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Third EAGE Workshop on Arabian Plate Geology
- Conference date: 28 Nov 2011 - 01 Dec 2011
- Location: Kuwait City, Kuwait
- ISBN: 978-94-6282-058-6
- Published: 28 November 2011
51 results
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Global to Regional Plate Tectonics during the Permo-Triassic
Authors C. van Oosterhout and M. PoppelreiterPlate reconstructions prior to the Jurassic, lack the calibration from Oceanic seafloor, which is not preserved. Only the continental fragments can be constraint with paleomagnetic and other geosocience data. The objective of this study is to bring together the key geosciences data to constrain the plate model to be able to explain the Khuff Formation Development and deformation. Global constraints are needed in order to get a sensible plate tectonic model that underpin the evolution of the Permo-Triassic Khuff Formation along the passive margin of the Neo-Tethys Ocean. Most geodynamic scenarios describe the plate tectonic process as an oceanic Tethys slab subducting under the Eurasian craton. Such models suggest subsequently tearing of a ribbon-like suit of continental basement terranes called ‘Cimmerian’ from the Gondwana margin to form the Neo-Tethys Ocean. The subduction zone subsequently consumes the Neo-Tethys as the Cimmerians terranes dock onto the Eurasia margin. This slab-pull and slab-push sequence of events has important implications for the Africa-Arabia margin.
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Sequence Stratigraphy, Reservoirs, Diagenesis and Hydrocarbon Contents in the Khuff Formation and its Equivalents: Independent or Linked?
More LessThirty years ago, the author undertook a detailed sedimentological, petrographic and reservoir quality evaluation of extensive cores through the Khuff Formation from Well Zakum-182 in offshore Abu Dhabi. Many new observations, including detailed depositional and early diagenetic fabrics preserved during dolomite replacement and the presence of sulphur as a late diagenetic phase infilling the cores of anhydrite nodules, vugs and fractures, ignited a lifelong interest in this fascinating formation and its equivalents, notably the Dalan and Kangan formations of Iran. This was followed by a much larger project in which the author, as part of a multi-disciplinary team, was responsible for a regional analysis of the sedimentology, diagenesis and reservoir quality of the Khuff Formation over a wide area ranging from subsurface sections in Abu Dhabi, Dubai and Qatar to outcrops in Saudi Arabia, Oman and the Musandam Peninsula.
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The Khuff Formation in the Middle East: New Insight into Regional Stratigraphy and Palaeoenvironmental Reconstruction using Bio-assemblages and Facies Analysis
Authors Jérémie Gaillot, A. Virgone, B. Caline and G. Frébourg and F. GisquetA multidisciplinary synthesis of outcrop and subsurface data of the carbonates and evaporites of the Late Permian Khuff Formation was carried out in order to constrain the spatial and stratigraphic distribution of the depositional facies.
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Review of the Permian–Triassic Gas Play in the Arabian Gulf Region
More LessSignificant amounts of non-associated gas reserves are proven from the Permian–Triassic Khuff-Dalan play across the Arabian Gulf region (Figure 1). This play is part of the Paleozoic petroleum system that is mainly sourced by the base Qusaiba hot shale of the Silurian Qalibah Formation. It is sealed by the Triassic Sudair-Aghar shales (Figure 2) and trapped in high relief, north-trending anticlines or salt domes.
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Khuff Formation in Kuwait: An Overview
Authors R. Husain, D. Ahmad Khan and A. Sajer and N. Al-AmmarThe Khuff Formation represents an intra-Late Permian, Tatarian transgression over a varied topography in Kuwait. The formation occurs at greater depth in comparison to adjoining regions and is fully penetrated only in the wells located over the Kuwait Arch. The formation comprises mainly dolomudstone, foraminiferal and algal dolowackestone, peloidal and algal dolopackstone, peloidal and oolitic dolograinstone, anhydrite and minor limestone deposited in evaporitic low energy inner to middle ramp setting. Dominantly supratidal to subtidal, restricted setting and hypersaline conditions were prevailing during the deposition. Dolomitization has caused rare development of intercrystalline porosity, however mostly over dolomitization coupled with anhydrite cementation has deteriorated the porosity.
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The Opening of Neo-Tethys and the Formation of the Khuff Passive Margin
More LessAny investigation of regional geology and palaeomagnetism in the Middle East will show that in the Permian a series of terranes separated from Gondwana and drifted north, opening the Neo-Tethys Ocean in their wake. To the north of these terranes, the Palaeo-Tethys Ocean closed and was largely subducted. Eventually in a non-synchronous movement but largely in Late Triassic and Early Jurassic times, these terranes docked with the northern margin of the former Palaeo-Tethys during the Cimmerian Orogeny.
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Multi-scale Assessment of the Middle Eastern Permian–Triassic Khuff Carbonate: Structural Evolution and its Impact on Reservoir Properties
Authors M. Vroon and V. Zampetti and R. BorkhatariaThe Khuff Petroleum System Study is a multi-scale, multi-disciplinary analysis that integrates subsurface and outcrop, rock and fluid samples, and static and dynamic data in order to characterize the Permian–Triassic Khuff carbonate, one of the major petroleum reservoirs in the Middle East region. At regional scale, the Khuff carbonate shows a variety of depositional environments (with facies ranging from coastal plain anhydritic claystone, tidal flat/low-tohigh energy lagoonal deposits to open-marine dolostones alternating with grainy limestones and high-energy shoal-dominated dolostone/thick grainy limestones) and thicknesses (from near zero at the pinch-out of siliciclastic facies in Central Saudi Arabia, to more than 400 m (1,300 ft) in Ghawar Field in northern Saudi Arabia, expanding to 800 m (2,600 ft) in the North field, Qatar and to nearly 1,000 m (3,300 ft) in the eastern United Arab Emirates.
