bluuebunny/crossref_metadata_2025 huggingface dataset:
Sağlıkta Dönüşüm Sonrası Sağlık Harcamaları ve Sağlık Enflasyonu: Zaman Serisi Analizleri
Authors: ANKARA Hasan Giray , ZEYBEK Dolunay Özlem
Published: October 2021

Bu çalışma Sağlıkta Dönüşüm Programı (SDP) sonrası süreçte sağlık harcamalarının ve sağlık enflasyonunun seyrinde rol oynayan bileşenlerle sağlık enflasyonunun genel enflasyon üzerindeki etkilerini incelemektedir. Çalışma kapsamında ikincil veriler kullanılmıştır. Analizlerde Türkiye İstatistik Kurumu (TÜİK) ve Türkiye Cumhuriyet Merkez Bankası (TCMB) tarafından raporlanan sağlık harcamaları, genel enflasyon ve sağlık enflasyonu verileri kullanılmıştır. Genel enflasyon ve sağlık enflasyonu verileri TCMB raporlarından, sağlık harcamaları verileriyse sağlık istatistikleri yıllıklarından temin edilmiştir. Çalışmanın konusunun SDP sonrası dönemi kapsaması dolayısıyla çalışma kapsamındaki sağlık harcamaları analizleri 2003-2017 yılları arası veriler kullanılarak sağlık enflasyonu analizleri ise 2005-2017 yılları arası veriler kullanılarak gerçekleştirilmiştir. Çalışma kapsamında araştırılan kısa ve uzun dönemli etkiler zaman serisi analizleriyle ortaya konulmuştur. Analizler sonucunda SDP sonrası toplam sağlık harcamalarındaki artışın en önemli bileşeninin kamu sağlık harcamalarındaki artışlar olduğu anlaşılmıştır. SDP kapsamında kurulan SGK (Sosyal Güvenlik Kurumu), harcamalarındaki artışın kamu sağlık harcamalarının artışına neden olduğu ve özel sağlık harcamalarındaki artışlara hane halkı harcamalarındaki artışların önemli ölçüde etki ettiği görülmüştür. Sağlık enflasyonunun zaman içerisindeki seyrinin en önemli bileşeninin tıbbi ürünlerde ve ayakta tedavi hizmetlerinde yaşanan fiyat artışları olduğu anlaşılmıştır. Ayrıca sağlık enflasyonundaki artışların genel enflasyon üzerinde istatistiksel olarak anlamlı etkiye sahip olduğu ve beklenmedik bir şekilde, uzun dönemde genel enflasyonu az da olsa azaltıcı rol oynadığı görülmüştür.
Compras Públicas no Brasil: vertentes de inovação, avanços e dificuldades no período recente
Authors: Fernandes Ciro Campos Christo
Published: October 2021

Este artigo é um balanço dos avanços, limitações e perspectivas para o fortalecimento das compras públicas na administração pública brasileira. A pesquisa se baseou no levantamento, categorização e análise de trabalhos sobre temas de compras públicas. A pesquisa focalizou a produção científica apresentada nos congressos anuais da administração pública, entre 2008 e 2016, promovidos pela associação que congrega os líderes responsáveis pela gestão pública dos Estados brasileiros. Uma amostra de trabalhos que tratam especificamente de compras públicas foi selecionada. Apresenta-se uma visão sistemática das principais mudanças e inovações, destacando as seguintes tendências: marco legal e regulatório, sistemas informatizados e portais na internet, reestruturação dos formatos de compra e contratação, terceirização, metodologias e ferramentas de gestão das compras, uso do poder de compra, ciclo do suprimento, centralização das compras e institucionalização da área.
Paleozoic (Pre-Khuff Hydrocarbon Geology of the Ghawar Area, Eastern Saudi Arabia
Authors: Wender Lawrence E. , Bryant Jeffrey W. , Dickens Martin F. , Neville Allen S. , Al-Moqbel Abdulrahman M.
Published: October 2021

Saudi Aramco is conducting an exploration program to discover additional non-associated gas reserves in the Ghawar Area. The program has successfully discovered significant sweet gas and condensate reserves in the pre-Khuff siliciclastics and has further increased our understanding of the Paleozoic petroleum system.

The Lower Permian Unayzah Formation is the principal pre-Khuff hydrocarbon reservoir in the Southern Ghawar Area, where it contains both oil and gas. The Unayzah consists of fluvial to marginal marine sandstones. The Devonian Jauf Formation is the principal pre-Khuff reservoir in the Northern Ghawar Area, where it hosts the recently discovered giant Hawiyah gas-condensate field. The Jauf consists of shallow marine sandstones that exhibit unusually high porosities considering the burial depths. The primary source rock for pre-Khuff hydrocarbons is the basal “hot shale” of the Lower Silurian Qalibah Formation. Maturation modeling of these shales indicates hydrocarbon generation began in the Middle Triassic (oil) and continues to the present (dry gas).

