock type. Each of the reservoir rock types exhibits a distinctive pore-size distribution and, in turn, Leverett J-function or capillarity. The seven types are also characterized by distinctive porosity-permeability relationships.
The four dolomite reservoir rock types are classified according to their dolomite crystal texture, although stratigraphic position and porosity can also be effective in their classification. The four textures are: fabric preserving (Vfp), sucrosic (Vs), intermediate (Vi) and mosaic (Vm). The Vfp dolomite is only found in Zone 1 of the Arab-D where it is the major dolomite type. Vs dolomite occurs in dolomites with more than 12 percent porosity, Vm less than 5 percent and Vi between 5 and 12 percent. Vfp dolomites have pore systems similar to their precursor limestone but the pore systems of the other dolomite types are unique.
A significant finding of this evaluation is that the micropore system in all major limestone rock types in Zones 1 and 2 (upper Arab-D) is consistently an order of magnitude larger than for the same rock types in Zones 3 and 4 (lower Arab-D). The increase in size is believed to be a result of increased leaching in the upper Arab-D. This difference suggests that rocks of similar type from the upper and lower Arab-D will behave differently in terms of their fluid flow and saturation characteristics, and will have different ultimate recoveries.
The Sahmah Formation of Oman: exploration implications for the Rub’ Al-Khali Basin
Authors: Svendsen Nick B. 
Published: October 2021

ABSTRACT
The Sahmah Formation (Safiq Group, Haima Supergroup) of Oman is divided into a lower ‘Shale Member’ (or ‘Sahmah Shale’), and an upper ‘Sandy Member’. The Shale Member was deposited in a deep-marine environment, and the Sandy Member in a marginal marine setting. The formation is greater than 500 meters thick in the Burkanah-1 exploration well, located in south Oman along the eastern edge of the Rub’ Al-Khali Basin. In many areas in Oman, the formation is absent due to erosion by the ‘Hercynian’ unconformity. The age of the Sahmah is generally interpreted as Early Silurian Llandovery; however, recent biostratigraphic studies suggest that it may range in age from latest Ordovician Ashgill to Llandovery. The basal Sahmah Shale (3–10 meters thick) is an excellent source rock, as confirmed by its correlation to the ‘B’ oil in the overlying Permian Gharif Formation in the Sahmah field in central Interior Oman.
This study combined new and previously acquired geological data from 16 wells in Oman, and includes source rock analytical data. A basin model was used to assess the maturation history of the Sahmah Shale, and the hydrocarbon potential of two associated petroleum systems. The first system occurs along the ‘Hercynian’ erosional edge of the Sahmah source rock. The migration pathway involves vertical charging of the overlying Upper Carboniferous-Lower Permian Al Khlata Formation or/and the Permian Gharif Formation. This area constitutes the Sahmah Shale:Gharif Formation(!) Petroleum System. The second Petroleum System, the Sahmah Shale:Hasirah Formation(?), applies to regions where the Sahmah is thick, and intra-Sahmah shales act as a seal. In these regions, if the shale is mature and the pre-Sahmah section is porous, then down charging provides the migration pathway to the trap.