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Hydrocarbon Potential of the Upper Permian Chia Zairi Formation in Northwest Iraq
Authors Aboosh H. Al-Hadidy and Adnan A.M. AqrawiIn Iraq the Upper Permian Chia Zairi Formation, together with the overlying Lower Triassic Mirga Mir Formation, forms the chronostratigraphic equivalent for the Khuff Formation of eastern Arabia and the Dalan and Kangan formations of Iran. The Chia Zairi Formation extends from upper-north Ora outcrops near the Turkish border to southern Iraq (wells West Kifil-1 and Diwan-1), thus covering central and eastern parts of the country. It is absent in the far western deserts at the Jordanian border and some areas near the Syrian border (i.e. Khelsia High region and south of Jabal Sinjar) due either to non-deposition or erosion. Lithologically, the Chia Zairi Formation is composed of both carbonates and siliciclastics, and the carbonate proportion increases northward and eastward. However, the formation is deeply buried in most regions except from the northwestern and potentially southwestern region too, where, based on seismic, it is estimated to be around 3–5 km deep.
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Khuff Reservoir in Offshore Abu Dhabi Field; Future and Challenges
Authors O. Saif, M. E. Elsaid and T. El-Din Hamdy and H. Bu FutaimOffshore Abu Dhabi lies on the eastern part of the Arabian platform. The area is situated between two major structural highs, the Qatar Arch to the west and the Oman mountains to the east. This area has undergone relatively grater subsidence throughout post Lower Permian history resulting in the accumulation of a thick sedimentary section; the Upper Permian to recent section alone has a thickness in excess of 17000 ft. Structural development is typical of the Arabian Platform, being characterized by gentle simple folds, some of which are quite large. These folds are regarded as the expression of periodic re-activation of North-South aligned deep-seated basement features. In addition, salt tectonics has played a rule in the development and modification of structures in the area. A period of uplift and erosion terminated the clastics deposition of the Paleozoic.
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Carbon- and Oxygen-isotope Stratigraphy: A Tool for Confirming Sequence Stratigraphy in the Early Triassic Kangan Formation, Northern Part of the Arabian Plate
Authors Fadi H. Nader, H.R. Pour-Bonab and M.R. Kamali and M. PeyraviThe Early Triassic Kangan Formation, which is equivalent to the Upper Khuff Formation, is the main reservoir for natural gas in southwest Iran and the northern Gulf. Investigations of this formation in offshore “Field A” indicate that it is composed of 14 facies deposited in tidal flat, lagoon and oolitic barrier settings in the inner part of a carbonate ramp or platform. Vertical variations of microfacies and gamma-ray, log profiles show that the formation consists of three depositional sequences (KG1 to KG3), each consisting of transgressive and highstand systems tracts and each bounded above by a Type-2 unconformity. Carbon- and oxygen-isotope profiles from a well-dated carbonate section were compared to sedimentological data and the results from a sequence-stratigraphic study. The profiles showed negative and positive peaks coinciding with sequence boundaries and maximum flooding surfaces, respectively.
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Stratigraphic Controls on Carbonate Evaporite Stratigraphy - Importance to Hydrocarbon Exploration: Examples from Middle Eastern Oil Fields and Their Response to Plate Tectonic Cycle, Climate, Basin Position and Sea Level
More LessPaleozoic, Mesozoic through Cenozoic sedimentary fill of the Tethys southern margin is subdivided stratigraphically by the beat of second- and third-order changes in eustasy, tectonic movement, sediment supply and Wilsonian cycles of plate movement. This northeastern flank of Gondwanaland extends from the Arabian Plate through Zagros and Taurus Mountains, Levant and North Africa. Regional chronostratigraphic charts and crosssections detail products of these processes and major petroleum production from carbonates and evaporites interbedded with clastic sequences; with flatter-lying horizons in Arabia, folded in the Zagros and Taurus Mountains of Iran and Turkey, wrenched margin through the Levant and disrupted block-faulted terrains in North Africa from Egypt through Libya.
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The Khuff Outcrop Project in the Oman Mountains: Framework and Research Approach
Authors T. Aigner and M. PöppelreiterThis overview presentation introduces an extensive outcrop analog study that has been ongoing for more than three years on the Khuff-equivalent strata in the central Oman Mountains, Sultanate of Oman. This project is focussed on the sequence stratigraphy and the stratigraphic architecture of grainstone bodies as potential reservoir analogs for the subsurface. An integrated multi-dimensional, multi-disciplinary and multi-scale approach led to a series of nested reservoir models that allow to better understand controlling factors and to destill some general trends. The results may be directly used (1) to reduce uncertainties on near well- and field-scale correlation, (2) in reservoir modelling of analogous fields, and (3) as predictive rules in exploration. This overview is followed by detailed presentations on the various Khuff sequences.