Pre-Khuff hydrocarbon traps are found in simple four-way closures as well as more complex structural-stratigraphic traps on the flanks of Hercynian structures. Trap formation and modification occurred in four main phases: (1) Carboniferous (Hercynian Orogeny); (2) Early Triassic (Zagros Rifting); (3) Late Cretaceous (First or Early Alpine Orogeny); and (4) Tertiary (Second or Late Alpine Orogeny). Structures in the Ghawar Area show differences in growth histories, which have impacted the amount and type of hydrocarbons contained.
Paleozoic Petroleum System of Central Saudi Arabia
Authors: Abu-Ali Mahdi A. , Rudkiewicz Jean-Luc L. , McGillivray Jim G. , Behar Françoise
Published: October 2021

An integrated geochemical model was developed to reconstruct the history of expulsion, migration and entrapment of Paleozoic oil and gas in the main regional Permian Unayzah Sandstone Reservoir in Central Saudi Arabia. The model indicates that by the Late Jurassic, approximately 140 million years ago (Ma), the principal Paleozoic source rock, the Lower Silurian Qusaiba “hot” shale, was mature in the deepest hydrocarbon “kitchens”. Hydrocarbon expulsion started during the Aptian and Albian (late Early to early Middle Cretaceous, 100 to 120 Ma).

Expulsion of oil and gas is linked to three geochemical events. Primary kerogen cracking led to a first episode of expulsion about 120 Ma. Secondary heavy component and oil cracking resulted in a second episode of expulsion at approximately 100 Ma. Between 20 to 10 Ma, later uplift, and the resulting pressure drop in the source rock, led to a third expulsion phase. The first two expulsion episodes were gradual, whereas the third was more rapid and related to uplift of the Arabian Arch, opening of the Red Sea and the Zagros Orogeny during the Miocene. Expulsion of oil nearly terminated after the Late Cretaceous, while gas continued to be expelled, though at a lower rate, in the Tertiary. Peak gas expulsion occurred post Early Eocene with significant gas generation from secondary cracking of oil retained in the source rock.

Gas was sourced either directly from kerogen, or from secondary cracking of heavy absorbed components or non-migrated oils. The expulsion of gas coincides with oil expulsion for the first two episodes because the gas and oil formed as a single phase. As a result of Tertiary Uplift, gas separated from the oil and re-migrated in the final episode (20 to 10 Ma).
Geology and Production Significance of Dolomite, Arab-D Reservoir, Ghawar Field, Saudi Arabia
Authors: Cantrell David L. , Swart Peter K. , Handford Robertson C. , Kendall Christopher G. , Westphal Hildegard
Published: October 2021

At least five distinct types of dolomite occur in the Arab-D Reservoir in Ghawar field, Saudi Arabia – one of which appears to be responsible for high flow or ‘super-k’. These dolomite types are distinct petrographically, geochemically and stratigraphically: a finely-crystalline non-fabric-preserving (NFP) variety of dolomite in the lower Arab-D (Zone 3) with low oxygen isotope values and generally poor reservoir quality;a medium-crystalline NFP dolomite with high oxygen isotope values and very poor reservoir quality in the upper Arab-D (Zone 2);a medium to coarsely-crystalline NFP dolomite with low oxygen isotopic values and very good reservoir quality (‘super-k’) occurring in Zone 2; anda finely-crystalline fabric-preserving (FP) dolomite in the uppermost Arab-D (Zone 1) that contains high oxygen isotope values and has generally fair to poor reservoir quality.

Previous studies have documented a rare fifth type of dolomite, baroque or ‘saddle’ dolomite, that occurs locally in the reservoir as well.

This study also quantified and mapped the abundance and distribution of dolomite across the field, using all available core and log data. Analysis of dolomite distribution map patterns reveals that dolomite occurs in Ghawar as a series of linear trends extending for tens’s of kilometers. These map pattern trends are best-developed in Zone 2B, but are also visible in Zones 2A and 3A as well. Baroque dolomite appears to be limited to a few areas of vertically pervasive dolomite occurring on the same trends of high dolomite content. The linearity of these dolomite trends strongly suggests that some structural element is responsible for controlling their orientation. We interpret these linear patterns to have formed in response to a series of fracturing and/or faulting events that allowed dolomitizing fluids to move up into the reservoir from below, and preferentially dolomitize there.

Both a qualitative and a quantitative analysis of performance data (flowmeters) in southern Ghawar (Haradh) indicate that these trends of high dolomite have a profound influence on fluid flow in the reservoir. A qualitative analysis of occurrences of ‘super-k’ in the Arab-D in Haradh suggests that most ‘super-k’ zones (seen as ‘spikes’ or step profiles on the flowmeter) occur in the high dolomite trend in Haradh. A quantitative analysis of flowmeter data and a comparison of this analysis with dolomite map patterns indicate that most reservoir flow occurs where dolomite is abundant, and suggests that there is a direct relationship between patterns of high flow and high dolomite.
Egypt in the Twenty-First Century: Petroleum Potential in Offshore Trends
Authors: Dolson John C. , Shann Mark V. , Matbouly Sayed I. , Hammouda Hussein , Rashed Rashed M.
Published: October 2021

Since the onshore discovery of oil in the Eastern Desert in 1886, the petroleum industry in Egypt has accumulated reserves of more than 15.5 billion barrels of oil equivalent. An understanding of the tectono-stratigraphic history of each major basin, combined with drilling history and field-size distributions, justifies the realization of the complete replacement of these reserves in the coming decades. Most of the increase in reserves will be the result of offshore exploration.

In addition to the 25 trillion cubic feet already discovered, the offshore Mediterranean may hold 64 to 84 trillion cubic feet and the onshore Western Desert may contribute 15 to 30 trillion cubic feet in new gas resources. Many of the new fields are expected to be in the giant-field class that contains greater than 100 million barrels of oil equivalent. Challenges include sub-salt imaging, market constraints for predominantly gas resources and economic constraints imposed by the high cost of development of the current deep-water gas discoveries that are probably unique worldwide. The offshore Gulf of Suez may yield an additional 1.5 to 3.3 billion barrels of oil equivalent, but it continues to be technologically constrained by poor-quality seismic data. Advances in multiple suppression and development of new ‘off-structure’ play concepts with higher quality seismic data should result in continual new pool discoveries. Offshore frontier exploration includes the Red Sea rift (currently under reassessment with area-wide 3-D surveys) and the Gulf of Aqaba. Deep-water and sub-salt imaging remain significant challenges to be overcome.

Despite a relatively complex history, the Phanerozoic geological framework of Egypt is extremely prospective for oil and gas. Eight major tectono-stratigraphic events are: (1) Paleozoic craton; (2) Jurassic rifting; (3) Cretaceous passive margin; (4) Cretaceous Syrian Arc deformation and foreland transgressions; (5) Oligocene-Miocene Gulf of Suez rifting; (6) Miocene Red Sea opening; (7) the Messinian salinity crisis; and (8) Pliocene-Pleistocene delta progradation. Each of these events has created multiple reservoir and seal combinations. Source rocks occur from the Paleozoic through to the Pliocene and petroleum is produced from reservoirs that range in age from Precambrian to Pleistocene. The offshore Mediterranean, Gulf of Suez and Red Sea/Gulf of Aqaba contain significant exploration potential and will provide substantial reserve replacements in the coming decades.
Paleozoic Stratigraphy and Hydrocarbon Habitat of the Arabian Plate
Authors: Geert Konert , Afifi Abdulkader M. , Al-Hajri Sa’id A. , Droste Henk J.
Published: October 2021

The Paleozoic section became prospective during the early 1970s when the enormous gas reserves in the Permian Khuff reservoirs were delineated in the Gulf and Zagros regions, and oil was discovered in Oman. Since then, frontier exploration has targeted the Paleozoic System throughout the Middle East, driven by various economic considerations. The Paleozoic sequences were essentially deposited in continental to deep marine clastic environments at the Gondwana continental margin. Carbonates only became dominant in the Late Permian. The sediments were deposited in arid to glacial settings, reflecting the drift of the region from equatorial to high southern latitudes and back. Following late Precambrian rifting that formed salt basins in Oman and the Arabian Gulf region, the Cambrian-Devonian sequences were deposited on a peneplained continental platform. The entire region was affected by the Hercynian Orogeny, which climaxed during the Carboniferous. The orogeny manifested itself in a change in basin geometry, inversion tectonics, regional uplift and tectonism along the Zagros fault zone. This deformation caused widespread erosion of the Devonian-Carboniferous and older sections, and was probably caused by collision along the northern margin of Gondwana. The Paleozoic tectonic super cycle ended with the onset of break-up tectonics in the Permian, and the deposition of Khuff carbonates over the newly formed eastern passive margin. A major Paleozoic petroleum system embraces reservoir seal pairs spanning the Silurian to Permian sequences. Hydrocarbons occur in a variety of traps, and are sourced by the Silurian ‘hot shale’. A second petroleum system occurs in areas charged from upper Precambrian source rocks in the salt basins. Hydrocarbon expulsion estimates, taking into account secondary migration losses, suggest that some one trillion barrels of oil equivalent (BOE) may have been trapped from the Silurian ‘hot shale’ alone. However, the long and complex hydrocarbon geological evolution of the basin, combined with low acoustic contrasts between target rock units, difficult surface conditions, tight reservoirs, and deep subsurface environments, posed significant challenges to exploration and development. The critical success factor is the continuous innovative effort of earth scientists and subsurface engineers to find integrated technology solutions, that will render the Paleozoic plays economically viable.
Exploration Strategy Development and Performance Management: a Portfolio-based Approach
Authors: Naylor Michael A. , Spring Laurent Y.
Published: October 2021

In Petroleum Development Oman (PDO), the exploration opportunity portfolio is managed by a dedicated team responsible for its integrity and analysis. The team uses a customized suite of tools for volumetric and economic assessment that has been developed since 1997. In addition to their application in quality control, regular performance monitoring and reporting, the tools are used to determine annual finding targets and formulate exploration strategies.

The portfolio management process in PDO has made a major contribution to the quality of prospects that are selected for drilling. Thanks to new evaluation processes and a robust suite of tools, the company has a better understanding of the composition and quality of the prospect portfolio, and is explicitly aware of the challenges and issues facing exploration. Portfolio management tools enable objective target setting and communication, thereby achieving shared ownership. The clarity brought by portfolio analyses provides a powerful focus to the asset teams’ efforts to improve prospect quality.

PDO is also able to quantify the consequences of changing activity levels and balance in the program, and of the limitations imposed by the portfolio. These provide the basis for ongoing dialogue with shareholders and justify the strategy shift towards frontier exploration enacted since 1998. Exploration in PDO has shifted from being opportunity-driven to being led by a portfolio-based strategy. A similar approach may be suited to other exploration ventures with sizeable portfolios.
Sequence stratigraphy of Oxfordian and Kimmeridgian shelf carbonate reservoirs, offshore Abu Dhabi
Authors: Al-Suwaidi Ahmed S. , Aziz Sabah K.
Published: October 2021

Carbonate reservoirs on the eastern flank of the Oxfordian-Kimmeridgian intrashelf basin in offshore Abu Dhabi had received little attention until commercial oil accumulations in structural traps were discovered in the late 1980s and early 1990s. In order to clarify the geometric and chronostratigraphic relationships of the Oxfordian-Kimmeridgian reservoirs, a multidisciplinary study (seismic, lithobiofacies, geochemistry, strontium isotope dating, and well-log data) was used to develop a sequence stratigraphic model.