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Khuff Sequence KS6: Paleorelief-influenced Facies and Sequence Patterns in the Lower Khuff Formation, Sultanate of Oman
Authors D. Bendias, T. Aigner and M. Pöppelreiter and B. KöhrerThis outcrop analog study of Lower Khuff Sequence KS6 (Saiq Formation) aims to capture lateral reservoir facies distribution during the initial phase of basin-fill. The Hercynian tectonic event triggered the erosion of Cambrian to Carboniferous strata in Oman and formed the topography of the Sub-Khuff Unconformity. When the Neo-Tethys Ocean flooded the Arabian Shield clastic sediments, the so-called "Basal Khuff Clastics" became preferentially deposited in possible paleo-lows. One main objective of this study was to unravel the effect of this paleo-relief on reservoir facies distribution within the overlying sediments.
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Khuff Sequence 5 (KS5), Oman Mountains: Lateral Facies and Sequence Variability – a Record of Differential Subsidence?
More LessThis study focuses on the sequence stratigraphy and 3-D modelling of the Khuff Sequence 5 (KS5) in the Oman Mountains (Al Jabal al-Akhdar), Sultanate of Oman. The Lower Khuff sequences (KS5 and KS6) are at this stage poorly understood, since most of the reservoir units are located in the Upper and Middle Khuff sequences (KS1 to KS4). Previous studies (Koehrer et al., 2010, 2011) revealed layer-cake geometries of grainstone bodies in the Middle and Upper Khuff sequences (KS1 to KS4) on outcrop to exploration scales. The key question of this study was if the layer-cake geometries continue to be present or are different in the KS5.
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Khuff Sequence KS4: High-resolution Anatomy of a Middle Khuff Grainstone Package, Oman Mountains, Sultanate of Oman
Authors M. Haase and T. Aigner and H. ForkeThis outcrop study is part of a larger-scale project on the Saiq Formation in the Oman Mountains (outcrop analog of Khuff Formation), and focussed on the small-scale heterogeneities of the lower part of Khuff Sequence 4 (KS4). This interval is dominated by massive grainstones that at first glance seem extremely homogenous with distinct trough cross-bedding detectable in spite of strong dolomitization. Serrated gamma-ray patterns made small-scale cycle interpretations difficult. Therefore a very detailed facies and sequence analysis was necessary to decipher the vertical microfacies make-up of the grainstones and link it with potential pore types.
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Khuff Sequences KS1 to KS4: Grainstone Geobodies in the Middle and Upper Khuff of the Oman Mountains, Sultanate of Oman
Authors B. Koehrer, M. Zeller and T. Aigner and M. PöppelreiterThis study is part of a research project on Khuff grainstone bodies carried out in the Al Jabal al-Akhdar area (Oman Mountains) in the Sultanate of Oman (Figure 1) and focusses on Khuff sequences KS1 to KS4. Its aim was to unravel the Khuff stratigraphic architecture on hierarchical scales to understand geometries and textural variation of grainstones as potential reservoir bodies. Hierarchical static 3-D geological models were generated that visualise the sedimentary architecture of primary reservoir bodies using industry standard 3-D geomodelling software.
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Arid Region Carbonate Platforms: Middle East Reservoirs
More LessCalcitic grainstones and some dolomitic packstones are amongst the most common Middle East reservoir lithologies and they host some of the best hydrocarbon reservoirs in the world. They are well-sorted, winnowed carbonate deposits with little or no carbonate mud, normally formed in moderate to warm shallow-water, high-energy settings. Substantial accumulations of this facies may form in relatively shallow, subsiding basins so that deposition and subsidence remain in balance thus permitting continuous deposition. Where these sediments remain only partially cemented, fairly open porosity is maintained and upon burial there is only moderate compaction and such sediments can act as excellent hydrocarbon reservoirs. The packstones accumulated both downslope from the grainshoals and updip to their lea. Their porosity is in part depositional and in part diagenetic.
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Basement Configuration and its Impact on Permian–Triassic Prospectivity in Kuwait
Authors P. Singh, R. Husain and A. Al-Kandary and A. Al-FaresPetroleum exploration efforts to date primarily have been focused on the Cretaceous and Jurassic targets and very little effort has been made for exploring deeper prospects in Kuwait. The seismic data quality due to its infestation with multiples does not allow for mapping the deeper prospects with confidence. For meeting this objective, an integrated modelling of seismic, gravity, magnetic and borehole data is carried out for generating a basement configuration map to evaluate the likely preservation of the Lower Silurian Qusaiba hot shale. The Qusaiba hot shale is the source for some of the most important petroleum systems of the Middle East and is believed to have charged the Devonian Jauf, Carboniferous–Permian Unayzah and Permian–Triassic Khuff formations.
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The Arabian Plate and the IGC Programme 572 (Permian–Triassic Extinction and Recovery): Results From the Muscat - Gutech (German University of Technology in Oman) Field Meeting (February 2010)
Authors A. Baud, M. Bernecker, L. Krystyn, S. Richoz, O. Weidlich, B. Beauchamp, F. Cordey and S. Grasby and Ch. HendersonThe Permian–Triassic transition has been surveyed in the Oman Mountains and new detailed sections have been presented (Baud and Bernecker, 2010), from autochthonous shallow-water units (Saih Hatat and Al Jabal al-Akhdar) to slope deposits in the Jabal Sumeini area (Wadi Maqam units), from distal tilted block (Wadi Wasit) to oceanic deep-water deposits (Buday’ah).