After deposition of the Callovian upper Araej Formation, a differentiated carbonate platform was established in the early Oxfordian in offshore and western onshore Abu Dhabi. Tectonic subsidence coupled with sea-level fluctuations controlled the geometry, deposition, and distribution of the lithofacies. These ranged from organic-rich, limy mudstones in the basinal area, to porous and permeable bioclastic packstones, grainstones, and dolomites in shallow waters on the eastern flank of the intrashelf basin. The upper Kimmeridgian Arab-D Member of the Arab Formation overlies the basinal deposits.

Three third-order Depositional Sequences were identified in the offshore area. They are named according to their contained Maximum Flooding Surface; a fourth sequence is an intermediate unnamed Depositional Wedge. Depositional Sequence Jurassic 50 is of Oxfordian age and was deposited during transgressive and highstand periods. The lower Kimmeridgian Depositional Sequence Jurassic 60 is a well-defined lowstand system tract overlain by short-lived transgressive and highstand system tracts. Overlying Depositional Sequence Jurassic 60 is the Depositional Wedge. Finally, Depositional Sequence Jurassic 70 consists of transgressive and highstand system tracts developed on an undifferentiated platform that had localized depressions in the west. The best reservoir developments are in highstand bioclastic packstones and grainstones below the type-1 sequence boundaries that cap Depositional Sequences Jurassic 50 and Jurassic 60. The reservoir units have porosities greater than 20 percent and permeabilities of more than 1,000 milliDarcies. The basinal facies of Depositional Sequence Jurassic 50 have the best source-rock potential in the intrashelf basin.
Sequence stratigraphy, biostratigraphy and paleontology of the Maastrichtian-Paleocene Aruma Formation in outcrop in Saudi Arabia
Authors: Philip Jean M. , Roger Jack , Vaslet Denis , Cecca Fabrizio , Gardin Silvia , Memesh Abdullah M.S.
Published: October 2021

The Aruma Formation is a predominantly carbonate lithostratigraphic unit of Late Cretaceous age that crops out in Saudi Arabia. It consists of three members: from base to top they are Khanasir Limestone Member, Hajajah Limestone Member, and Lina Shale Member. In order to establish a stratigraphic revision of the Formation, a reference section near Al Kharj, southeast of Riyadh in central Saudi Arabia, was logged and a hierarchical organization of the depositional sequences established. The Aruma corresponds to four third-order cycles bounded by erosional unconformities. Integrated biostratigraphical data mainly based on ammonites, nannoflora, rudists, and larger foraminifera point to a Maastrichtian age for the Khanasir and Hajajah members, and a Paleocene age for the Lina Member. Regional stratigraphic correlations were established within the outcropping Aruma Formation in Saudi Arabia. Biostratigraphy and sequence stratigraphy allowed a correlation framework to be proposed between the Aruma and the Qahlah and Simsima formations of the United Arab Emirates and the Oman Mountains, and with the Sharwayn Formation of the Hadramawt and Dhofar. The high-resolution stratigraphic scheme established for the Aruma Formation in Saudi Arabia is expected to be useful for subsurface correlations and in petroleum exploration.
Palynological biozonation of the Permian of Oman and Saudi Arabia: progress and challenges
Authors: Stephenson Mike H. , Osterloff Peter L. , Filatoff John
Published: October 2021

Extensive palynological work in sequences in Oman and Saudi Arabia, has allowed a framework of eight biozones for the uppermost Carboniferous to Permian rocks in that region. Five of these are established in the palyniferous uppermost Carboniferous to Lower Permian sequence in Oman, and to some extent these are recognisable in sequences of central and southern Saudi Arabia. OSPZ1 (Oman and Saudi Arabia Palynological Zone 1), associated with the lower parts of the Al Khlata Formation and the Unayzah C member, is probably Stephanian in age. OSPZ2 is Asselian-Sakmarian in age, and is associated with the upper part of the Al Khlata Formation and the Unayzah B member. OSPZ3, which is subdivided into three sub-biozones, is associated with the Lower Gharif member; its age may lie in the range late Sakmarian to Artinskian, based on palynology and brachiopod-based ages for the Haushi Limestone, locally present toward the top of the Lower Gharif member. The composition of assemblages from OSPZ1 to OSPZ3 is similar to that of coeval sequences in other former Gondwana countries and the chronostratigraphical ages assigned to them are partly gained from correlation with faunally-calibrated Western Australian palynological biozones. At the level of OSPZ4, such correlation becomes difficult because significant differences are evident between Western Australian and Arabian assemblages, and because other Gondwana palynological biozonations, with which Arabia has greater affinity, are poorly constrained chronostratigraphically. OSPZ4 and the succeeding two biozones are established in the sporadically palyniferous Middle and Upper Permian sequences of Oman and Saudi Arabia. OSPZ4, though poorly characterised due to low palynological recovery, is probably ‘mid-Artinskian’ to Kungurian in age, and is associated with the Middle Gharif member. OSPZ5, present in southeast Saudi Arabia and Oman appears to be associated with the lower to middle parts of the Upper Gharif member, and is constrained in age, partly by the faunally-dated overlying Oman Khuff carbonates, as being Roadian or earliest Wordian in age. So far the assemblages of the highest biozone, OSPZ6, have been recovered only from the ‘basal Khuff clastics’ of central Saudi Arabia, and are believed to be younger than those of OSPZ5; dating by palynological means is difficult but recent microfaunal studies of the ‘basal Khuff clastics’ suggest a Capitanian age. Further study in appropriate palyniferous sections in other Middle Eastern countries may allow a more complete palynological succession to be established.
Foraminifers and algae from the Khuff Formation (late Middle Permian-Early Triassic) of central Saudi Arabia
Authors: Vachard Daniel , Gaillot Jérémie , Vaslet Denis , Le Nindre Yves-Michel
Published: October 2021

Algae and smaller foraminifers of the eponymous Khuff Formation (Saudi Arabia) principally comprise Permocalculus, biseriamminids, hemigordiids and lagenids. Due to the end-Capitanian crisis (Late/Middle Permian boundary) and the regional palaeoecology, fusulinids are rare and only represented by Nankinella sp. and Eostaffella? sp. Palaeofusulinids are completely lacking. New age data shows that these foraminifers correspond to the complete Lopingian (Late Permian) as indicated by several species of Paradagmarita. The position of the Triassic/Permian Boundary is approximately characterised, but requires more accurate studies. Forty-three taxa were identified, mostly in open nomenclature. One new species is described: Glomospirella? linae n. sp. The foraminiferal assemblage is correlated with several associations in Iran, Turkey, Transcaucasia and south China.
The debate over Hubbert’s Peak: a review
Authors: Al-Husseini Moujahed
Published: October 2021

The application of various quantitative techniques and assumptions by different authors to forecast the world’s conventional crude oil production in the 21st Century results in highly inconsistent predictions. The forecasts attempt to pinpoint the peak world oil production year (Hubbert’s Peak), peak production rate, and post-peak decline rate, based on estimates of the ultimate recoverable reserves (EURR). These techniques, pioneered by M.K. Hubbert in the mid-1950s, generally consider economic factors, such as the price of oil, as irrelevant in the long run. Some authors support a Low EURR World Scenario (about 2.0 trillion barrels, of which half has already been produced) and forecast Hubbert’s Peak in this decade. Other authors estimate the EURR at about 3.0 trillion barrels (Median EURR World Scenario), and this estimate is the mean EURR assessment of the United States Geological Survey and similar to assessments by several major oil and gas companies. An EURR of 3.0 trillion barrels implies Hubbert’s Peak will occur in 2020, or so, at a production rate of about 90–100 million barrels/day (compared to 85 million barrels/day in late 2005). A few authors support a High EURR World Scenario (4.0 trillion barrels or more) with Hubbert’s Peak in 2030 at a rate of 120 million barrels/day. Sensitivity analysis for Hubbert’s Curve suggest that Hubbert’s Peak moves by three years for every 200 billion barrels of error in the EURR.
Advances in Arabian stratigraphy: Origin and stratigraphic architecture of glaciogenic sediments in Permian-Carboniferous lower Unayzah sandstones, eastern central Saudi Arabia
Authors: Melvin John , Sprague Ronald A.
Published: October 2021

In the subsurface of eastern central Saudi Arabia, deposition of lower Unayzah sediments commenced in late Carboniferous (late Moscovian = late Westphalian-Stephanian) times during the earliest stages of the late Paleozoic Gondwanan glaciation. The Unayzah C member is the lowermost unit, and comprises quartzose sandstones laid down on an extensive glacio-fluvial outwash braidplain upon the pre-Unayzah unconformity (so-called “Hercynian unconformity”). They were overridden during (probably several) glacial re-advances, when the sediments were thrust over each other during the construction of push moraines ahead of the advancing ice sheets. The upper surface of the Unayzah C member represents the final sub-glacial contact of this longlived series of glacial advances and retreats, and demonstrably represents a significant post-Unayzah C unconformity. Subsequent (early Permian) deposits represent the final glacial retreat phase. They include the Unayzah B member and a new, un-named middle Unayzah member that underlies the Unayzah A member.

The Unayzah B member is dominated by glaciogenic sediments, including highly deformed material attributed to seasonal push moraines (and hence representing minor glacial re-advances); ice-proximal, subaqueous outwash fans (high-energy lacustrine turbidites with associated dropstones, and massive diamictites); and ice-distal, glaciolacustrine deposits including laminites, stratified diamictites, ripple cross-laminated sandstones and mudrocks with associated dropstones. In contrast, the un-named middle Unayzah member is characterized by widespread, fine-grained red-beds, representing low-lying alluvial floodbasin deposits. Embedded within these occur aeolian and fluvial sandstones. A significant drainage event is thus implied between the Unayzah B member and the un-named middle Unayzah member. It is marked by a sharp contact between the two members that represents a regionally correlatable disconformity. The end of lower Unayzah deposition is represented in places by paleosol development, indicating a further disconformable contact, separating the un-named middle Unayzah member from the overlying Unayzah A member. This study significantly extends the record of the advance and retreat of the Gondwanan ice sheets in southern Saudi Arabia, and provides sufficient confidence to propose a degree of stratigraphic correlation with coeval deposits in Oman.
The geology of Khuff outcrop analogues in the Musandam Peninsula, United Arab Emirates and Oman
Authors: Maurer Florian , Martini Rossana , Rettori Roberto , Hillgärtner Heiko , Cirilli Simonetta
Published: October 2021