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Upper Permian to Lower Triassic Carbon Isotope Record in the Oman and Zagros Mountains: An Overview from the Shallow Platform to the Basin
Authors S. Richoz, A. Baud and L. Krystyn and M. HoracekThe Oman Mountains as well as the Zagros Mountains expose a segment of Neo-Tethyan southern margin. We will review the 13C and 18O isotope curves in various sections from shallow- to deep-water facies zones for the Upper Permian–Lower Triassic carbonate sequences from Oman and show some preliminary results from Zagros. The shallow-water environment was measured in the Al Jabal al-Akhdar Mountains (Wadi Sathan section), the Saih Hatat (Wadi Sawat) and the Musandam (Wadi Shahha), and the slope carbonates of the platform margin in the Sumeini area (Wadi Maqam). Deep-water deposits from the basinal sector of the margin were studied in the Hawasina Nappes (Wadi Wasit South, Wadi Musjah and Buday’ah) and the Bata’in complex (Sal). Drowned carbonate platform (Oman Exotics) and tilted blocs of the platform have also been studied (Ba’id and Wadi Wasit block).
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Importance of Trace Fossils and Bioturbation in Carbonate Reservoir Characterization and Reservoir Quality: Examples from the Khuff Formation
By Dirk KnaustSeveral aspects of the study of trace fossils (ichnology) are relevant for the characterization of carbonate reservoirs, of which the following are most important: (1) facies interpretation by utilizing the ecological information of trace fossils and ichnocoenoses; (2) reservoir zonation by identifying sequence boundaries and flooding surfaces for correlation; and (3) reservoir quality and connectivity, which is directly affected by bioturbation. The vast shallow-marine carbonate platform of the Middle Permian to Lower Triassic Khuff Formation in the Middle East comprises broad facies belts with little significant changes in the lithofacies. However, trace fossil assemblages and ichnofabrics, in combination with sedimentological observations, serve in subdividing this platform and in distinguishing sub-environments. From proximal to distal, these are sabkha and salina, tidal flat, restricted lagoon, open lagoon, platform margin, shoreface/inner ramp, slope/outer ramp and basin/deeper intra-shelf. In this way, changes in relative sea level can be better reconstructed and guide the sequence stratigraphic interpretation.
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Uncertainties on Basal Khuff Clastics in Outcrop in Saudi Arabia
More LessVarious types of clastic and mixed clastic-carbonate deposits represent the transition from the pre-Hercynian and Hercynian Palaeozoic formations and the marine Khuff carbonate in Saudi Arabia. Due to sedimentary and erosional hiatuses, the complexity of this sedimentation is particularly reinforced near the outcrop and on top of the Central Arabian Arch or of the Rayn Plate. Therefore, age and lithostratigraphic assignments of the litho-units resting underneath the Khuff carbonate are often uncertain or questionable. In order to avoid unconsidered assignments to a particular formation of these sediments prior to any critical analysis of the retained criteria, this study proposes a review of typical uncertainties and proposals of clarification.
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Diagenetic Trends in Arid Carbonates: What Makes the Khuff Dolostone Reservoirs?
More LessNumerous studies and publications have shown that the Khuff reservoirs in the Middle East consist of carbonates that were deposited on shallow, hypersaline epeiric platforms. Hypersaline deposits are represented by evaporites, whilst carbonates correspond to the more open-marine conditions. The availability of diagenetic hypersaline brines favoured dolomitization and precipitation of anhydrite cements. Thus, a significant percentage of the Khuff Formation contains dolostones, which were formed during early diagenetic stages (sabkha and/or reflux dolomitization) and during burial (burial dolomitization and fault/fracture-related dolomitization).
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Khuff Formation in Kuwait: Depositional Facies and Diagenetic Control on Reservoir Characterization
Authors D.A. Khan, R. Husain and A.A. Sajer and M.M. Al-AjmiThe Permian–Triassic Khuff Formation holds huge oil and gas reserves in the Arabian Gulf region and is an important exploration target. The formation is poorly explored in Kuwait due to its occurrence at greater depths and hostile drilling environment. The Khuff Formation in Kuwait is divisible into A, B, C and D members. The Upper Khuff comprises A, B and C members and is separated from the Lower Khuff D Member by the Median Anhydrite.
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Diagenesis Control on Reservoir Properties of a Permian Triassic Carbonate Reservoir, North Oman
Authors S.Z. Al Farqani, I.G. Perez and M. Claps and H. PetersThe subsurface Permian–Triassic Khuff carbonates in North Oman are sour reservoirs with variable amounts of H2S and CO2. A diagenetic study was part of an integrated multidisciplinary project aimed to understand the origin and distribution of H2S, attributed either to bacterial or thermochemical sulphate reduction, and its relation to the hydrocarbon charge history for these reservoirs.
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Fracture Mineralization and Fluid Flow Evolution: An Example from the Permian–Triassic Carbonate Successions of United Arab Emirates
Authors I.S. Al-Aasm, S. Fontana, A. Ceriani and S. Morad and F.H. NaderFractures are often the primary conduits for pore fluids, and thus have important impact on the diagenetic and reservoir quality evolution of the host rocks. Therefore, fluid flow can be used to develop conceptual models for the spatial and temporal distribution and connectivity of reservoir porosity and permeability on a regional and basinal scale. In the context of the hydrocarbon-rich Middle East, the Permian–Triassic Khuff Formation hosts huge gas accumulations in the subsurface of the Arabian Plate. Reservoir properties of this formation are strongly influenced by depositional facies and diagenetic evolution (Ehrenberg et al., 2007; Fontana et al., 2010; Moradpour et al., 2008). In the Emirate of Ras Al Khaimah (RAK), in the northeast of the United Arab Emirates (UAE), there are excellent outcrops of the Permian–Triassic rock sequence, which is partly correlatable with the Khuff Formation (Strohmenger et al., 2002; Maurer et al., 2008, 2009). In this study, which involves fieldwork, petrographic, fluid inclusion and isotope (O, C and Sr) investigations, outcrops of Permian– Triassic carbonate rocks have been studied to relate fracture mineralization to tectonic history of the area.