A revision of the stratigraphy of late Palaeozoic and early Mesozoic carbonates (Bih Formation) in the Musandam Mountains near Ras Al Khaimah, United Arab Emirates (UAE), clarifies the presence of deposits that are age-equivalent to the Late Permian and Early Triassic Khuff Formation. Biostratigraphic markers including benthic foraminifera and calcareous algae indicate a Permian age for the stratigraphically oldest outcrops ranging from late Wuchiapingian to late Changhsingian (K4 and K3 reservoir units in the subsurface). A Late Induan – Early Olenekian (Early Triassic) age is documented for the stratigraphically youngest outcrops. Sedimentological features, stacking patterns and microfacies of the Permian outcrops show strong affinity to the KS3 and KS2 Khuff sequences, dominated by high-energy bioclastic pack- and grainstone. The depositional environment of the Bih Formation is further characterised by a palynological evaluation of claystones and by XRD analysis of clay minerals. Spectral gamma-ray data from the outcrop, which indicate Uranium depletion following the extinction of Permian foraminifera, help to pinpoint the position of the Permian – Triassic boundary and to correlate the measured section with the subsurface. Some stratigraphic intervals in outcrop are affected by strong secondary dolomitisation and do not reflect the same diagenetic patterns as their subsurface counterparts. Patterns of secondary dolomitisation, however, indicate the flow of formation water and thus mimic pore-fluid flow in the subsurface reservoirs. The depositional facies show clear resemblances to the reservoir facies, and the studied outcrops most likely represent the best analogue to the Khuff reservoirs in the UAE and in the North Dome/South Pars field area, offshore Qatar and Iran.
Opening of the Neo-Tethys Ocean and the Pangea B to Pangea A transformation during the Permian
Authors: Muttoni Giovanni , Gaetani Maurizio , Kent Dennis V. , Sciunnach Dario , Angiolini Lucia , Berra Fabrizio , Garzanti Eduardo , Mattei Massimo , Zanchi Andrea
Published: October 2021

We studied the stratigraphy, composition, and paleomagnetic properties of lateritic weathering profiles of Permian age from northern Iran and western Karakoram, Pakistan. A limited set of samples deemed representative yielded stable low-inclination paleomagnetic components carried essentially by hematite of chemical origin isolated in massive, fine-grained, and homogeneous ferricrete facies. These laterites originated at equatorial paleolatitudes characterized by intense weathering processes under warm and humid climatic conditions. Paleomagnetic estimates of paleolatitude from Iran, Karakoram, and north Tibet from this study and the literature, albeit sparse, provide testable constraints on the motion of the Cimmerian terranes as the result of the opening of the Neo-Tethys Ocean along the eastern margin of Gondwana during the Permian. We confirm and help refine previous suggestions that the Cimmerian terranes migrated from southern Gondwanan paleolatitudes in the Early Permian to subequatorial paleolatitudes by the Middle Permian – Early Triassic. As a novel conclusion, we find that timing, rates, and geometry of Cimmerian tectonics are broadly compatible with the transformation of Pangea from an Irvingian B to a Wegenerian A-type configuration with Neo-Tethyan opening taking place contemporaneously essentially in the Permian.
Decastroia razini n. gen. n. sp. – A new alveolinacean (foraminifera) from the Cenomanian of Socotra Island (Yemen)
Authors: Vicedo Vicent , Serra-Kiel Josep
Published: October 2021

The architecture of a new alveolinacean, Decastroia razini, from the Cenomanian shallow-water sediments of Socotra Island is described. The shape of the new genus is globular to slightly elongated. The internal structure is characterised by septula and floors that individualise two rows of superposed tubular chamberlets, an upper row of large, cortical chamberlets and a lower row of small, medullar ones. The chamberlets of the same chamber are communicated by preseptal passage.
Nukhul Formation in Wadi Baba, southwest Sinai Peninsula, Egypt
Authors: Hewaidy Abdel Galil A. , Farouk Sherif , Ayyad Haitham M.
Published: October 2021

The Nukhul Formation is the oldest syn-rift rock unit in the Gulf of Suez rift system in Egypt. The age of the formation is inadequately resolved by biostratigraphy and it is generally assigned to the Lower Miocene by stratigraphic position. For this study a surface section was measured and sampled at Wadi Baba, located in the southwestern Sinai Peninsula. It yielded 17 planktonic foraminiferal species and 17 foraminiferal benthonic species. The planktonic foraminiferal assemblage was used to divide the formation into two planktonic foraminiferal zones: (1) Globigerina ciperoensis Zone (O6) of Late Oligocene Chattian age; and (2) Globigerinoides primordius Zone (M1) of Early Miocene Aquitanian age. The two zones coincide with depositional sequences: (1) Chattian Lower Nukhul Sequence, with its upper boundary coinciding with the Chattian/Aquitanian (Oligocene/Miocene) boundary; and (2) Aquitanian Upper Nukhul Sequence, with its upper sequence boundary coinciding with the Aquitanian/Burdigalian boundary.
Ediacaran–Cambrian Sirab Formation of the Al Huqf region, Sultanate of Oman
Authors: Nicholas Christopher J. , Gold Sophia E.P.
Published: October 2021