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Permo-Triassic Source Rock Assessment by Inherited of the Triassic Oils in Kuwait
Authors R. Andriany and A. Al-KhamissTwo majors of the younger petroleum systems in Jurassic age of Najmah-Najmah (!) and Cretaceous age of Makhul-Burgan (!) have been identified and characterized. Crude oils trapped in the older reservoir of Triassic age at Mutriba and Kra Al-Maru fields showing different characters compared to the oils in younger systems. Biomarker, diamondoid, and carbon isotope are the most resistant compounds throughout the geological processes. Hence, the specific characteristics of crude oils trapped in Triassic reservoirs can be utilized for the source rock tracking. Genetic characters of the parent rock will be inherited to the oils produced. Oil and source rock are having a reciprocal relationship, by determining nature of the source rocks, the produced oil characters can be predicted and vice versa.
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The Khuff Impact on Unayzah Seismic Response: Umm-Jurf Field
More LessThe combined effects of variations in thickness and impedance in the Khuff Formation are significant and are sources of noise in the seismic image of the Unayzah Formation in the Umm Jurf Field. They obscure important reservoir signals and degrade the accuracy of the depth and thickness maps. The influence of these variations is readily seen on seismic time and horizon slices.
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Petrophysical Rock Types of the Khuff C - Eastern Saudi Arabia
By E. ClerkePetrophysical rock types (PRTs) can be defined as objects in the three dimensional space defined by Thomeer pore system parameters. Classifications in the Thomeer parameter space must also be accompanied by relationships to convenient well bore measurements (commonly well logs) and geologic parameters to create economic value in the petroleum business. Recent and detailed core-and-log-based high-frequency, sequence-stratigraphic characterization of the Khuff-C by Eid, Dukhayyil and Tawil are now complete and this work builds on that important geological foundation. Hence, any effort to define petrophysical rock types must include and utilize a host of multidisciplinary data.
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Reservoir Rock Characterization, Classification and Pore Typing in the Dalan/Kangan Carbonates (Khuff Analogues), South Pars Field
More LessThe South Pars Field, discovered in 1990, is part of the world's largest single gas accumulation located in the Gulf. The Iranian part of this immense gas accumulation accounts for 5% of the world’s and 60% of Iran's total gas reserves. This Field produces from Dalan/Kangan carbonates (Khuff analogues). These Permian–Triassic carbonate reservoirs in the field are highly stratified in nature and display layer-cake geometry. Combined core analysis and detailed thin section studies are used for facies analysis. Accordingly, 14 major facies were recognized in these carbonates. Facies analysis shows that their depositional setting was located along the inner part of an epiric carbonate system that extended from a peritidal setting to a shallow subtidal zone (back-shoal setting), passing over to a high energy shoal and fore-shoal facies (Figure 1).
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Integrated Biostratigraphy of the Saiq Formation (Al Jabal al-Akhdar, Oman Mountains) and its Implication for the Regional Correlation of Khuff Time-equivalent Deposits
Authors H. Forke, M. Pöppelreiter, T. Aigner, B. Koehrer, L. Walz and D. Bendias and M. HaaseWe present a multi-disciplinary approach (sequence-biostratigraphy, palaeoenvironmental analysis, gamma-ray, and carbon isotopes) for the stratigraphic subdivision of Khuff timeequivalent deposits in Oman (Saiq and lower Mahil Formation, Al Jabal al-Akhdar). The Khuff is herein subdivided into six third-order depositional sequences. According to the proposed biostratigraphic zonation, the KS6 to KS5 is Middle Permian (Roadian?–Wordian– Capitanian), the KS4 to basal KS2 is Late Permian and the remaining part of KS2 and KS1 is Early Triassic. Major biotic crises occurred during the upper KS5 (“end-Guadalupian faunal crisis”) and in the basal KS2 (“end-Permian faunal extinction”). The transition from Middle to Late Permian is further accompanied by a palaeoenvironmental shift from a differentiated bioclastic ramp to more uniform microbial-mediated platform deposits. The biozonation and biotic events have been applied to correlate outcrop sections and subsurface on a regional scale across the Arabian Platform.
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Sequence Stratigraphy and Reservoir Development of the Khuff Formation of the Arabian Plate
Authors A. Alsharhan and Ch.J. StrohmengerThe Middle Permian (Capitanian) to Early Triassic (Induan) Triassic Khuff Formation is a prolific gas reservoir of the Arabian Plate. It is composed of mainly shallow- water carbonates and evaporates, representing a second-order transgressive- regressive sequence, which is composed of seven third-order composite sequences (KS1-KS7). The maximum flooding surface of Khuff Sequence KS4 (Khuff MFS4 at ca. 258 Ma) is interpreted to also represent Khuff second-order maximum flooding. The transgressive system set of the Khuff second-order sequence starts with Khuff Sequence KS7 and ends at the Khuff maximum flooding surface of Khuff Sequence KS4 (Khuff MFS4). The highstand systems set starts on top of Khuff second-order maximum flooding surface and ends at the Top Khuff Formation (top of Khuff Sequence KS1).