The Ediacaran–Cambrian Ara Group of the South Oman Salt Basin in the Sultanate of Oman is one of the world’s oldest petroleum systems and holds some of the most important hydrocarbon reserves in the country. However, the Ara Group salt and isolated carbonate platforms, or ‘stringers’, are known only from the subsurface and deformed fragments brought to the surface in salt-piercing domes. Thus, determining Ara source and reservoir facies architecture at high resolution is a particular problem. Here we present the results of field surveying in the Haushi-Huqf region over a number of years specifically to investigate the possibility of Ara Group equivalents being exposed in outcrop. Defined here, for the first time, is the new Sirab Formation, which we incorporate into the top of the Neoproterozoic–Cambrian Huqf Supergroup. In general, it conformably overlies the Buah Formation. However, at some localities on what were probably fault-bounded palaeo-topographic highs, the Sirab Formation rests unconformably on eroded Buah Formation or directly on the even older Shuram Formation. The Sirab Formation is overlain with marked angular unconformity by the siliciclastics of the Haima Supergroup. As such, the Sirab Formation occupies the same lithostratigraphic position as the Ara Group subsurface. We subdivide the formation into three principal members; the lower Ramayli Member, middle Shital Member and upper Aswad Member. A fourth, the Salutiyyat Member, can be recognised where the Sirab Formation lies on eroded Nafun Group palaeo-topographic highs and is probably the chrono-stratigraphic lateral equivalent at least in part of the upper Ramayli Member. The Ramayli and Shital members contain evaporite units, including halite beds, and fault- or eustatically-controlled cyclical peritidal carbonates indicating that the Al Huqf area was a shallow trough or graben during this period within a regional structural high. The middle and upper members contain significant microbial build-ups including thrombolite framestone reefs, which are the principal reservoir subsurface in the Ara ‘stringers’, and rare crinkly laminites which are the presumed source rock at depth. Whilst the precise age dates for the formation and chronostratigraphy of each member still need to be resolved, it is clear that the Sirab Formation includes exposures of litho- and bio-facies present in the Ara Group and thus could provide useful surface analogues for the petroleum geology of the South Oman Salt Basin and Central Oman High in the future.
Impact of diagenesis on the spatial and temporal distribution of reservoir quality in the Jurassic Arab D and C members, offshore Abu Dhabi oilfield, United Arab Emirates
Authors: Morad Sadoon , Al-Aasm Ihsan S. , Nader Fadi H. , Ceriani Andrea , Gasparrini Marta , Mansurbeg Howri
Published: October 2021

This study is based on petrographic examination (optical, scanning electron microscope, cathodo-luminescence, backscattered electron imaging, and fluorescence) of 1,350 thin sections as well as isotopic compositions of carbonates (172 carbon and oxygen and 118 strontium isotopes), microprobe analyses, and fluid inclusion microthermometry of cored Jurassic Arab D and C members from 16 wells in a field from offshore Abu Dhabi, United Arab Emirates. The formation was deposited in a ramp with barrier islands and distal slope setting. Petrographic, stable isotopic and fluid-inclusion analyses have unraveled the impact of diagenesis on reservoir quality of Arab D and C within the framework of depositional facies, sequence stratigraphy, and burial history. Diagenetic processes include cementation by grain rim cement and syntaxial calcite overgrowths, formation of moldic porosity by dissolution of allochems, dolomitization and dolomite cementation, cementation by gypsum and anhydrite, and stylolitization. Partial eogenetic calcite and dolomite cementation has prevented porosity loss in grainstones during burial diagenesis. Dolomitization and sulphate cementation of peritidal mud are suggested to have occurred in an evaporative sabkha setting, whereas dolomitization of subtidal packstones and grainstones was driven by seepage reflux of lagoon brines formed during major falls in relative sea level. Recrystallization of dolomite occurred by hot saline waters (Th 85–100°C; and salinity 14–18 wt% NaCl). Anhydrite and gypsum cements (Th 95–105°C; fluid salinity 16–20 wt% NaCl), were subjected to extensive dissolution, presumably caused by thermal sulfate reduction followed by a major phase of oil emplacement. The last cement recorded was a second phase of anhydrite and gypsum (Th 95–120°C; 16–22 wt% NaCl), which fills fractures associated with faults.
Imaging subtle faults using azimuthal coherence attribute: A case study from Central Saudi Arabia
Authors: Alqahtani Faisal , Al-Shuhail Abdullatif A.
Published: October 2021

The coherence attribute is an edge detection method that is widely used for interpreting faults on 3-D seismic time slices. The traditional coherence attribute is calculated on migrated volumes using traces from all available azimuths. It has recently been shown that calculating coherence along specific azimuths can enhance the detection of faults running perpendicular to those azimuths. In this study, we applied azimuthal coherence attribute analysis on a 3-D seismic data set from a gas field in Central Saudi Arabia. We generated four migrated 3-D data volumes sorted by azimuth in addition to a conventional full-azimuth volume. We then calculated the coherence attribute for all volumes and compared each azimuthal coherence volume to the conventional full-azimuth coherence volume. The azimuthal coherence results exhibited an improved definition for faults whose strikes are perpendicular to the sorting azimuth. More specifically, systems of NW-trending discontinuities were imaged more clearly in the NE-SW oriented coherence volume than it was in the full-azimuth coherence volume. The reason for this enhancement is the fact that seismic waves tend to avoid passing through the fault when they propagate parallel to the fault strike therefore missing the effects of the fault while they must pass through the fault when propagating perpendicular to the fault strike which results in better illumination of the fault.
Middle Permian (Guadalupian) fusulinid taxonomy and biostratigraphy of the mid-latitude Dalan Basin, Zagros, Iran and their applications in paleoclimate dynamics and paleogeography
Authors: Davydov Vladimir I. , Sakineh Arefifard
Published: October 2021