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High-resolution Sequence Stratigraphy of the Late Permian Khuff-C in Hawiyah, Ghawar Field
Authors Ghazi Al Eid and Aus Al TawilThe Late Permian Khuff-C carbonates of the Khuff Formation in Ghawar Field are composed of four high-frequency sequences, Khuff-C1 to Khuff-C4 (KC1 to KC4), with numerous mappable small-scale shallowing-upward cycles that vertically partition the reservoir. Each sequence is bounded by well-defined sequence boundaries, observed in core and logs, with well-defined transgressive systems tract (TST) and a highstand systems tract (HST), separated by a mappable maximum flooding surface (MFS).
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The Khuff Multi-dimensional: Results From Outcrop Analogue Studies in Oman
More LessThe Permian–Triassic Khuff platform is a classical epeiric sequence with limited seismicscale reservoir geometries. It is referred to by some as the thickest “pile of grainstones on earth” and shows significant variations in productivity.
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Lithofacies Variation and its Consequence on the Reservoir Quality of Kangan Formation in Fars and Persian Gulf Area
More LessKangan Formation of Lower Triassic is one of the most important hydrocarbon reservoirs in Fars and Persian Gulf areas. The Kangan Formation unconformably is underlain by Permo-Triassic while its upper boundary with Aghar Shale Member of Dashtak Formation is conformable. Containing mainly carbonate rocks, Kangan Formation is interbedded especially in the Upper part with shale and claystone which can be considered as equivalents of Sudair Shale sourced from south west. In some parts of the Fars area, the nearly clean carbonates of the Kangan Formation ranging from tidal flat to shoal in terms of depositional environment, abruptly change to argillaceous limestone and shale of outer ramp (Figure1). In this case, a clay content map provides a powerful mean to delineate the area rich in clay; where is called "Gray zone"(GZ) hereafter. With a length of 350 km., a width of 100 km and an Azimuth of 150°, the GZ extends from Khalfani field located on the coast of Persian Gulf to Dashtak field in interior Fars area, forming ~30° angle against main Zagros fault.
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Earthquake-triggered Post-depositional Deformation at the Rim of the Arabian Platform (Permian–Triassic, Oman Mountains)
Authors O. Weidlich and M. Berneckerthe eastern rim of the Arabian Platform. It represents a lateral equivalent of the Khuff Formation, a major hydrocarbon reservoir in the Middle East. Late Permian to Early Triassic deposits comprise the following sequence of lithofacies associations in Wadi Aday located in Saih Hatat, in the eastern Oman Mountains (Weidlich and Bernecker, 2011, Figure 1).
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Pre-Permian Extensional Deformation and Uplift in the Central High Zagros, Iran
Throughout the Arabian Plate (Figure 1), a more-or-less prominent sedimentary hiatus separates the late Carboniferous (?)–Permian sequence from the older sedimentary formations. This hiatus and corresponding unconformity is generally named the “Hercynian unconformity” suggesting a relationship with the Hercynian (Variscan) Orogeny, which affected Western Europe and westernmost Africa during the Carboniferous. In the High Zagros Belt (HZB), which belongs to the Zagros Fold-and-Thrust belt (ZFTB), this pre- Permian unconformity exists everywhere. However, this unconformity seals truncated Lower Paleozoic strata and normal faults by the new mapping and field evidences (Figure 2).
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Using Gravity and Magnetic Data to Delineate Deep Basin Geometry and Faulting: Implications for Paleozoic Sourcing for Permian–Triassic Reservoirs in the Partitioned Zone/Divided Zone of Saudi Arabia and Kuwait
Within the Partitioned Zone/Divided Zone (PZ/DZ) of the Kingdom of Saudi Arabia and the State of Kuwait, Wafra Joint Operations (WJO) utilizes non-seismic geophysical technologies as a means of complementing and leveraging the value returned by seismic exploration efforts – this in order to optimize development of the PZ/DZ asset. Legacy gravity data available in the area (dating back to 1949) were confirmed and supplemented by a ground gravity program acquired in 2010. Future plans initiated by WJO include the execution of an airborne gravity gradiometry and magnetic survey using latest technologies.
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Depositional Sequences of the Lower Triassic Kangan Formation, Southwest Iran
Authors M. Ali Kavoosi, A.M. Jamali and M.R. Naiji and R. NematollahiThe Lower Triassic Kangan Formation is a major gas reservoir in southwest Iran. It is composed mainly of limestone and dolostone with evaporite interbeds. The lower and upper contacts with the Upper Permian Dalan Formation and the Lower–Middle Triassic Dashtak Formation are discontinuous but conformable. To study the facies and depositional environments of the Lower Triassic Kangan Formation, eight wells and the Surmeh outcrop section were studied. Field and petrographic studies combined with wire-line well logs analyses resulted in the recognition of facies related to tidal flat, lagoon, shelf margin, basinal facies tracts, which were deposited on a carbonate ramp.
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Reservoir Facies Controlling Factors in the Upper Permian Dalan Formation, Southwest Iran
Authors M. Ali Kavoosi, M.R. Naiji, A. Mahmoudi and M. Nazarian and A.M. JamaliThe Upper Permian Dalan Formation is an economically significant gas and condensate reservoir in the Fars region of southwest Iran. It is composed mainly of limestone and dolostone. Facies analyses, depositional environments and diagenetic processes of the Dalan Formation in eight wells and the reference section at the Surmeh Anticline were studied. Field and petrographic studies combined with wire-line well-logs analyses and available seismic images resulted in recognition of various carbonate facies related to tidal flat, lagoon, shoal, basinal facies tracts, siliciclastic and evaporitic facies deposited on a carbonate ramp.