The Middle–Upper Permian (Guadalupian–Lopingian) Dalan Basin was part of a very large carbonate ramp/platform along the passive margin of the Arabian Plate, located at mid-latitude Neo-Tethys Ocean. As shown in the modern world the mid-latitudes are areas where climatic fluctuations and velocity of climate change are most significant. Consequently, the most significant variations in foraminiferal diversity occur at higher latitudes as already noted for the Middle Permian (Guadalupian) foraminifers’ record. The fusulinids as a large, warm-water foraminifera were quite sensitive to water temperature. The optimal water temperature for recent warm-water benthic foraminifera with living symbionts, and consequently for fusulinids, is 20–30°C, while the lower limit is 14–16°C. Three climatically-determined assemblages were distinguished in Zagros and the surrounding areas. The first assemblage is characteristic of temperate, cool-water environments and contains smaller foraminifera with no symbionts, which possess resistance to such environments. Fusulinid staffellids, schubertellids, Chusenella, Eopolydiexodina and Monodiexodina can be found in the warmer water environments in a second climatic assemblage, transitional from temperate- to warm-water state. The third assemblage is characterized by the presence of verbeekinids in warm-water conditions in Zagros and appeared where surface-water temperature exceeded approximately 25°C. The proposed model of climate fluctuations and paleogeography in the Neo-Tethys is based on analyses of temporal and spatial distribution of fusulinids. Also, a temperate cool-water Monodiexodina is recorded in this area for the first time. Three new species of fusulinids are described.
Carbon-isotope signatures of Albian to Cenomanian (Cretaceous) shelf carbonates of the Natih Formation, Sultanate of Oman
Authors: Vahrenkamp Volker C.
Published: October 2021

The δ13C values of Albian to Cenomanian shallow-marine carbonate sequences of the Natih Formation have been collected from subsurface cores of a key location in Oman. The 450-m-thick stack of shelf carbonates is without significant gaps in deposition. The δ13C data range between 1‰ and 6‰, more-or-less tracking the evolution over time of δ13C in seawater established elsewhere in time-equivalent pelagic carbonate sequences. Anchored by biostratigraphy the isotope profile suggests several additional time correlations. It thus provides significantly enhanced stratigraphic resolution and a key section for regional correlations. In particular, the onset of Natih deposition (Natih F and G members) coincides with the Albian/Cenomanian boundary event, thus placing the base Natih into the Albian. The Natih C and D members were deposited mainly during the Mid-Cenomanian oceanic anoxic event, while the carbon-isotopes signature of the Natih A Member, which is at this locality incomplete due to erosion, documents the onset of the Cenomanian/Turonian boundary event (OAE2). This indicates a latest Cenomanian, possibly Early Turonian age for the top Natih at this subsurface location and suggests an Early Turonian age for the more complete Natih section exposed in the nearby Oman Mountains sections.

Both organic-rich intervals of the Natih Formation (Natih E4b and B2) do not correlate with global Oceanic Anoxic Events indicating a rather local setting for source-rock deposition. This is further supported by an isotopic anomaly associated with the organic-rich Natih B. The anomaly is likely related to near-seabed diagenesis or a temporary limited water exchange of the intra-shelf basin with the open ocean and the incorporation of recycled carbon from oxidized organic matter into the water column and the inorganic carbon pool. The subsurface carbon-isotope profile correlates well with those from nearby outcrop and other subsurface sections adding further confidence that primary signatures are preserved and can be used for correlations. As in other Early Cretaceous shelf sequences of the Arabian Plate oxygen isotopes are lighter than expected for calcite deposited in equilibrium with Cretaceous seawater indicating most likely whole-scale recrystallization and stabilization during shallow burial at slightly elevated temperatures.
Geochemical characterisation, volumetric assessment and shale-oil/gas potential of the Middle Jurassic–Lower Cretaceous source rocks of NE Arabian Plate
Authors: Aqrawi Adnan A.M. , Badics Balazs
Published: October 2021

The Middle Jurassic–Lower Cretaceous strata of the NE Arabian Plate contain several prolific source rocks providing the charge to some of the largest world-class petroleum systems. They are located within the Zagros Fold Belt and Mesopotamian Foreland Basins covering the northern, central and southeastern parts of Iraq, Kuwait and western and southwestern Iran, particularly the Lurestan and Khuzestan provinces. These source rocks include the Bajocian–Bathonian Sargelu, the Callovian–Lower Kimmeridgian Naokelekan and the Upper Tithonian–Lower Berriasian Chia Gara formations of Iraq and their chronostratigraphic equivalents in Kuwait and Iran. They have charged the main Cretaceous and Cenozoic (Tertiary) reservoirs throughout Iraq, Kuwait and Iran with more than 250 billion barrels of proven recoverable hydrocarbons.

These formations represent the transgressive system tracts of sequences deposited within deep basinal settings and anoxic environments. They are dominated by black shales and bituminous marly limestones, with high total organic carbon (TOC) contents (ranging from 1–18 wt%), and by marine Type IIS kerogen. Their Rock-Eval S2 yields may reach up to 60 mg HC/g Rock, particularly along the depocentre of the Mesopotamian Foreland Basin. The immature hydrogen index (HI) values might have been up to 700 mg HC/g TOC, whereas the present-day observed values vary depending on the location within the basin and the present-day maturity. The Source-Potential Index (SPI; i.e. mass of hydrocarbons in tons, which could be generated from an area of 1 sq m in case of 100% transformation ratio) averages around 2–3, but can even reach up to 14–16 along the basins’ centres.

The Sargelu and the overlying Naokelekan-basinal Najmah formations (and their equivalents) could represent the best potential shale-gas/shale-oil plays in Iraq, Kuwait and Iran, due to their organic richness, favourable maturity and the presence of regional upper and lower seals. The estimated oil-in-place for the potential Sargelu shale-oil play in Iraq only is around 1,300–2,500 billion barrel oil-equivalent (BBOE) and in Kuwait is about 7–150 BBOE.