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Microfacies, Diagenesis and Reservoir Quality of Early Triassic Kangan Formation in Offshore Zagros: A Case Study
Authors F.K. Harchegani and M.R. Kamali and B.E. DizajiSignificant amounts of hydrocarbon resources are hosted by the Lower Triassic Kangan Formation (Upper Khuff equivalent) in the southern part of Gulf. This carbonate gas reservoir is known to be a complex carbonate system with a high degree of heterogeneity, which has a direct impact on the reservoir quality. The formation consists mainly of limestone, dolomitic limestone, dolomite and evaporites. Combined core examinations and detailed thin section studies are used for facies analysis. Accordingly, 10 major facies were recognized in the Kangan reservoir. They are grouped as five facies assemblages deposited in supratidal, intertidal, lagoon, shoal and off-shoal environments. These facies associations reflect an ideal shallowing upward sequence. These facies are genetically related and indicate a gentle depositional gradient and morphology during deposition. Thus, they represent the shallow part of a homoclinal carbonate ramp (Figure 1). This interpretation is based on the characteristics of the constituent facies, lateral and vertical relations between sedimentary facies and the presence of thick succession of shallow-water deposits (high relative proportion of peritidal and lagoon versus open-marine facies).
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Prospectivity of Khuff Reservoir in Southwest Kuwait
Authors M. Rahaman and M. Ebrahim and S. Al-GhareebThe Permian–Triassic Khuff Formation is an extensive gas reservoir in the Arabian Gulf area. The formation houses the world’s largest gas accumulation: the combined North Field (Qatar) and South Pars (Iran) dome, contain approximately 1,500 TCF of gas (Halbouty, 2003). The formation was deposited during a regional transgression over a stable shelf of very low relief, which had minor clastic supply on the margin of Arabian Peninsula. The porosity and permeability of the Khuff carbonate reservoirs are generally very low in the entire Middle East. Ehrenberg (2007) showed that porosity in the Middle East varies from 2–14%, where the depth of reservoir varies from 2–5.5 km. To explore the Khuff reservoir prospectivity, post–stack seismic inversion and porosity modeling was carried out using recently acquired 3- D Q-Land seismic data. The study area consists of two major fields, Minagish and Umm Gudair, which are located over major structural highs. In the southwestern part of the Kuwait only one well was drilled to the Khuff-C reservoir over the structural high of West Umm Gudair Field. Here the Khuff-C reservoir occurs at greater depth and is around 350 feet thick. The observed porosity of the unit is around 2.0%. The testing of the unit could not be carried due to mechanical problem.
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Improving the Mapping of Permian–Triassic Layers using Inversion with Inter-bed Multiple Method: A Case Study of Mutriba Field, Kuwait
Authors Osman Al-Khaled, Y. Al-Zuabi and M. Rahaman and M. HafezThe onshore Mutriba Field, located in northwest Kuwait, shows some potential gas targets in the Lower Triassic to Permian formations. These levels are well known in the Middle East for being severely contaminated by coherent inter-bed multiple reflection events in the seismic data. These multiples have the same velocities as the primaries and cannot be adequately attenuated during processing. As a result, the acoustic impedance (AI) predicted from such seismic data is significantly affected. We present here an inversion study, which incorporates an Inter-Bed Multiple Modeling (IBMM), into the generation of synthetic seismograms, which are involved into the seismic inversion workflow.
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Integrated Formation Evaluation and Production Potential of Pre-Jurassic Formations in Kuwait
Authors A. Rabie, R. Husain and M. Al-Mukhaizeem and A.M. Al-FaresThe Permian–Triassic Khuff Formation is an important hydrocarbon exploratory target in view of its proven potential in countries adjoining Kuwait. The formation, divisible into A, B, C and D units, is comprised of dolomite and limestone (mudstone-wackestone with rare packstone and grainstone) with subordinate shale and anhydrite. The formation is interpreted to be deposited in sub-tidal to supra-tidal environment with development of shoal and lagoon under hyper-saline conditions in restricted setting. Diagenetic history is complex and sediments have undergone multiple diagenetic events that include micritization, dolomitization, anhydrite cementation, leaching, stylolitization, fracturing and fracture filling. In the north, the formation is over dolomitized and can be categorized as tight nonconventional reservoir. In the west the formation has shown development of grainstone in Khuff C with significant porosity preservation. Here, the formation has shown hydrocarbon potential on logs but the testing results did not match the conventional log interpretation. This has adversely impacted the hydrocarbon assessment of this formation. To analyze the inconsistency, petrophysical and testing data were re-evaluated.
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Post-stack Seismic Processing Refinement Facilitating Khuff and Pre-Khuff Exploration: Case Study from Shallow Marine Offshore Abu Dhabi
Authors M. Mahgoub and Saif Al-MesaabiThree 3-D ocean-bottom cable (OBC) seismic surveys acquired in offshore Abu Dhabi have been subjected to ADNOC’s in-house post-stack seismic refinement routine. The objectives were to resolve the tuning effects caused by various stratigraphic features and enhance fault imaging at the deep Khuff and pre-Khuff targets. There were some remaining persistent issues, such as: (1) noise; (2) strong short wavelength jitters of the acquisition footprint, which degraded the stack continuity even at depth; (3) multiples; and (4) the relatively lowfrequency bandwidth of the final data. These issues hampered the interpretation of the data after the imaging stage.
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Sequence Stratigraphy of the Permian–Triassic Upper Khuff Carbonates, Ghawar Field, Saudi Arabia
Authors R.K. Al-Dukhayyil and J.F. Read and A.A. Al-TawilOver 1,500 meters of Upper Permian Khuff B/C and Early Triassic Khuff A and B cores and wire-line logs from 16 wells in Ghawar Field were studied. The carbonate-evaporite successions are interpreted to be arid epeiric ramp facies, which include: subaqueous laminated-and supratidal nodular- to massive anhydrite, tidal flat laminites, lagoonal mudstone, (with thrombolites restricted to Triassic), ooid-peloid shoal complexes, and subtidal off-shoal mudstone. Facies are packaged into meter-scale parasequences, often separated by exposure surfaces at sequence boundaries.
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The Application of Phytolith Stratigraphy to ‘Barren’ Red-beds
Significant oil and gas reserves occur in so-called “barren red-beds” in several regions around the world. Although red-beds occur throughout the geological timescale, examples with an economic interest are the Late Carboniferous, Permian and Early Triassic of Europe (Barren Measures, Rotliegendes, Bunter; Doornenbal and Stevenson, 2010), the Triassic of the United States, and the Permian–Carboniferous of the Middle East. These sediments are generally deposited in nonmarine environments under arid climate conditions. In terrestrial basins, biostratigraphic analysis of plant microfossils (pollen and spores) is often effective in constraining static geological models. Unfortunately, such organic-walled microfossils are not preserved in red-bed deposits due to oxidation, hampering stratigraphic correlation on both local (field) and regional scale.
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Heterogeneous Gravity Data Combination for Geophysical Exploration Research: Applications for Basin and Petroleum System Analysis in the Arabian Peninsula
Authors R.A. Fattah, S. Meekes, Y. Schavemaker, E. Guasti, J. Bouman and M. Schmidt and J. EbbingThe GOCE satellite gravity mission was launched in 2009 to measure the gravity gradient with high accuracy and spatial resolution. GOCE gravity data may improve the understanding and modeling of the Earth’s interior and its dynamic processes, contributing to new insights into the geodynamics associated with the lithosphere, mantle composition and rheology, uplift and subduction processes. However, to achieve this challenging target, GOCE should be used in combination with additional data sources, such as in-situ gravimetric, magnetic, and seismic data sets.
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Breccia Beds in the Khuff (Permian–Triassic) in Ras Al Khaimah, United Arab Emirates: Collapse or Transgressive in Origin?
Authors S. Fontana, S. Morad, F.H. Nader and A. Ceriani and I.S. Al-AasmThe laterally extensive, so-called mid-Bih breccia beds occur in carbonate successions of the Upper Permian–Lower Triassic Khuff-equivalent Bih Formation in Ras Al Khaimah, United Arab Emirates (UAE). These carbonates have been deposited on a stable platform setting at the passive margin of the Neo-Tethys Ocean. The breccia beds have previously been interpreted to be formed by dissolution of sulphate beds by groundwater followed by collapse of overlying carbonate beds (Strohmenger et al., 2002; Fontana et al., 2010). Contrary to this earlier interpretation, we present several lines of field, petrographic, isotopic and fluid inclusion evidence suggesting that the “breccias” are intraformational conglomerates representing a major marine transgressive surface.
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Delineation of Khuff Reservoir in Kra Al Maru Area of Kuwait Using Seismic Inversion and Lithology Modeling: A Case Study
Authors H. Shereef, O. Al-Khaled and Y. Al-Zuabi and T. Al-RashidA seismic reservoir characterization study was carried out over the Kra Al Maru structural trend in Kuwait to model the lithology of the Permian–Triassic Khuff reservoir. The dominant lithologies of the Khuff Formation are dolomites and dolomitic limestone with thin inter-beds of anhydrite and shale. The Khuff Formation has been divided into three units based on the lithological characters observed from one well. All three units contain dolomites, limestone, anhydrite and shale. The seismic data used was processed in 2005 with 25 meter bin spacing. Only one well was available for this study with the required log suite. The technique used was the Constraint Sparse Spike Inversion (CSSI) to produce the Acoustic Impedance (AI) volume. The principle objective of seismic inversion is to transform seismic reflection data into a quantitative Khuff rock property. A relationship between the acoustic impedance (AI) log and porosity log was established using the available well data to transform the AI volume to lithology volume.
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Faults and Fractures in Carbonate Reservoirs: Khuff Formation of Arabian Peninsula
By A. MoustafaSeveral factors control the distribution of faults and fractures in reservoir rocks. These include the regional stress field, local strain due to the existence of larger structures, deformation history, presentday stress field, diagenetic changes, and mechanical stratigraphy. The regional stress field that affected the eastern part of the Arabian Plate since Permo-Triassic time involved extensional tectonics (leading to development of normal faults) during Permo-Triassic breakup of Gondwana and opening of NeoTethys as well as compressional tectonics (leading to folding, thrusting, and positive structural inversion) at later times (Coniacian to Recent). This stress history led to the development of fold traps (N-S asymmetric folds in east Arabia and NW-SE folds to the north and east). The local strain associated with the fold/fault structures led to the development of small-throw faults dissecting the fold traps as well as several sets of fractures in the Khuff and other reservoirs. Some of these fractures are related to the regional stress field and others are associated with the folds and/or fault-damage zones. Reactivation of the Permo-Triassic normal faults during later phases of compressional tectonics and development of N-S fault-propagation folds was probably associated with trishear deformation in the steep anticlinal flanks leading to additional fracturing of the rocks.
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